ascott 500 head swap onto a 350x.... with pics [Archive]

SWIGIN

01-05-2008, 05:02 PM

ok i finally i got my hands on a ft 500 head (ascott street bike) i got the stock 350x valve cover to fit with alot of tig welding and mill work. (you need to use the 350x valve cover since the only way for the oil to get to the head is the external oil line witch the 500 cover dont have)

the only problem im going to have is the 350x rocker arms are only about 1/2 on the valve stems. 1 out of the 4 ajusters is close to being dead on but the other 3 are off about 1/2 way.

i did a search but it brought up nothing usefull. what i need to know is if xr500 or ft500 (ascott) rockers will fit into the 350x valve cover and do the 350x rocker shafts have the same diameter as the 350x.

if anyone has a xr500 or ft500 i would love to see pics of the rockers and shafts and maybe get some measurements from you.

thanks

SWIGIN

01-05-2008, 08:59 PM

i just checked my 350x rocker shaft and it is .471 which should be 12mm.

does anyone know if a late 70s - 82 xr500 or ascot ft500 has that size rocker shaft?

4cylinders

01-05-2008, 11:49 PM

hey, why not use the 500 valve cover, and just drill it?

SWIGIN

01-06-2008, 01:41 AM

well for one, there is no just drilling it.....the speedo stuff is there on the ft500 cover. (which i dont have anyway)

the ft dont get oil to the top end from a external line... it pumps it up one of the motor studs..... kinda hard to drill a oil passage if there is nothing there to drill.

plus i need the 350x head mount and its just the easyest way to go.

your idea was a thought till i found out its not worth the bother... if it can be done at all

Jason Hall

01-06-2008, 11:14 AM

Here Is a picture of a 82 XR500 rocker cover. I also have the stock cam for this engine.

SWIGIN

01-06-2008, 11:26 AM

perfect!!! thanks

yeah if the xr 500 had a external oil line that cover would be the way to go.

just looking at the rockers they look like what i need..... do you know the diameter of the rocker shafts?

the 350x rocker shafts are .471 or i beleive thats 12mm.... if you could please measure those it would help a ton.

honda wants over $100 for each rocker for the 500..... id like to know this inside diameter (or shaft size) before i lay the cash down.
thanks

Jason Hall

01-06-2008, 11:34 AM

I will measure the shaft for ya. It might be an hour or so.

SWIGIN

01-06-2008, 12:20 PM

iv heard about this head swap way back in the late 80s or real early 90s when dirt wheels did it or talked about it. iv also always heard rumors about this swap but never talked to anyone who ever did it.

from what iv read every one says you throw the ft500 head on and bolt a 350x valve cover to it........ its not that easy.

first the head does not go right on but all it needs is the 4 motor stud holes drilled to 10mm..... then it goes right on

plus the ft and the xr500 head gets oil pumped up the one motor stud and the oil fills the little cam lobe area to be splashed around i guess. well a 350x gets oil from a external oil line that feeds right on the cam journals..... so you can see in this pic that i had to fill the ft500 oil feed hole with jb weld so the oil dosn't run right back into the case.

plus you can see one of the motor stud holes i had to drill to 10mm

SWIGIN

01-06-2008, 12:26 PM

so far the biggest thing was getting the 350x valve cover to ''bolt right on'' its not so easy....the black line shows where the ft500 head/valve cover ares was stock.

i had HREATV weld the top fin and we milled it off then shaped it some.

we also taped the new holes to 6mm for the valve cover bolts but the aluminum is thinner then i like but if they strip out you could get a nut under the fin and just tighten it that way

i also have a pic of the stock 35mm ft500 intake valve next to the stock 350x valve

in the second pic you can see how the 350x uses 2 large bolts just behind and between the valve springs and the ft head dont.

the ft has 2 studs sticking out of the bottom of the head ( no room up top for the 2 bolts) more on this later

SWIGIN

01-06-2008, 12:37 PM

last night i got a junk 350x cly to play with.... heres what the ft head looks like on a 350x cly.

every bolt lines right up except for the 2 bolts that (on a 350x) go down right between the valve springs.

the ft uses 2 studs that go out of the head gasket surface down into the cly and then a nut is used to tighten them. so i have to machine the cly to accept these nuts.

the studs dont line up with the 350x bolt holes but they are close and can be machined to work.

now looking down the sleeve you can see the valves are going to hit the cly since the 350x is 81mm and the 500 is 89mm...... but this is perfect for a 89mm big bore and you get to use a basicly un modified ft500 head gasket (the xr500 has a different case stud pattern and thats why the xr500 gaskets or even the head are not used)

the last 2 pics are the timming chain area, you can that from the top looking down the ft head is almost a perfect match to the 350x cly. but looking up from the bottom of the cly its not as close but i dont hink i will run into a problem....... but if it look like a problem it will be no big deal to match them up perfect

Jason Hall

01-06-2008, 07:55 PM

Yes the XR500 has the same size rocker shafts .471. Looks like a pretty complicated swap. Good luck with It, and let us know how she runs.

SWIGIN

01-06-2008, 10:48 PM

perfect... thanks jason

yeah theres more to it then all the rumors led me to beleive but i was looking at some ft500 forums and they say 50hp is no problem with this head.

now thats also a 500cc motor but with a 6mm stroker and a 89mm big bore ill be at 460cc.

could be fun!!!

thanks again

SWIGIN

01-08-2008, 08:01 PM

today i went to HRE and we moved one of the head studs that the ascot ft500 uses so it would line up with the 350x cly.

the hole with the arrow is the one we moved, it was real close ( like 2mm) so we moved it and threaded it for a 10mm stud (like a 350x) instead of the 8mm stud the ascot uses.

the odd looking stud showed on the other side of the head will be harder to deal with since it dont line up at all with the 350x gasket. it has a 12mm base and a 8mm shaft.

im thinking i'll just rethread it to 14mm and then thread my insert to 8 or 10mm since the new studs im useing are 95mm long.

this stud hole is just inside of the 350x hole in the cly so i will just have to make a new hole.

the last 2 pics you can see where im going to mill the cly so i can use nuts on these 2 long studs...... the factory ascot studs are short and only go to the first fin and i wanted more meat.

im going to mill out where the tape is and thats where the nut goes.

