300ex engine mods

[Houser Cannondale]

whats a good way to pick up the torque and just overall power on my 00' 300ex?? right now i have a k&n air filter stage 2 jet kit and an hmf silencer with white brothers headpipe. right now it runs good and the exhaust gives it a noticable torque increase but i want more. and i want to get some more midrange too what mods could i do for a fairly cheap amount of money $400 or so to pick it up? i am willing to do internal engine mods too.

[Pappy]

if you can do most of the work yourself.....a bore kit and cam will get ya where ya want to be:D

[redrider ex]

it is suppose to be faster than a stock 400

[Houser Cannondale]

yea i can do all the work myself except for boring it. which a local machinest will do that for me for 25 bucks. how about a 400ex carb?? i have heard of a few people doing that. would it work good with maybe a high comp piston and drop in cam?

[Pappy]

i wouldnt get to inventive.....the 330 kits are badass and will make your quad fly. there is a ton of info and tech help on that set up.

[Houser Cannondale]

i wouldnt get to inventive

whats that mean?? lol :confused:

[Pappy]

its like this.....there are well established kits available for your engine....with a ton of help from the people who designed it etc.

if you do a high compression piston(which isnt a bad thing) and throw a 400ex carb on it ...with some drop in cam...who can ya call for help?? lots of unknowns there. just tryin to save you some major wrenching and aggrivation.

:p

[Houser Cannondale]

true.. ya got a point there id have no idea where to start to jet a 400ex carb on a 300ex a high comp piston 11:1 and web drop in cam runin on 50/50 mix gas sounds like a good idea :p

[Houser Cannondale]

would i really need the gas?? cam 2 is easy to get around here its 112 octane (the purple stuff) i could mix it half and half with 93 i just want to make sure my engine wont preignite.

[Pappy]

well....i run that mix in everything.....the wife likes the smell:D

[Houser Cannondale]

yea haha well im only 16 i dont have a wife haha but i like the smell myself i think thats what ill do. see if i can get some kidn of package from an engine builder maybe or a 330 with a drop in cam. i figure then i could keep with the 400's a lil easier. :D

[Pappy]

yeah you will like the 330 kit.....i rode a friends and it was very impressive.

[Houser Cannondale]

cool beans. sounds like thats gonna be my next project.

[exriderdude]

hey, i see you live in ohio. where in ohio do you live?

you should try giving profab a call www.profabatv.com , they do very good work

fst has a 330 kit for $295, but it dont come with a cam. a cam will run ya around $100, + boring and all other neccesities it will run you around $500 all together.

dont be fooled by what all the magazines say about the 330. it really aint that great, it will beat a stock 400 if your geared right but thats about it. I put $1500 into my motor and it still aint enough power, for me atleast. Its alot more than a stock 300, thats for sure. But i dont know how good your skills are or anything, but if you need more than a stock 300 but dont think your ready for a modded 400, than the 330 is right for you.

[foxhonda300ex]

I forgot how much does the 330kit sell for?

[redrider ex]

:D

[Houser Cannondale]

yea its in lancaster ohio. i live about 20 min south of athens in midleport, oh. profab is like hour and a half away from me ive been there before. they are real nice people to deal with.

[Rastus]

I've been wondering about this too.

I was gonna go for a 330 or a 350 kit,I already have the cam ,the rockers and all that, I jsut need the piston and sleeve, and machining work done.

my problem is, I want suspension too, but when I get suspension, I want more power also.
I know you guys are gonna say get suspension, but it costs too much ding dang money!!! its nuts!!! I can't really afford getting suspension, thats why I was thinking of getting stuff for my motor first.

[Buzzsaw]

I just go the 316 dyno saturday and we got 25.6hp out of it at 63 mph.

[MichaelS693]

if you get a big bore kit i would get a oil cooler also cause it will run ya hotter

[jwisniew]

Whats the highest you can bore a 300 and still run pump gas wit out ruining the engine?

[Live2Ride300]

What are some good engine kits for the 300ex? Piston, cams, valves, rockers, exausts, carbs-jetting, etc?

[Houser Cannondale]

you could get a 410 kit for it :devil

[Live2Ride300]

How reliable is the 410 kit for the 300ex? Thats going up alot in displacment 118cc's!

[GT300]

I think that higher compression or milling the head make you use race fuel, not bigger bores. A 400ex has a bigger bore and runs on pump gas.

