What 350x motor mods?

[Roland]

Hey, I own a 86 350x runs great...but I want to give it more power.... I have about 1000 bucks to spend...what options do I have ...please be detailed in what and how its done..(it will be done at a local shop but, I just want to know whats involved).I do not have a clue when it comes to this...always just rode stock machines...as far as cams valves high comp pistons, what kind if any machining needs to be done?...I do not want to run race fuel...I guess if you had this trike and a grand to spend what would you do?

[RIDE-RED 250r]

Get ahold of Mickey Dunlap. Here is his website http://www.fourstroketech.net/#!__pr...vstc1=atc-350x

But there are a bunch of unanswered variables here... Like, does your X already have a performance exhaust? Do you know for sure if it does not already have a performance cam and/or high compression piston? What condition are the valves and valve seats in?

But aside from that, if I had a 350x that was bone stock front to rear and had $1,000 to spend, here is where I would start...

-Wiseco 10.25: piston and fresh bore job, roughly $250 total. Breaks down to $150 for the piston, and $100 for the bore job on average
-Replace valves, valve guides, and have the valve seats ground. Not sure on what new valves go for for that model, but I would guesstimate total with labor to be around $300, possibly more depending on what brand valves you go with
-Full DG exhaust, that runs about $250. Or better yet a DG header with Supertrapp silencer. That would bring exhaust closer to $500
-If you go cheaper with exhaust, you should have enough to buy a good performance cam. That's going to run $200 or better.

Now that was just a list of parts. If you need to have the work done at a shop, then you would need to cut your parts budget nearly in half to cover the labor.

It's easy to want to jump right into high comp pistons, cams and whatnot. But if the valves are old and worn then all the money you will spend making more compression will be for naught. It's easy to spend alot of money on this stuff, especially with thumpers.

[zappaz]

if yr goin into the head after yr valves are removed mite as well get the dremal out and polish yr intake ports the with a roto zip blade open up yr exaust ports after ya ger a good clean look in the intake a wire brush will cut sum nice spirals in it and of corse the shop that regrinds yr seats should check to c if its tru and deck it if it aint

[Roland]

thanks red ill get in touch with him...and as for exhaust its not stock but I am not really sure what it is ill get some pics up....might be a old cobra system...zap is that something a good shop should just check and clean or do I have to ask for that if i get new valves and valve seals?

[Poco Loco]

If you want some sheer grunt, resleeve the cylinder with a 500cc cylinder from LA Sleeve. The stroke will be shorter so it will be a 420cc. You can choose your compression ratio to match the fuel you would like to run. You will still have $$ left over for a K&N and a pipe......There is no replacement for displacement.

[Roland]

other question I have ..will these mods hurt the integrity of my motor or shorten its life? I run up north in NYS tugg hill area....ride 100 mile plus days now on it....will it remain that reliable?

[RIDE-RED 250r]

It should remain reliable if the work is done right.

Poco Loco is right about displacement. But I disagree with jumping right into a big bore without first making sure everything else is up to par, especially in the head. If your valves are original, and the head has never been touched as far as re-grinding the valve seats, adding more compression and displacement will only make valves that are likely to be blowing by to at least some small degree that much worse. Plus going with that 420 big bore, you will have to have the cylinder head combustion chamber re-chambered for that much larger bore. If you don't, you will have a sort of "shelf" protruding into the cylinder instead of an even transition fro the top of the cylinder into the head combustion chamber. Having a grossly improper squish band area will give you problems a plenty.

IMHO, you need to make sure the base engine foundation is up to par before doing more extensive mods like big bores and such. Which is why I recommend a complete valve job and basic bolt-on mods first.

Then if you want to go big bore, I would definitely get the crank rebuilt.

BTW Roland: I ride Tug Hill too. Wereabouts do you live in CNY?? We may have met up there...

[Roland]

I live in stockbridge ny It is just outside Oneida Ny...

[RIDE-RED 250r]

I know right where that is... Not far from me just south of Camden.....

[Poco Loco]

When I did my big bore 350x to a 420cc the squishband was not an issue. I know its important on the 2 strokers though.

[RIDE-RED 250r]

When I did my big bore 350x to a 420cc the squishband was not an issue. I know its important on the 2 strokers though.

Ok, but Im guessing that a 420 bb piston has to be somewhere north of 10mm larger in diameter than the stock size. WOuldn't the edges of the combustion chamber protrude into the cylinder? I would think for sure rechambering the head would be necessary with a big bore sleeve and piston..

[Mickey Dunlap]

Hey, I own a 86 350x runs great...but I want to give it more power.... I have about 1000 bucks to spend...what options do I have ...please be detailed in what and how its done..(it will be done at a local shop but, I just want to know whats involved).I do not have a clue when it comes to this...always just rode stock machines...as far as cams valves high comp pistons, what kind if any machining needs to be done?...I do not want to run race fuel...I guess if you had this trike and a grand to spend what would you do?

The 350x is a bullet proof motor,even fully race built. For what you are looking for I take a Wiseco 12:1 piston,either std bore or .040 over if it needs bored and reshape the domes for better flame travel and to knock the compression down to run pump gas with my cam. With the higher compression I can run a bigger cam the other companies so you get more power for the buck. The bigger cam also bleeds off cylinder pressure along with the lower compression to let you run pump gas safely. For the type of riding you are doing this is really all you need,plus it keeps the cost down so you can get it all done with labor for the $1000 you have for the job. That would include valve job,valves gaskets,bore job,piston kit,cam and valve springs. http://www.fourstroketech.net/#!__home

[zappaz]

i used a shop when instaling / removing valves only charge me $35 and thay check to make shure the head is tru and grind n seat the valves to save their name id belive all head shops check and corect theise no one wants sumone complaining about their work and it only takes them a min to do this ''thay have the right tools '' now hogin the exuast
and polishing the intake thats sumthing u can do while watching the evening news dnt take long and lets it breath so much better the guy at the small engin shop can pop em in and out but i go to the head shop