SWIGIN

01-08-2008, 10:25 PM

2 more pics tonight

i threw it together to see how long the top end studs would be...... the inner 2 look fine but the outer 2 will need spacers made.

with a brass washer at each end of the spacer it should work fine.

hmmmmm.......i wonder if the ft studs would work

SWIGIN

01-09-2008, 05:00 PM

145 views and no one has any questions or opinions?

i was hopeing for some insight from you guys but i guess this swap is to old school.

i read a artical in dirtwheels years ago.... maybe the late 80s about this swap and was kinda hopeing someone would throw it on here.

maybe this is the kind of thing only top motor builders at the time did ( TC, micky dunlop)

any way if you have some info id like to hear it.... it would be nice to see how other guys did this.

camatv1

01-14-2008, 02:54 PM

try contacting the people that did the original swap? maybe dirtwheels has an issue or can tell you the issue that had this swap in it? your best bet is to just figure it out on your own.. OR talk to someone thats done it before.. is it just the head thats going on? why not the entire cylinder and make it a 500cc? OR an xr600 engine?

SWIGIN

01-14-2008, 03:15 PM

im realy about done with the swap....just a few studs and things like that im waiting for.

yes its just a head swap....from what iv read online you CAN use the 500 cly as well but the time it takes to machine it to fit ( its way to tall) makes it not worth it.

what im doing is putting a xr500 sleeve into my busted 350x cly. this makes it a 89mm bore (same as a xr500)witch is exactly what the head is made for and the early xr500/ft500 head gasket lines right up.

plus useing the 89mm sleeve lets me use the early xr500 pistons and all the over bores they make.

this 89mm topend combined with a 6mm powroll stroker crank will be 460cc ( witch should realy run great since the head is made for a large motor)

im not going with a whole motor swap since my aftermarket 250r frame is built for a 350x motor ....and whats the fun in just throwing a big motor in....lol

i was just wondering if anyone here had info on how this was done back i the day, but im thinking other then a few top motor guys building a few each this never realy was a do it yourself thing

SWIGIN

01-15-2008, 05:46 PM

got some more parts to play with, thanks to jason hall for the rockers and cam

i had a problem with the 350x rockers only sitting about 1/2 way on the valve stems and in the first 2 pics you can see how much wider the xr500 rockers are and that they line up perfect with the ft500 valves. (in the first pic the xr500 rockers are on the left)

they go right in without any mods but the xr500 uses a little wave washer beside the rocker......for this swap they dont fit and are not needed. you just simply put them right in like a normal 350x rocker.

3rd pic shows the early xr500 (same as ft500) head gasket and the magic marker shows the last hole i need to make for this to be 100% bolt on.

the new hole is just inside the original hole and will work fine.... i like how all the head bolts or studs are close to the fire ring of the gasket (unlike a 350x )

4th pic shows the new 79-82 xr500 sleeve im going to be useing and as you can see the gasket is a perfect match since it is made for this sleeve.

the last pic shows the length of the sleeve is roughly a 1/2 inch to tall....this is one reason why useing the whole xr500 cyl is not a easy thing to do since it needs to be shortened and the timming chain area near the base gasket is way off and dont line up at all.

my buddy built a 89mm stroked 350x(460cc) like this one will be and all he did was put the new sleeve in a lathe and cut it down to the right lenghth....no big deal.

the last thing id like to say today is with a lot of big bores you need to ether buy a custom head gasket or mod and stock gasket to work. with this 89mm bore you would be cutting the main fire rind seal off of a 350x gasket and that can led to a head gasket leak.

but drilling the new hole in the cyl is all i need to do is run a off the shelf xr/ft500 head gasket with only opening a few holes up in the gasket.

now that i look at the 500 gasket on the stock bore 350x cyl the new piston isnt realy that much bigger

Dirtcrasher

01-15-2008, 07:25 PM

I think it's pretty awesome, lots of things to figure out there. I am unfortunately still stuck without a Tig welder but this year will be the year I buy one, just so tired of not being able to do the aluminum welding.

I think it was Dale that has a TC 86 200X head (single plug though) and it had at least one huge valve. I'm not sure if he's done any talking with anyone on it though.

I can see bolting a head down and setting up the bridgeport to cut larger valve seats, but I have no idea how much of a press fit that valve seat needs to be? Thats the problem with most motors, no matter what you do to the ports, the valves are too small. But not for you anymore! Nice work Swigin.

BTW, what does SWIGIN mean? I always picture a big fat guy swigin down a bottle of whiskey, LOL!!!!!

