200x 83'-85' head flow numbers.

[Mickey Dunlap]

Todays flow numbers for the 200x 83'-85'

When people talk about porting their heads it is very important to flow the heads before and after each mod. As you can see the (Up-Front Racing, my Dads business) Powroll head off my Team Honda 200x at one point my Dad must have replace the valves, but he didn't have a flow bench at the time and he didn't put a 30 degree back cut on the new valve and he missed out on a good amount of flow. This is why if you send your heads out to be ported ask if they have a flow bench, and if you can have the before and after flow numbers.

209249

[Dave8338]

GREAT info, Mickey ! Just looking at the data, depending on where your lift numbers are at, you can gain about as much as going to the 2mm over sized valve, with a 2-step drop on the cam.

[Mickey Dunlap]

GREAT info, Mickey ! Just looking at the data, depending on where your lift numbers are at, you can gain about as much as going to the 2mm over sized valve, with a 2-step drop on the cam.

It depends on what the cam is. Most members don't even know what they get from a cam grinders off the shelf cams. And most off the shelf cams are so mild you really don't get what you pay for. I have a few of Webs off the shelf cams to degree in Friday to see how they come out against my old Powroll race cam. Then I'll start building a cam for my 253cc motor kit.

[Dave8338]

Looking forward to what you find out. All eyes and ears. Are you going all out or putting something together for an all-rounder ?

[Mickey Dunlap]

[QUOTE=Dave8338;1351616]Looking forward to what you find out. All eyes and ears. Are you going all out or putting something together for an all-rounder ?[/QUO

I have a good 20hp all around good kit already, but I want to build a monster for my self and maybe the project 200x for ATV on Demand.

[aramid]

.
Your chart is xlnt.

The 30 degree back cut intake is a very old school racing trick and it helps most at the lower lift numbers . . Once the valve is opened a certain distance, the effectiveness of the back cut is almost nill . . I was doing that on car engines back in the 70’s . . The flow increase at around .150 lift and below in the intake is not very important due to the physics involved but more is still better than less . . The increase with the big valve and back cut is xlnt and I'm guessing that you kinda wish you had that flow back when you were racing . . I would have liked to anyway.

It has been found that back cutting a stock type automotive exhaust valve can actually reduce overall flow in some cases . . I have test results from a stock exhaust valve and Ferrea valve, and the stock one flowed more overall . . I was a bit surprised but it seems to be that the longer face of a stock valve directs the exhaust gas in a more upward direction [which is of course more directly towards exhaust port] than a back cut one in some cases.

As you may know, you can also pick up a little flow by doing at least a 3 angle cut on the valve seat and preferably a 4 angle one with the 4th being in the throat of the port.

You can also pick up a hair by locating the contact area on the valve on the stem side . . This provides the least amount of obstruction by the valve upon its initial opening.

Have you done any testing with back cut exhaust valves?

[Scootertrash]

This is why I love this site. While I may not be able to use (or want to) the type of mods here, I can pick and choose my level of improvements. YOU GUYS ROCK!!!!!

As I explained to a buddy who likes to give me grief about the time I spend modding trikes: "It's not that I necessarily need it, it's there if I want it" ;)

[Scootertrash]

Just so I have something for reference, what is stock 200X hp? :wondering

[Mickey Dunlap]

Just so I have something for reference, what is stock 200X hp? :wondering


I'll let mike, I mean aramid answer that.

[yaegerb]

Just so I have something for reference, what is stock 200X hp? :wondering

13 if I remember correctly.

[Dave8338]

Thinking around the 16hp @~ 8,000RPM mark.

Could be wrong...

[Ol Deuce]

Mickey: is the CC of the 200x head the same as the 185s head?? Ol Deuce

[Dave8338]

Mickey: is the CC of the 200x head the same as the 185s head?? Ol Deuce


Build it... BUILD it... BUILD IT ! ! ! ! ! ! :shiftyeyes: :D Yes............................................... .................................................. .................................................. ........................

[Mickey Dunlap]

Well on the Powroll dyno it's 11hp at 4000 feet in Bend OR.

Yes the cc's are the same, the only thing different is the casting numbers, and some casting flow better or are better to work with because of the placement of the seats is just a little different.

[oscarmayer]

under testing and flow bench usage the shop i use for doign all my porting has spent years doing cnc valve seat cutting work as well as valve itself cuts. they have found some of the best angles by doing multiple different shapes and cuts testing to see what works best. cutting the surface of the valve alone is yea an olf school trick that does help some. BUT working the seat as it should be is a totally different animal. You can increase nearly 25-25% of flow over stock by just working the seats and valve face itself. Then with porting we have seen as much as upwards of 35-40% increse on Honda race motors. (these are car motors but the principle still stands).

the 30* angle does help, as mentioned more so for the lower end, but every but helps. I do not agree that that doe not help in the upper RPM ranges. a angle cut to make the air flow better into the chamber is always going to be better than a flat 75* angle like most stucks are. the 30* helps round the corner some and thus promotes better flow.

also what works on 1 head does not always work on another exactly the same. castings shift, porting by hand is not 100% consistant and this there will always be tiny bit of differences. over all as Mickey mentioned, always make srue your porter has a flow bench to back up his claims and proves before and after flow numbers. if he does not or will not, FIND a new porter...