[honda250xrider]

if you just bore it and put a cam im not to sure that it will beat a 400? if u port and polish then im sure it will beat a stock 400 but anyways its you riders skill if you just leave it how it is and just bore .40 over and port and polish and cam hardend rockers high compression piston then you could be in a differnt class then the 400's so you wouldnt have to worry about racing them all you would have to worry about it racing other 300's and 250's im not to sure about the class's though on how much they allow you to bore and such

[Live2Ride300]

Ya, w/ the extra bore and more aggresive cam, you want the engine to breathe better also so porting will really open it up. Ive heard the 300ex's benefit a real lot from porting.

[GT300]

The 300ex has the 250x head on it. It already has small ports for a 250cc and its on a 282cc.

[Ride400]

buying something with a higher displacement and better frame and a arm geometry always makes you go faster

[Live2Ride300]

Thats why I could outride u on my 300?

j/p

[Ride400]

ur always *****ing about how u ride a 300 and it has no balls and the suspension sucks

[Ride400]

and yeah you probably could outride me, youve been riding longer

[nj300exr]

just got done with my engne work... high comp 11:1 .20 over wiesco piston, white briothers all around cam, itanium valve stuff, and all the nececseties... the end result 800 bux short but lots of useablke power everywhere you turn... my final thought... now that you have the basics i.e. exhaust airfilter. get your self a pair of shox..

[Live2Ride300]

nj- how does it compare to stock?

[Buzzsaw]

This 316 will eat a piped 400's lunch on the track, the woods, and through 4th in a 100yds.

[nj300exr]

it compares awsome to stock plenty of overall noticable usable pwer but like i said i think suspension first engine last now

[user101]

nice bike buzz......love the carbonfibers

[Live2Ride300]

Ya, the motor is too much for the suspension

Buzzsaw - ur quad is so awesome!

[96300ex]

buzzsaw... can't get enough of that quad man.... that thing is strait up badass:D

[Buzzsaw]

I luv you guys, I'm just keeping it real for my brother with 300's.

user101 i wished carbon fiber just good ole itp's

[Houser Cannondale]

hey buzzsaw wheres that front pic you have of your 300??

[Buzzsaw]

This

[honda250xrider]

buzzsaw300, what kinda gearing are u runnning right now?
and do u race mx, ive just been wondering if you go to 316 would you have to race with the 400's or do u still race 300's and 250's

[Rastus]

About motor or suspenion first...It would depend a lot on what type of riding you do.If all you like to do is race your friends down a straight street, or something, then suspension wouldn't be needed as much.But like MX, or cross country you would need better suspension.

You could probably get an ole' 250X , and spend some money for new suspension, and some motor stuff, and beat some bigger quads with alittle expeirience. I know this cause I beat some of my buds with mine with stock suspension.Man, they get so P'd off

:devil :D

[Buzzsaw]

Im runnig 14/38 gears, and i race in a blaster class which is 200cc two strokes to 350cc four strokes. And all so in one series take an all out quad race anything goes. Just started racing this year.

[BLURR250X]

Which would be a better setup doing a 350X conversion on my 250X or getting a 330 kit?

[quadfamily]

NJ300EXR, how do you like that w/b all around cam? Did you get hardened rockers? Do you have any port work done?

Blurr, The 350X motor would definately be much faster.

[Moded86R]

I was thinking about this today.It is funny I found this.My 300ex is torn down.I cracked the swingarm.Well it either has a cracked center case or the gasket in betweew the cases is bad.Either way I am going to have to tear the motor down.


I was thinking about sending the head and cylinder to LRD.(There the only company my dad and I have ever dealt with and we had a good experince.)Have them port and polish the head,bigger valves and different cam.They would know what springs to run with the cam and all that stuff.Also having them bore the cylinder with a higher compression piston.I am not sure what kind of exhaust.It can't be loud though.400ex carb.I might go this route very possible.That means I would have to put the R off longer though.



Or Having a local machine shop bore it.wiseco high compressions piston,WB track cam,WB valve springs and all the stuff setup for that particular cam.Again not sure on the exhaust.Use the stock carb.I might go this way to.It is just a playbike and I don't plan on racing it.


I plan on buying either a 250x or a 125 dirtbike after I get my R back togother.If I get the X it will get all the goodies.Setup for Xc.I want to be able to beat my buddies stock 400ex.