SWIGIN

01-15-2008, 07:56 PM

lol
SWIGIN is from the HBO show deadwood

yeah i cant wait to see how a big cc 350x will run with this monster head....they run strong with the 350x head.

my brother had a dual sparkplug TC 200x (in a trx250r frame) and they really run strong but as far as the over size valves go they normally just go like 1mm larger and just open up the stock valve seat

SWIGIN

01-17-2008, 12:40 AM

tonight i went to HRE and i cut the new sleeve shorter.... after makeing sure i had room to spare i left the new sleeve 1/16 longer then stock sleeve since the piston will be going farther down in the bore.

then we bored the old cly for the new sleeve... last pic just shows the stock sleeve in the big bore jug

Louis Mielke

01-17-2008, 12:49 AM

looking good. I wanna hear the ride report

SWIGIN

01-19-2008, 01:55 PM

thanks man, yeah id like ride report too...lol

i found what i thought was a 92 or 93mm long stud from a 400ex cly ( #5 on the microfische)

well it came and its way over 100mm long...what the honda guy told me is the length must be the installed highth.

so i ordered a #7 400ex stud that called 73mm long, i hopeing like the other it will be 20mm longer making it 93mm like i want.

WLL

01-22-2008, 11:33 PM

more please!!! i like your motor work and thinkin:drool: . when can i buy the kit?:naughty: :drool: please add sound in the ride report, i gota here her run!!

SWIGIN

01-23-2008, 12:15 AM

i dont see me biulding another one of these even tho now i know what ill need .....the cost would be sky high.

i cant wait to run the thing too but that will be awile...never heard a big bore stroker with a monster head before...lol

Tecate performance

01-30-2008, 01:39 AM

RideRed250R

01-30-2008, 01:49 AM

what i like is its a hemi... lol

scrawny

01-30-2008, 02:00 AM

wow!!! cool stuff!

i cant believe the difference in valve size, are the exhausts that much bigger too? should be a screamer!!

SWIGIN

01-30-2008, 02:39 AM

looks awesome, want to do another one:D

i have a ft500 head that i was planning on retro fitting. i thought about plumbing an external line into the rocker cover. are the xr/ft and 350x cams the same? i think the timing gears are.

you may want to calll FST and ask him what he did, i know he used to build them. also greenhuman on here said he's done one. i've got the 452 kit on stock stroke, stock head and valves and its pretty strong. i'd like to try the ft head for a stroker motor though, especially when you get around 500cc. make sure to check your deck height when you're done, most of the aftermarket pistons use the same compression height as stock and it puts the compression in the basement. i had cometic make me some thinner head and base gaskets to correct the deck and get the squish right and it was pretty cheap.

fwiw, the 04-05 trx450r pistons will fit the 350x rod, the rod small end is a little wider though and the compression height is about .120" shorter. the valve relief dia. and angles however are in the wrong place.

i'll be running a mega cycle xr500 #144-20 or a #144-21 cam with a 10.5 xr500 piston with a custom header and a aluminum intake

what cam, intake, and exhaust are you running? be sure to keep us updated!

from what iv heard FST used xr500 heads and cyl....this is not as good as the ft head and its easyer to use the xr500 sleeve in the 350x jug then try to get the 500 jug to fit a 350x.

im not worried about the compression highth at all since powroll knows about using the xr500 pistons in the 350x and when they shorten the rod for a stroker they take that into concideration.

the great thing about this combo is all the parts are made to work with each other....like the ft head and the xr/ft500 piston has the right valve releifes...and yes a 350x cam and a xr/ft cam will inter change

if you run a xr valve cover you can get the oil to the cam but not directly on the journals like a 350x cover......the 350x has a better oiling system

look at the xr500 valve cover that jason hall posted at the start of this thread....and then look at my first pic, its a 350x cover......you will see how on a 350x the oil gets pumped right on the cam journals

SWIGIN

01-30-2008, 02:42 AM

wow!!! cool stuff!

i cant believe the difference in valve size, are the exhausts that much bigger too? should be a screamer!!

the ft500 exhaust valve is as big as the 350x intake valve.... 30mm

SWIGIN

01-30-2008, 12:52 PM

ok iv bin sick as a dog since sunday but i think im starting to get over it and i felt like takeing more pics to show how its comming.

first pic is the 400ex cly stud i ordered from honda i had to cut about 4 threads off it but its the only thing close i could find. in this pic you can also see the stock short stud the ft 500 uses.... i wanted longer ones to make it more ''meaty''....the stock stud only goes to the first air fin, i wanted more.

2nd and 3rd pic is showing how the 400ex stud will be when done....i still have to put the cly in the mill and clean up the area.

i just hacked at it with a cut off tool to see how the stud looked.

4th pic is the outer 2 top end studs that were to long....after doing some homework i found that 250x,250sx, 250es, 300ex all use slightly shorter studs.

luckily my brother had some and i threw them in......one works perfect and the other sill needs a little spacer made but its better then is was.

5th pic shows the 350x stud length

last pic is the 250x studs and the top end together

SWIGIN

02-03-2008, 11:32 AM

ok...i think im done with machining parts finally...lol

first pic shows the spacer i had to make for the shorter 250x stud

2nd shows the threaded insert we made so i could use a 8mm stud in the head like the head had stock (stock stud had a 12mm base and i needed...or wanted a longer stud)

3rd pic shows the longer 8mm stud

SWIGIN

02-03-2008, 11:39 AM

here is the cly.... the ft500 and the xr500 uses notchs like this so you can get to the studs to put the nuts on

the rear stud on the ft500 head is the one that almost lines up with the threaded hole in the cly so we moved it 1 or 2 mm to line it up.

the front stud on the head (the one with the threaded insert) needed a new hole in the cly just inside the original 10mm hole and i used the stock ft500 size 8mm stud but i got one longer. i didnt want to use a 10mm stud here since the 2 holes are real close together and the head gasket is made to work with the 8mm stud.

well that will be about it for a awile..... i have to other things that need worked on but this shows what all is needed to make this swap work.

not as easy as all the rumors say but now we all have something to go on for the next one

Yamada

02-03-2008, 12:08 PM

I think you should work for the NASA men!!! Nothing stop you. When done, I wish you are gonna write a ride report...

oldskool83

02-03-2008, 07:27 PM

I think you should work for the NASA men!!! Nothing stop you. When done, I wish you are gonna write a ride report...

oh i am sure he will do a ride report...this current 350 i thought was crazy...this new one should be crazy insane haha.:lol:

evand

02-04-2008, 08:31 PM

man thats a sweet set up! should make some nasty power, be up there with the new 450.

when are you expecting to have it in?

we def. need a ride report. with sound!!! what exhaust are you runing?

brapp

02-04-2008, 11:12 PM

scrawny

02-05-2008, 12:13 AM

looking good~!

that intake port is HUGE! lol a dyno run would be cool. :D

350xrider911

02-05-2008, 01:26 AM

what the differnce between the bottom end. on the ascott and the x. why not just mod the hold motor to fit, will the bottom end hold up to the 500. with it being a 20 years old.