Good luck out there and awesome info Mickey.

[oscarmayer]

stock HP on these were not as much as you guys think. most were around 9-11HP. today's chinese 200CC motors that are remakes fo the old honda stuff but have higher compression are barley touching the 12-13h mark. so I would get 11 hp would probebly be about right for the 200x in stock form.
getting 18hp out of a 200x is a big deal (we are talking wheel power not flywheel). getting 22hp range means a ton of work and stroking was done usually when proeprly dynoed by a dyno that is set "correctly" not to fudge numbers. Mustang and dyno-dynamic dynos are load bearing and thus provide a much more accurate results. Others are not load bearing and are ususally reading about 12015% higher due to inaccuracy of the dyno by not having a load.

[Mickey Dunlap]

Yes every head is different. I get a lot of Yamaha Warrior customers that want big valves. A long time ago I tried a 900 Kawasaki street bike valve in them because it fit right in. I told this to Kibble White so now they sell them. What I didn't tell them is they killed the flow. When I tell customers this they don't understand that the stock valve flows more because of the back side shape. They want it anyway, so I have to tell them I don't want the job then.

[Dave8338]

I see these numbers and have always wondered why, so few details about the specific hp and torque numbers, are available.

Take a look at the spec sheet for a 1983 XL200R Enduro bike. Same basic design principle, engine parts, etc.

Max Power
18 hp @ 8000 rpm

Max Torque
1.7 kgf-m @ 6500 rpm
http://www.motorcyclespecs.co.za/model/Honda/honda_xl200r%2083.htm

Which set of numbers are wrong. Where the above stats using HP at the crank?

[xrider]

The last time I had my 200x on the dyno it put down 27 hp at the wheels. Thats with extensive head work, a +6mm long rod stroker and 12:1 compression.

[Dave8338]

The last time I had my 200x on the dyno it put down 27 hp at the wheels. Thats with extensive head work, a +6mm long rod stroker and 12:1 compression.

I would believe that. I am MUCH more familiar with motorcycles and how to get power out of them. A 200cc engine only making 11-12HP and extrapolate that out to a four cylinder 800cc bike and you would have a 48HP inline four ? ? ? Yes... I know the math doesn't work that linear, just making an example.

[Mickey Dunlap]

I see these numbers and have always wondered why, so few details about the specific hp and torque numbers, are available.

Take a look at the spec sheet for a 1983 XL200R Enduro bike. Same basic design principle, engine parts, etc.

Max Power
18 hp @ 8000 rpm

Max Torque
1.7 kgf-m @ 6500 rpm
http://www.motorcyclespecs.co.za/model/Honda/honda_xl200r%2083.htm

Which set of numbers are wrong. Where the above stats using HP at the crank?

I would say those are crank numbers.

[Mickey Dunlap]

The last time I had my 200x on the dyno it put down 27 hp at the wheels. Thats with extensive head work, a +6mm long rod stroker and 12:1 compression.

Those are very high numbers, that's why I wanted to take yours and mine to the dyno I use. Now I'm just going to take mine with a good head on it because I know where it was and that will give me a idea how these Dyna Jets work compared to the Powroll dyno.

[Dave8338]

I think you're correct, Mickey. Be interesting to have a cam out of one of those, to run numbers on. Same as the ATC ?

If it is at the crank, and others have stated that 11 RWHP is what is to be expected, that means that there is a ~ 40% loss in the drive train. This I do not believe.
Any average that I've calculated and observed on several projects from 2 to 4 wheels, puts the RWHP losses in the 15% range.

The bore and stroke numbers, match what I have going, the XL compression is lower at 9.2 :1 and the XL carb is a 24mm Keihin.

[xrider]

Those are very high numbers, that's why I wanted to take yours and mine to the dyno I use. Now I'm just going to take mine with a good head on it because I know where it was and that will give me a idea how these Dyna Jets work compared to the Powroll dyno.

That should make for a good comparison to the powroll numbers. Mine was on a Dyno jet as well. Curious to see what kind of numbers you pull if you put together a big bore / stroker combo. I am still bound determined to break the 30 HP mark.

[xrider]

Mickey, How much of the 253cc will be stroke and how much will be bore? I'm assuming 6mm on the crank?

