? about making my 300 a 330

[signguy]

how hard is it to do this yourself...also how much does it cost in parts. if i had some one do it roughly how much would it cost

[quadmad123]

if i was you i would by a bore kit,then if you took it to a engine place they will drop it straight on top....it will cost about £300

[bradley300]

if you have a press, you can do the whole thing yourself. if not, you will have to have the sleeve pressed in

[bwamos]

Basically if you have to ask.. get someone to do it. ;)

I'd reccomend Four Stroke Tech. They do a great job IMHO. Been running my 330 for 5 years.. with your normal high performance maintenance.

[300ex13]

uhh id find a machine shop near you to do it...cheaper and closer to home....

[bwamos]

Don't know about you but I dont trust just any joe blow shop to do my valve & port work.

I HIGHLY reccomend head work if he goes with a 330.

FST, DASA, Sparks are all engine builders that I would trust with a 330. I would not trust the local shop unless they are VERY reputable with building/modifying motorcycles. The loal shop will usually cost you more anyway.

[400ex28]

Originally posted by 300ex13
uhh id find a machine shop near you to do it...cheaper and closer to home....

I think he was just talking about getting the sleeve pressed in and out. not valve work and the whole shabang,.

[bwamos]

Aye.. but a 330 IMHO isn't worth it without head work. Without headwork stick to a HiComp True 300 or high comp stock bore. Then I'd do it local.

HiComp 300 will keep you in the sport class too.. if you decide to race. ;) 330 puts you in with the 400ex's and 450r's. At least around here (MO Hairscrambles).

Without headwork, I think he'll like the true 300 much better. And go with 11:1 of course. Don't need a new sleeve for the 300 either. ;)

[signguy]

just changing the piston will make it a 300 where do i get the piston.... also is it easy to do?

[Mickey Dunlap]

I put just a 330 kit in one of my 300ex's just to get some power for a weekend ride with no other mods but a pipe and it made a real fun torque monster out of it. Later I put the cam in for more top end.:)

[bwamos]

You can buy the piston from almost any ATV parts supplier.

White Brothers, Dennis Kirk, etc... should all sell an 11:1 compression 76mm piston for the 300ex. That will be a 2mm overbore aka. 0.080" over.

Weisco should work fine for you.

Most of the engine builders will sell you the kits for it as well, ike FST. They will be able to tell you and send you the gaskets, etc you will need to replace as well.

For the 297cc (true 300), you will need to get your existing sleeve bored at a local shop. Or you can UPS it to one of the engine builders, and they can do it just as cheap if not cheaper IMHO.

I shipped the entire upper half of my engine, carb, & CDI from Missouri to FourstrokeTech for $19 FedEx (insured).

[signguy]

my 300 is still new less than 40 hours on it do i still need to have it honed

[bwamos]

Yes.. anytime you change the piston/rings you need to get it honed. The rings need an unpolished surface to rub on so they can seat properly even if you replace with a stock bore (282cc).

If you're looking at the 300 you're gonna need to get your sleeve bored out anyway.

Also as a side note, no matter what you change. High compression stock bore all the way up to a 350cc+ you're going to have to rejet your carb to match the new fuel requirements.

[signguy]

so you think the 300 is the best bet.. what else should i do while i have the engine apart...cam...? im just worried that the 300 piston wont be noticeable

[bwamos]

If just make sure you get the 11:1 compression version.

A cam works well with the higher compression. A Hotcams Stage1 or Stage2 will work great. Webcams are also great.. but you need to get your rockers hardened for them.

If you replace the Cam get heavier valve springs. Easy to replace and cheap (like $20). The 300ex springs are pretty wimpy.

When you have it apart, you'll need to make sure you dont have much wear on the rockers. If you do have a noticable amount of wear on the rockers, you'll want to replace them along with the cam. The rockers aren't very expensive either.

The 300 (296cc) is going to be a 76mm piston. (2mm / 0.080" overbore).

The higher compression piston is what's gonna give you more power. Dont go over 11:1 though, with air cooled engines beyond that point you have to start dealing with race fuel. 11:1 will run on premium pump gas.

You should see about a 10-20% increase in power over what you have now.

You do have aftermarket pipe and filter, correct? I'm assuming that you do. If not.. that will definatley be your first step for more power.

[signguy]

yes on the pipe and filter any machine shop should be able to bore and hone the engine right should i buy the clymers manual to do it right . i mean ive never done any engine work but im pretty handy

[bwamos]

Yes, and yes.

The clymers manual will be your best friend.

Just make not that the head cover bolt torque specs in the manual are wrong.. it's a typo. It says 17 ft-lbs. It should be 7 ft-lbs. The 10 or so small bolts that hold on the head cover. Not the large head bolts themself.