SWIGIN

02-05-2008, 02:34 AM

man thats a sweet set up! should make some nasty power, be up there with the new 450.

when are you expecting to have it in?

we def. need a ride report. with sound!!! what exhaust are you runing?

thats the idea...then some

no time line... i need to get my mustang on the road for spring

ill make a custom header from scratch and use my 2'' pipe im running now

SWIGIN

02-05-2008, 02:37 AM

hey man awesoem work! i have tought abotu dign this for a while also but decided to just use the 450r motor. wellhave to se ehwo they run and you should come up soemweekend with your brother we had a blast the last weekend.

all my buddys have 450s so thats the kinda the reason for this... all thoe on a tight mx track the 350 dont do bad

i always say im going then i chicken out...lol since my knee surgery years ago the cold realy bothers them so let me know when it warms up and is dry and ill try to make it up...thanks

SWIGIN

02-05-2008, 02:38 AM

looking good~!

that intake port is HUGE! lol a dyno run would be cool. :D

i do know a guy with a new atv dyno....hmmmmm

SWIGIN

02-05-2008, 02:39 AM

what the differnce between the bottom end. on the ascott and the x. why not just mod the hold motor to fit, will the bottom end hold up to the 500. with it being a 20 years old.

i answered this back a page or 2 but short answer......why not

NOS_350X

02-05-2008, 03:44 AM

Awesome project. Glad the way its comming along. Cant wait to see it run. I have a few ideas on some new things im goint to try on the new X i got in the near future (hopefuly in a year)

SWIGIN

02-05-2008, 01:19 PM

sounds good man...i'll be waiting for and expecting a full wright up...lol

scrawny

02-05-2008, 01:28 PM

i do know a guy with a new atv dyno....hmmmmm

let me be the first to guess...

im going to say 44 hp. ever figure out what compression its going to end up being?

SWIGIN

02-05-2008, 01:39 PM

yeah im useing a 10.25 or 10.5 ( whatever they call it)

since the piston is made to be used with this head im thinking the addvertized compression ratio should be right

im keeping the comp low and the cam on the small side to lenghthin the fuse on this time bomb...lol

you might be real close on the hp guess ...... we will see

Dirtcrasher

02-06-2008, 09:13 PM

All nice stuff SWIGIN!!

Funny though, this just proves what BS is out there. How many of us have read that the "ascott swap" just needed a few minor mods to get it to fit. LOL... Turns out it takes big mods, allot of machining and plenty of brains. At least you have posted it for us all to know what is truly involved in this swap.... Thank you.

NOS_350X

02-07-2008, 01:53 AM

Quick question, for you Swigin, Is a ascott 500 cam a drop in for a 350x?

SWIGIN

02-07-2008, 03:56 AM

Quick question, for you Swigin, Is a ascott 500 cam a drop in for a 350x?

i would think so....i have a xr500 cam witch should be the same as a ft500 and it fits perfect in the 350x head

edit..... on second thought i know its a direct fit

SWIGIN

02-07-2008, 03:57 AM

scrawny

02-07-2008, 11:13 AM

about the cam swap:

do the pistons deck out the same between the 500 and 350x? you might run into piston/valve clearance problems. just a thought...

SWIGIN

02-07-2008, 02:49 PM

the 500 piston pin is like 3mm lower then the 350x so the piston is higher but powroll knows this and shrinks the rod the extra amount.

if you had a old streched timing chain you could also run a 3mm cyl spacer

in other words my 500 piston will be as the 350x highth and lower then the 500 highth so valve clearence will be nothing to worry about

scrawny

02-07-2008, 04:30 PM

no i meant running just the 500 cam in a 350x, like NOS said.

SWIGIN

02-07-2008, 05:03 PM

it will work since the xr500 cam is not much different then a stock 350x cam spec wise

stock 350x specs... .313 .303 lift 221 221 dur

i dont have stock xr500 cam specs but here is mega cycles smallest drop in cam

.333 lift 234 242 dur

i would think a stock 500 cam is not even that big

now heres the 350x race cam iv used in the past

.405 lift 249 dur.... with any cam you need to check for clearences

but whats so nice about this head swap is i can use all the xr500 cams without any special clearnceing other then the normal need to maybe shorten the guides and check piston clearence

if you want to see the 2 cams im thinking about its megacycle #144-20 and #144-21 but im leaning toward the smaller #144-20

scrawny

02-07-2008, 11:46 PM

good info to know!!

ya got me lol! ive only got the biggest web cam which is as follows: .392 lift and 279 duration. runs good likes to rev. ;) especially with the relatively small 82mm wiseco and a stock stroke.

The Goat

03-13-2008, 11:26 PM

SWIGIN

03-14-2008, 06:06 PM

is any other topend just a bolt up? machining the cases if the sleeve doesn't fit, but besides that.