[ironchop]

while I was already aware of the fact I had very little understanding of flow when I began cleaning up some casting flaws in my intake track and incorrectly referring to it as "mild porting", I must now humbly admit that I didn`t know just how friggin ignorant I was to what is involved after reading this thread. I did study camshaft theory (a little) and had several calls in to the Megacycle rep before I bought that cam but I think it`s time I STFU and learn more before I attempt this again.

I deserve to feel stupid for not asking more questions of more experts and now all I want to do is tear down my X motor with four hours on it and just send it off and quit pretending I`m doing any good at home on a workbench with my grade-school understanding of flow.

Thanks for sharing the info, Mr. Dunlap

[Mickey Dunlap]

Mickey, How much of the 253cc will be stroke and how much will be bore? I'm assuming 6mm on the crank?

I'm going to go a 8mm stroke with a safe 70mm bore, I could go 7mm but it makes everything right on the edge then. I'm keeping the stock rod with a super lite piston two ring style because we will be 4mm's shorter decks.

[Mickey Dunlap]

while I was already aware of the fact I had very little understanding of flow when I began cleaning up some casting flaws in my intake track and incorrectly referring to it as "mild porting", I must now humbly admit that I didn`t know just how friggin ignorant I was to what is involved after reading this thread. I did study camshaft theory (a little) and had several calls in to the Megacycle rep before I bought that cam but I think it`s time I STFU and learn more before I attempt this again.

I deserve to feel stupid for not asking more questions of more experts and now all I want to do is tear down my X motor with four hours on it and just send it off and quit pretending I`m doing any good at home on a workbench with my grade-school understanding of flow.

Thanks for sharing the info, Mr. Dunlap

It's not about being stupid, I just happen to work at Powroll and was told what to do and where to grind and where not to, but you still have to do a lot of R&D on each head. I'm just now after working on my v-twin Kawasaki's for 17 years to the point where my heads make a lot of power, more then I thought I would ever see. So it just takes time, and it's not all just about flow numbers. The 2 valve motors need all the help they can get and I still have more work to do. The only way I'm going to get any high HP numbers out of the 253 is a very big cam.

[ironchop]

two questions

I`ve had some conflicting answers from local builders about "polishing"

some builders told me NOT to make the intake runner glass smooth but maybe a tiny bit rough because of something called "fuel shear?" but that I should polish the exhaust runner as smooth as I can get it. Now I don`t know enough to say wether this applied to a two-valve motor motor or not as he builds and races newer machines with more valves. What are your experiences and did I misunderstand what they were telling me?

We used to back-cut the radius between the valve and stem on our bracket drag cars for more flow but it wasn`t a lathe cut on the valve on backside of the seat area but rather I grinded them in a spin fixture on a precision grinder making the radius between the stem and the big part (name escapes me) smaller. This is NOT what you meant by a 30 degree back-cut, right?

I like your website, BTW.

[xrider]

I'm going to go a 8mm stroke with a safe 70mm bore, I could go 7mm but it makes everything right on the edge then. I'm keeping the stock rod with a super lite piston two ring style because we will be 4mm's shorter decks.

Very nice. If you get it done and get rwhp numbers over 30. I'll get a motor headed your way.

[Billy Golightly]

30hp out of a 200x would be...:drool:

[Dave8338]

The general rule of thumb (though it is much like an oil thread...) on polishing runners is that the exhaust port and runner should be mirror smooth as imperfections only slow things down. Hot gas, move it fast.

On the intake, my experience has been this: Depending on the port size and charge velocity, it is possible for the air/fuel mix to precipitate out and form tiny droplets on the bottom side of the intake runner BUT, this also has as much to do with the shape of the port/runner and carb sizing as it does to the actual roughness or finished texture of the intake. Also air temps can play into effect. The colder the ambient air temp, the more likely precipitation can occur. My thought has always been, if the air/fuel ratio is correct going through the carb, then it is not likely to puddle on the intake floor. If things are set rich, then yes... it can happen. I would rather adjust the A/F ratio and have the carb dialed in using "known" jet flow rates that in themselves are adjustable by size, than to try correct the problem, through texture in the intake runner. Also, if you think about it, for every little scratch/depression left in the intake designed to "help" keep the A/F mixture in suspension, there is a tiny low pressure side, just opposite of that scratch, in the flow direction. That in itself, could lead to puddling.

Finish the inside with the little scotch bright type pads for the dremel, after the porting and I think you get the best of both potential worlds...

My .02

[Mickey Dunlap]

two questions

I`ve had some conflicting answers from local builders about "polishing"

some builders told me NOT to make the intake runner glass smooth but maybe a tiny bit rough because of something called "fuel shear?" but that I should polish the exhaust runner as smooth as I can get it. Now I don`t know enough to say wether this applied to a two-valve motor motor or not as he builds and races newer machines with more valves. What are your experiences and did I misunderstand what they were telling me?

