350x motor mods

[wishmasstir]

i'm looking for a good motor kit/combination for a play/mx 250x/350x

set the chassis up now it needs some more balls

350x crate motor
has a powroll/supertrapp exhaust on it with a 250x carb

what should i buy for it???

[dork]

get a 400ex carb or a fcr 39, and use a 300ex manifold. its bigger and those carbs will fit easier in it than the 350x one. and use a 350x airboot from the airbox to the carb if you're not already. you can use a 400ex boot but you have to cut out the center of the box and get rid of the snorkel boots, but it flows the best.

once you get into the motor it all depends on how crazy you want to get, you can go upto a 97mm piston i believe, with stock stroke thats 502cc, and you could still stroke it. add a cam to work with your compression ratio and a lightened flywheel and it should rip.

[wilkin250r]

The 350X motor will respond to modifications much the same as any other motor. You can get a bigger bore, a high-compression piston, and/or a camshaft. With more money, you can stroke the crank.

One of the weaknesses of the 350X has always been the older technology of the intake and valves. The ports and valves are smaller than a 400EX, so it's very possible that it will respond well to porting and oversized valves. It won't make much difference on an otherwise stock motor, but if you have a big-bore/stroker, it can be a significant increase.

However, I don't know of many shops that specialize in 350X head modifications.

[panteramatt]

Be carefull boring and stroking that motor cause I had a 450 stroker and man that thing was horrible to kick over and Im 230#!

[notfastenuf4me]

im at the same problem i was lookin at the 393 big bore from powroll and cant decide what kit to go with the 10:1 compression wit mid range cam or the 12:5:1 wit the race cam is there any other sites that have big bore kits to compare

[Plante400]

will a 400ex motor fit? i dunno
but there is your electric start:devil:

[wilkin250r]

Originally posted by Plante400
but there is your electric start:devil:

They make electric starter kits for the 350X.

http://www.spinreel.com/goki-atv.html

[dork]

when you go real big on these motors(or any kickstart motor) you should run the decompression cable up to the bars and learn the starting drill like the yz426 dirt bikes.

TC, FST, powroll, and curtis sparks all have lots of experience with the 350x.

if you go over 11:1 you should run race gas to be safe; it also depends on your cam and squish clearance too. 10:1 will run on pump gas no problem, with more overrev (depending on cam) and less stress on the rod.

[wishmasstir]

i'm bringing this thread back from the dead ....

this quad was up for sale but now my buddy decided to keep it. i was looking at lasleeves site and there was this ... http://www.lasleeve.cc/index.cfm?event=product.display&product_ID=1238 does this seem like a good kit to buy. the motor is smoking now so i gotta tear it apart anyways so misewell make it pull the front wheels up all the time right?

[dork]

thats a good kit, FST also has lots of sizes, up to 452 on bore alone. just remember when you get real big you have to upgrade everything else to keep up. the 86mm piston kit will fit your stock sleeve and give good power.