I'm doing a highlift cam, but i'm curious about air flow, seems like it would benefit from a lot more.

sorry man, im not following you

this dont just bolt up if thats what you mean, and you dont think this head will not give enough air flow?

The Goat

03-14-2008, 09:07 PM

lol...if you calculate when that post was written you'll see it was at a very random hour. I've been up since....jeez...uh 2 p.m. thursday. exams this week.

your headswap is perfect, but, it's also a bit more labor intensive, and expensive than i was looking for.

Dirtcrasher

03-16-2008, 08:11 PM

I think GOAT was asking if any other larger topend was close to a bolt on a 350X with maybe some case work but not all the intense work - drilling/welding/fabricating that goes into this ascott head swap.

SWIGIN

04-05-2008, 09:07 PM

i have a 460cc 350x update but not my motor.

my friend got his big bore stroker running today, now his is built the same as mine right down to the cam and carb except he's running a 350x head and not the ascott head and let me tell you THAT MOTOR IS FUN

i realy cant wait to get mine running now! his is so smooth and strong yet so rideable its sick.

it feels like a worked up 450 but it has tons and tons of torque.......as soon as my track dries out i'll let you know how it does against the 450s

Dirtcrasher

04-05-2008, 09:26 PM

Not a doubt in my mind..... It's gonna be completely NASTY!! :crazy:

We'll all want some video :D

That was quite a bit of work and number crunching to get that Scott bolted on. You won't see many guys do that... :beer

atczack

04-08-2008, 06:43 PM

Can't wait to see the ride report or some video! It just so happen's I am swapping out my worn 350x cylinder for a new one this weekend, maybe I'll ship my old one to you and you can fix me up like your's! lol Good luck man.

SWIGIN

05-05-2008, 06:07 PM

well i got a ride report......the 350x clutch wont hold with this much power

my buddy is on his 3rd clutch (in a month).......stock fibers with barnett springs, barnett clutch with new barnett springs, he even tried a ebc or vesrha kit.

the barnett fibers with new factory steels and new barnett springs held up the longest.....like a hour tops.

im screwed with my 460cc with a ascot head untill we can get his clutch to hold i have no hope for mine (im bigger then him and my bike is heavier)

we are trying to find what it will take to get a ascot ft500 clutch (witch has a extra steel and fiber disc) in a 350x motor but if anyone has one or even a early xr500 clutch complete id be interested in it to fool around with and see if we can get these monster motors to hook.

now with that all said it still (with a sliping clutch) eats all my buddys race preped and modded 450 quads....lol

Louis Mielke

05-05-2008, 08:18 PM

NICE! Post some complete pics with the engine in the frame all buttoned up ready to ride.

SWIGIN

05-05-2008, 08:25 PM

its not my motor thats done...its my buddys 250x/350x quad....i posted pics of it before...it looks no different since he runs a 350x head.

SWIGIN

05-05-2008, 09:07 PM

since i typed my last post my buddy called me and said he just got done doing some machine work to a 350x basket and inner hub and he got it to take a extra steel and fiber disc....just like the ascot 500/ xr500 motors have.

so we will see if this holds up

Tecate performance

05-07-2008, 03:46 PM

good info on the ascott clutch, and pics please when its done:)

you may want to try clutch springs from FST, the 'green' ones. i've used them in my 450 350x and 380 300ex motors and they hold great, although those have stock stroke cranks. i always have best luck with oem plates.

also, what cam did you guys end up using?

SWIGIN

05-07-2008, 05:23 PM

if his holds up then ill machine a old clutch for mine and get pics

as far as cam hes using a megacycle xr500 #144-20

im ether going with that cam or the next one up #144-21

but ill probaly go with the smaller one since i dont want this thing to make tons of power way up high. his runs real strong down low thru the mid range with the 144-20

SWIGIN

05-07-2008, 08:28 PM

i just got off the phone with my buddy and he said it didnt hold ether so we are both dead in the water.

i know back in the day guys like TC and sparks had 475.. and bigger 350x motors but i cant beleive this combo over powers the clutch like it does.

back to the drawing board

Billy Golightly

05-07-2008, 09:11 PM

Ya need to mod a lockup style pressure plate from a 450 or 250r or something.

200x Basket

05-08-2008, 12:48 AM

i came across this tonight. he may have some info for you

http://forums.atvconnection.com/messageview.cfm/catid/8/threadid/264172.cfm

SWIGIN

05-08-2008, 06:58 AM

Ya need to mod a lockup style pressure plate from a 450 or 250r or something.

iv heard people talk about a lockup clutch....what is it?

and i thought a 250r had a old normal clutch......if the R has or can use a lockup deal then i should be able to as well since the disc's are the same diameter.

any info on this setup would be GREATLY needed and apreciated

SWIGIN

05-08-2008, 07:25 AM

ok...i searched lockup clutch and i seen what they look like ....kinda the same idea as a centerforce clutch for a car.

but the problem is the 250r and the 450r are push rod clutchs witch works totaly different then a 350x....any ideas?

and if you look at a xr500 ft500 or a 450r clutch on bike bandit they all run a judder spring....what is that?

the 350x dont run this spring.... i think im going to try to get my hands on a ft500 clutch since those roundy round guys can get 80hp out of a ascot motor (from what iv seen on thumper talk) and i guess they dont have clutch problems.

Billy Golightly

05-08-2008, 08:41 AM

http://gigotracing.com/index.php?option=com_content&task=view&id=13&Itemid=1

Have a look at these too, or give him a call. They are not the "normal" lockup style and are a lot more contained/smaller. It works off of metal balls, like out of ball bearings. They sit in the middle and when you dump the clutch they all sling out to the outside of it and apply the more pressure to the clutch plates.