We used to back-cut the radius between the valve and stem on our bracket drag cars for more flow but it wasn`t a lathe cut on the valve on backside of the seat area but rather I grinded them in a spin fixture on a precision grinder making the radius between the stem and the big part (name escapes me) smaller. This is NOT what you meant by a 30 degree back-cut, right?

I like your website, BTW.


You keep intake ports more on the coarse side and smoother on the ex just to keep the carbon from building up mainly.

From left to right, stock 200x, stock big valve, FST big valve.
209339

[greenhuman]

My new 70 engine is 70mm stroke, 72mm bore, 34mm inlet, 28mm exhaust valves.

[Mickey Dunlap]

My new 70 engine is 70mm stroke, 72mm bore, 34mm inlet, 28mm exhaust valves.


you have a 285cc atc 70?

[Billy Golightly]

Yes he does but it may not be what you're thinking Mickey...lol. It is still a 70 though (Mostly)

[Mickey Dunlap]

Yes he does but it may not be what you're thinking Mickey...lol. It is still a 70 though (Mostly)

OK I thought something was up. It's a 70 frame. lol

[oscarmayer]

yea, stroked and such I can see making in the 20's with tons of work.
the xlr200 was at the flywheel in those listings not wheel power.

[oscarmayer]

30hp out of a 200x would be...:drool:

Is that a challenge sir? ;-) did Billy just throw the gauntlet down? OMG!!!! he went there!!!

The race to see who can break the 30hp mark with a 200x. (Clock ticking)
LOL
it's on like donkey kong!!!!

The Goal: To make true 30+hp off a 200x engine in a 200x trike on a real load bearing dyno.
The Rules:
- Must be real wheel power
- Must be complete 200X bottom end. cases, trans and such. no taking 350x or some other setup and using it. be honest and fair. If we can get real 30hp out of this, we are talking tons of hits form magazines and that helps the trike community. so lets help each other out.
- Must use a load bearing dyno with posted settings (no faking altitude and no "fixed" numbers meaning no having the dyno computer adjust numbers "after the run" like some do for "corrections". that is fudged numbers. I want raw numbers posted.
- No power adders. all raw power only.. (No NOAAAZZZZzzzzzzz) :-p
- No bore or stroke limits. We must use a REAL Honda 200x cylinder casting at least. sleeving is ok no using custom manufactured cylinders or Chinese cylinders)
- Again we must keep to honest original parts. you will be asked to post a listing and spec of all your parts and maybe even photos when done. if you truly do break 30HP, You get to call your self "Da MAN" for 1 year till the next contest. No one else will be allowed to use that title on the forum.


Remember everyone this is for fun and bragging rights. We have till 2016 to make this happen. This gives everyone time to research, and get things done. plus if we do have more than 1 make those numbers and be able to call it reliable, then I can assure you, we will have a lot of people knocking on our doors.


Any Takers?

oscarmayer is first to sign up.
Who else is willing to give it a go?

Billy should we start a new thread and you sticky it?

[Mickey Dunlap]

With the way the cam grinders are it will take at least $1000 in r&d work just to build a cam.

[Mickey Dunlap]

My reverse cam for the 250x/ 300ex 4 valve head cam for the Big Red conversion took 8 months and $1200 to get it right. That's why I'm getting a Big Red next week.


I think these should be ready by trike fest and just drag race them, never seen a dyno win a race! lol

[oscarmayer]

LOL true! but ya know, Modern mags are all about the dyno crap.

[thcowboy]

Wow ive got a 200e (1982 big red) can most of that apply on my head? I know they're a bit different and cam and such but how much?

[Mickey Dunlap]

Wow ive got a 200e (1982 big red) can most of that apply on my head? I know they're a bit different and cam and such but how much?


Yes all those motors have about the same head, just a different casting number, some are a little better then other but all doable.

[thcowboy]

So they are the same? Just a different cam then?

[xrider]

Mickey are you planning to do an exhaust system to match to these motors? Not many options out there these days, unless you go the vintage route.

[Mickey Dunlap]

Mickey are you planning to do an exhaust system to match to these motors? Not many options out there these days, unless you go the vintage route.


After talking about the 200x project with ATV on Demand I think I should. He said the DG pipe was all the is new out there to use and it's not built right. To build a stepped pipe that it needs and the megaphone it should have I will have to build 100 of them. I'm getting in deep as it is building stuff that takes a while to sell. Just like the fenders, the first time I got stuck with some, then again this time 3 member back out on me so I'm not sure what I'll do. I need my inventory to turn over every 60 days or so.

[Mickey Dunlap]

So they are the same? Just a different cam then?

Yes I need to have 3 cam grinds. One for the autos, the 200x up to .080 over 11.5:1's, and then the big strokers.

[thcowboy]

Ok cool im gonna hop up my big red someday when I rebuild it, and i will port the head and get a cam for it