305 cc kit?

[300EXroostking]

I've heard that u can bore a 300 over .80 and make it a 305. Is this true? I really want to get a high compression piston bored out a little bit but my pop says he doesn't want me to cause "there's no reason to tear down that motor". Will the 305 give me good power with 11:1 compression? How would it comppare to a 330? Thanks

I herd the 305 will stay with a 400ex.
I also herd the 330 will beat the 400ex.
And that the 390 or w/e size will kill the 400ex.

I'm saving right now for the 330big bore kit.
I'll tell you how I like it in a few months.
(Mabe x-mas)


Zack.

[Red Rooster]

I don't think that just the piston, filter, and, vents are gonna make you stick with a 400ex. It will take that + pipe, cam, and valve springs.

Correct. More comp. doesnt mean your gonna beat
a 400ex. When you get the kit you will need to
get valve springs/cam/rev box/pipe/...ect.


Just the kit doesnt mean you will beat it,
theres other mods you need,
the bigbore kit is a start.





.02

[300EXroostking]

Well, i already have a white brothers pipe. white brothers powerfilter, uni airbox vents and i'll prolly be gettin a header before too long. I think that these mods and the big bore would be pretty fast. I'd have to wait a while before i got a cam andvalve springs. Do you guys think it would run too hot or that anything will break because its on its last bore? Thanks

[Tommy 17]

i heard wit any mod to ur 300ex u have to buy a rev box but on a 400ex u don't have to untill u get a 440 kit. i am sticking wit my stock rev box on my 400ex wit the 406 kit.

True, i herd you need rev box, and an oil cooler, to keep the engine running cool, i think they are like 150-200$ for both.

Can the local shop just bore it out without a new cylinder?
And just put a bigger/hi comp. piston in it?
Thanks.

[stocktires]

yes, i your local shop has the boring machine they can install the piston. you WILL need a high rev CDI!!! just with my complete exhaust it hits the rev limiter BAD! with cam & springs you wont come near a 400! you need a 330, ported w/ oversize valves, big billet cam, 330 exhaust (sparks is AWESOME) and oil cooler ect ect to stay with or slightly beat a 400! isnt not worth the money, just go buy a 400!!!

I would reccomend the 11:1 305, with hardweld drop in cam, rev limiter, heavy duty clutch springs, and oil cooler! after that a 400ex or 32mm mikuni carb!

[DEAL]

If you're gonna increase the size of your motor, you are better off re-sleeving it.
The more you bore the stock sleeve the thinner it gets ; thus less reliable.
Where as with a 330 kit you get a new sleeve and don't have to worry about the problems you would have when boring the stock sleeve.
So i say you are better off saving a little cash and getting a 330 kit, it will be alot better in the long run than just boring it out.

How much for all that you listed?????????

[quadfamily]

I'm kind of where you are at right now 300EXroostking. I just bought a .080 over Wiseco 11:1 piston from Four Stroke Tech for around $110. Then I got a White Brothers drop in "all around" cam and Kibblewhite HD valvesprings with Titanium retainers. The thing is I don't think .080 over makes it a 305cc. I think it ends up around 297cc or something close to that but i think it's still under 300cc. Not that it matters too much. Here's the things I already have on my bike: Curtis sparks advance timing flywheel key, Powroll large diameter Head Pipe, K&N filter, Airbox lid cut open with an Outerwears airbox lid cover, Choke plate & shaft removed(makes a nice increase in power if you re-jet for it), Re-Jetted, 20" rear tires and 14T front sprocket and 38T(stock size) rear sprocket. I'm not too concerned with taking my stock sleeve to its max overbore for two reasons, 1.) Fourstroke Tech has tons of stock sleeves and he said he could sell me one anytime I want for like $20. 2.) If I'm not happy with this setup or whenever it wears out I would probably get a 330 kit anyway.

What does taking the choke out do?

[Lil90man!!]

it opens up the carb and allows for a hair more flow

[quadfamily]

like lil90man said, the choke parts are in the path of the airflow through the carb. They are a restriction even when the choke is not on. When you remove the choke you remove the restriction thus increasing airflow through the carb. It's very easy to remove.

[300EXroostking]

I'm pretty sure i saw on the rides section some1 that had a 300 bored over .80 and they said it was a 305. I may be wrong though.