SWIGIN

05-08-2008, 05:15 PM

my buddy called up micky dunlope and he said for his old 505cc motors they needed to use custom clutch springs to get them to hold.

he also told him that normal hd springs are junk and and are made for stockish motors.

so now we are going to measure the highth and diameter of some barnett springs and see if barnett can give us the poundage of these springs and see if they have a spring the same size with more presure.

if not we are going to check into valve springs....acording to micky with the ''right'' springs and a easy pull lever it should be hard to pull the lever in...as in real hard like a grooved basket.

he said he used to get custom springs made just for 350x monster motors but that was years ago and the source dried up....wish i had a spring scale to measure spring strength but now there is hope

lndy650

05-08-2008, 05:54 PM

try calling Tom Carlson i talked to him before and he seems to be a helpful guy.

The Goat

05-08-2008, 05:56 PM

what about a spring shop in your area. I know there's a place around here that makes custom springs, no idea on the price though.

i got some defective ones back in highschool to build a catapult.

lndy650

05-08-2008, 05:56 PM

814-723-3514

Billy Golightly

05-08-2008, 06:19 PM

You can measure the tension of springs by compressing them on a regular old bathroom scale and see how much weight it takes to compress them a 1/2 or an inch at a time to find the spring rate.

SWIGIN

05-08-2008, 06:25 PM

try calling Tom Carlson i talked to him before and he seems to be a helpful guy.

iv bin to his house....he keeps things like i need to know to himself

he used to offer a clutch mod for this type of problem.....im starting to think it was just real heavy springs and maybe the extra disc

SWIGIN

05-08-2008, 06:26 PM

You can measure the tension of springs by compressing them on a regular old bathroom scale and see how much weight it takes to compress them a 1/2 or an inch at a time to find the spring rate.

i had the same idea......put the scale and springs in the press and go a certian amount to see witch is stronger

you were on the right track with the lockup deal.....but i think id need a new clutch cover to get that to fit

SWIGIN

05-08-2008, 06:28 PM

what about a spring shop in your area. I know there's a place around here that makes custom springs, no idea on the price though.

i got some defective ones back in highschool to build a catapult.

we have spring places too but small heavy springs are kinda hard to get made.....only a few places make small atv size springs that are heavy enough

SWIGIN

05-08-2008, 07:59 PM

ok at 1/2 inch compression stock 350x clutch springs are 53 pounds

stock 350x valve springs are high 40's and ascott valve springs are 50

i'll update this as we get to try more springs

Billy Golightly

05-08-2008, 09:01 PM

I'd look into some that came off streetbikes or something. I think I've read FZR600 springs interchange with banshee or something, so its likely others do as well.

The Goat

05-08-2008, 11:53 PM

SWIGIN

05-09-2008, 03:26 AM

my new R&D valve springs are RIDICULOUSLY heavy. I'd say well over 60 pounds, i honestly couldn't push them in with my thumb, and where I can easily squeeze one of the stockers in my palm...the R&Ds took a bit of straining.

just a heads up.

lol....thats not ridiculous enough

old worn out barnett springs ended up being 72 pounds and new vesrahs checked in at 75....the same as new barnetts

so the 4 new barnett springs that arnt holding is putting 300 pounds of presure on the clutch pack.

we did find some valve springs that will fit and they have 120 pounds each....once we get them and try them i'll post how they work.... but i think we are on to something

lndy650

05-09-2008, 09:36 AM

i wonder how its going to be pulling 480 pounds with a clutch handle

lndy650

05-09-2008, 09:39 AM

iv bin to his house....he keeps things like i need to know to himself

he used to offer a clutch mod for this type of problem.....im starting to think it was just real heavy springs and maybe the extra disc

now that i think of it that dosent suprize me i have a TC 350x head ported and oversized valves for a 450 big bore and he refused to tell me where to get the oversize valves. i think they were 32mm in. and 30mm ex.

SWIGIN

05-09-2008, 09:55 AM

i wonder how its going to be pulling 480 pounds with a clutch handle

not to bad..... i would say my clutch pull is on the soft side with barnett springs.

and at 75 pounds each thats 300 pounds so this is only 180 over that...there is always easy pull levers and easy clutch things plus you can always ad lenght to the clutch arm for more leverage.

the pull is the least of my worries as long as we can get it to stop slipping. ever ride a bike with a grooved basket? once your on the track you dont even notice things like clutch pull....till the end of the day....lol

The Goat

05-09-2008, 01:19 PM

I was estimating on those R&D springs. lol. guess I didn't know my own strength. So the Vesrah springs are the same as the Barnett, that's quite interesting.

Billy Golightly

05-09-2008, 03:09 PM

SWIGIN...heres something else to think of. If you find some springs that are to long, when you shorten them up will also stiffen them up at the same time.

SWIGIN

05-09-2008, 06:59 PM

true dat

but for now we are getting the strongest ones that don't need modified .......if they dont hold then we are going bigger

NOS_350X

05-13-2008, 03:07 AM

I would say its not the best idea to use a griding wheel to roughen them up. Take the on a garage, shop or sidewalk cement floor. lay them and rub them on it in a circular motion on both sides. This is a good way to get a temp fix on a worn out clutch. A grinder is going to leave it uneven i woud think.

SWIGIN

05-18-2008, 06:35 PM

update......the springs my buddy ordered were back ordered so he got the closest springs they had in stock that would fit. they are a little longer then normal clutch springs but they dont bind when compressed, and they are alittle stiffer.....150lb each.

so thats 600 pounds of presure and as of today his bike is not sliping and the clutch is not that hard to pull in.

the nice thing about these springs are that the outer spring alone is just over 100 pounds.... so even just the outers are a upgrade to normal HD springs....lol

the only mod needed is since the 4 posts that the springs go on are tapered the bottom coil or so of the inner spring needs to be chamfered some

SWIGIN

05-26-2008, 02:49 AM

the clutch has made it thru a day of rideing and i can tell you that his clutch pulls no harder then my buddys 450r with a vesrha clutch and springs

edit.... make that 2 days of rideing

SWIGIN

07-01-2008, 01:22 AM

this setup lasted a month but he reused glazed barnett fibers .....not to bad

now he's putting in factory fibers so we will see

Blown 331

08-16-2008, 09:20 AM

I have a copy of an article about this from dirt wheels I don't think it's real techical but its a good read. I tired to attach it but it says invalid file for some reason. If anyone thinks they can post it I will email it to them.
I have a restored 350X and four 79-82 XL500s. http://forums.stlmustangs.com/style_emoticons/default/popcorn.gif

SWIGIN

08-16-2008, 11:17 AM

nice!

that might be the article i read years ago....id like to see it again

hope you can get it posted

SWIGIN

08-16-2008, 11:18 AM

oh and as a update......the factory fibers are holding up fine

The Goat

01-02-2009, 06:41 AM

bump.

did yours ever see the dyno?

I know that the stock 500 only put out like 35hp...I'm just rather curious as to what yours put out.

also, what exact clutch springs did you end up using to modify the clutch?

SWIGIN

01-14-2009, 02:09 PM

sorry, didnt see this till now.

mine is still sitting ready to be filled with parts, but till work picks up im not doing anything to it soon.

my buddys 460cc motor hasnt seen a dyno yet but he keeps saying he wants to......he's my porter i told you about and he has his hands full right now with personal stuff.

his has a stock ported 350x head and not an ascot head.

he did the homework to find the a spring that fits and asked me not to tell.....but we will order anyone some if they want some.

greenhuman

02-05-2009, 02:49 AM

I did this head mod in 1994 and I used a Powroll stroker and a 92mm FT500 forged big bore kit and FT performance cam with a 38mm keihin PJ carb. I got Powroll to shrink the rod an extra 3mm so I didn't have to modify the piston.

SWIGIN

02-05-2009, 09:00 PM

greenhuman

02-06-2009, 12:30 AM

The FT500 head with the 350X rocker cover and resleeved the 350X cylinder. I didn't have the decompression cable adjusted properly and it back fired and broke a main bone in my foot. 5 weeks in plaster.

SWIGIN

02-06-2009, 12:47 AM

did you do it similar to how i did it?

i find it funny when guys call this head swap a ''bolt on''

lndy650

08-17-2009, 07:43 PM

heavy duty springs from Mickey Dunlap work great with a stock clutch. he said not to use aftermarket plates new honda plates are the only ones that will hold up...
these springs work great on my 452 and they were only $20
fourstroketech.net

lndy650

10-17-2009, 10:26 AM

SWIGIN do you have any videos of you or your buddys bigbore? im curious how they run with the stroker. mine is just 92mm bore and stock stroke because i prefer power up high. (and a 350x will always have gobbs of torque no matter what...)

SWIGIN

10-18-2009, 09:13 AM

no i don't but maybe my daughter can get a video with her phone.

we talked to mickey and he told us that he used to get custom clutch springs made but that source has dried up.

every HD clutch spring i tested checked out at 75 pounds at the installed height, the springs we need and use are rated well over 100 pounds.

leevarnado

11-24-2009, 11:17 PM

any updates on your buddy's clutch

SWIGIN

11-27-2009, 06:45 PM

still going strong

the valve springs are a must for this kind of build

Shorty

05-01-2010, 06:31 PM

Need update please.

jonathandexter

05-02-2010, 02:15 AM

OMG. Sorry for stating the obviouse, but why can't you just soup the beeejeeesuuuuss out of the 350x head and or motor, and be done with your upgrade, Switch to HOT fuel ??? !!! My good-ness this is nonsense and and quite frankly, More money than brains, than I have ever seen before!!! I really really am sorry!, for being so rude but this is just NUMB!!! Better yet. If you got the money Slam in a 500 R 2 stroke in there and hang the F--k on dude!!! How the F would you ever repair the thing later on if you blew something????????????????????????????????????????? ?????????????????????????????????????

Jonathan

SWIGIN

06-07-2010, 12:25 AM

if this head swap scares you, thats fine but I'm OK with it.

This swap was an old school deal that I have wanted to do for 20 years....so I did.

It is that simple.

bandito90

06-07-2010, 12:49 AM

I was rather impressed by the size of the ports and valves on the Ascot head.I also think you did a great job on the fabrication end.

Vealmonkey

06-07-2010, 12:54 AM

I just got to see this conversion in person and it's truly amazing. As nice as the finished product looks, it has alot of time and figuring in it. And to see the stock ascot 500 valves being bigger than the 350x valves is pretty wild. Let alone the 350 sleeve fitting into the 500 sleeve. It's huge.

krazykane

06-07-2010, 11:08 PM

so how does it run

SWIGIN

06-08-2010, 04:21 PM

My motor is on hold for who knows how long. No need to ask for an update, I will update as things happen.

TheRealFatShady

07-03-2010, 08:44 PM

I'm starting to get interested in this swap....maybe I am overlooking something, but is using a full ascot 500 engine a possibility? That way there wouldn't be the problem of an external oil line or anything like that to the head. Just motor mounts needed?

SWIGIN

07-03-2010, 10:52 PM

Fitting that into your frame might be a bigger deal then doing what I did. I'm putting this motor in my 350RX and it has a chromoly frame, I'm not cutting it up for a different motor. The 350x motor is smaller and lighter then a 500 motor too.

The main reason for this thread was to stop all the rumors that the ascot head was a easy bolt on.....it is not. And I have heard these rumors for 20 years or so and just wanted to see how it works.

The nice thing is now that the work is done and it all fits together, my motor uses all off the shelf parts. No custom pistons, no custom gaskets, just easy to find parts.

Dirtcrasher

07-04-2010, 12:36 AM

It's no joke, no simple task. If you read the whole thread you'll see all he had to do and things made up etc etc........

big specht

07-05-2010, 09:58 AM

SWIGIN

07-05-2010, 10:28 AM

Hey SWIGIN I just read throught the hold thread GOOD INFO but I have some qwestions what clutch springs did you use I read they are 150#ers and from where??? and do you know the differance between the 500 head and the ascot head I have a good 500 head. Have you guys had any problem with the tranny. and what size carb are you guys running. We have used a electron flat slide 40mm with good results on the pulling bikes but they are just pretty much held wide open when pulling. Just looking for Ideas cause I have a stroked 350 bottom end with a 500 sleeve already in a jug and a ported 350 head setting there just waiting to put together.

I have heard the XR500 has slightly smaller valves/porting but I never had one to look at so I don't know about that. Some xr500 heads i guess had that odd reed setup and will not flow as good as an Ascot head. I think a 40mm carb would be better then the 38PE my buddy uses but we ride MX and don't really need a super large carb. Our thinking was the smaller carb would run out of snot and limit the RPMs and make the motor live longer. In reality the motor pulls so hard down low and mid range you can short shift it right past any built up 450r or yz450....this type of motor is truly sick.

If factory fibers and HD springs wont hold together for you I can get you a set of the springs we use. I did not do the home work to find these springs and my buddy who did does not want me to say. He will order you a set and like I said they are valve springs so they are not cheap.($120ish) PM me if you would like a set.

big specht

07-27-2010, 08:23 AM

Did you guys ever get any hp readings on these motors. I went pulling last week and I need MORE POWER . I need to know if the head is worth the extra work. THANKS

SWIGIN

07-27-2010, 05:23 PM

No, but we always talked about it. It really don't matter to me that much.

big specht

07-28-2010, 08:20 AM

Do you guys notice any differance in power between the bikes

SWIGIN

07-28-2010, 06:01 PM

Well, like I said I don't know how many times in this thread, My ascot headed motor is NOT running. I was talking about my buddys 350x headed 460cc motor.

That motor runs away and hids fron built up 450s.

atcmanic350x

08-08-2010, 12:32 PM

is the trike done now ?

Dirtcrasher

08-08-2010, 01:25 PM

He's building it for his one off chrome moly quad, not a 350X.

SWIGIN

09-19-2010, 07:58 PM

Since I will most likely never really ride again (knees and shoulder) I have been in no hurry to throw money at my 460cc 350x project. But I have sold the top end to a member on here and I will let him come forward if he wants to be known. He IS going to have me assemble this top end on his bottom end once I go through it. Everything will be the same as if it were going in my quad....but as of now it is going in a custom trike frame. I will be posting pics again as things progress so there will be a end to this thread sooner then later!

Vealmonkey

09-25-2010, 09:02 AM

Wow, what a lucky SOB!

Shorty

09-25-2010, 04:42 PM

If I knew you were selling that motor I would have bought it in a INSTANT!! NO questions asked.

Vealmonkey

09-25-2010, 07:09 PM

It's not a complete engine, just a collection of some really neat bits. Sound like it's getting put together as a complete engine though. I've been lucky enough to see the bits in person before. Cool is not the word.

SWIGIN

09-25-2010, 08:36 PM

If I knew you were selling that motor I would have bought it in a INSTANT!! NO questions asked.

Send the cash and I'll build you one too.............

SWIGIN

09-25-2010, 08:37 PM

Wow, what a lucky SOB!

Yeah, the poor guy has NO idea what he got himself into!

LOL

oldskool83

09-28-2010, 09:26 AM

are you gonna be selling the 350RX chassis? id love to have that as a roller.

SWIGIN

09-28-2010, 05:00 PM

Um........no

I doubt that will ever be for sale.

redneckjetski

07-19-2011, 09:58 AM

What ever happened to the motor did it ever get built?

the great gazoo

07-20-2011, 06:29 PM

I think another member here has it.
Oh, I gotta question, was/is there a donor Ascot roller, Swigin? I'm looking for an FT500.

SWIGIN

07-20-2011, 09:11 PM

No, no roller, I just bought the head off ebay.

A member on this site bought the Ascot parts from me but I am going to put it together for him when he gets all the parts needed yet.

The bottom end is split and the crank is out and is ready to be sent out to Powroll to be stroked soon.

the great gazoo

07-21-2011, 06:22 PM

I can hardly wait to see the "member's " finished product lol. Word @ says he's going all out on this one............

Vealmonkey

07-21-2011, 07:21 PM

Now come on, I already fessed up to having got this engine from SWIGIN for a small price. I know it's just been too doggone hot to work on anything and I haven't been up to PA in awhile. Working too much down this way, but it keeps me buying parts. Reinforced frame, inverted front end and maybe a extended HRE swinger before it's over with. I have a +2 durablue swinger, but have not had the best reports on the durablue swingers, so I may have to get one newly made. The build is progressing slowly and parts are building up in my living room! LOL I don't think Wayne wants to build this engine in the house. LOL I was going to use a set of nos 350x forks that I have, but I sort of liked Jason Halls inverted front end, so there is now a cr125 inverted front end kit being made for me. I have the forks and the brake system and the atc250r front hub and brake and I'm shopping for an axle. Just waiting for Jason on the kit, but I have to send him my 350x lower triple so he can use the stem.