My 96' Warrior is in need of a rebuilding. I want to bore it out as well but not sure what to take it out to. I am thinking a 380 or so. Who makes a bore kit, and where can i find them?

 

The largest you'll be able to go in your stock sleeve will be 365cc's. This will be .080" larger than your stock piston. If you get a slightly higher compression piston (10:1) in that size, you'll gain about 15% over your stock horspower.

Check with White Brothers (www.whitebrother.com) and Powroll (www.powroll.com) for piston kits.

In my opinion, the Warrior does better with a JE, Arias or Ross Forged piston (or the stock cast piston), rather than a Wiseco. At that size, the Wiseco is flexible and has more of a tendency to smoke than the other pistons. Even if you have to pay a few $$ more, the other brands may be a better deal in the long run.

 

If you really want a big bore warrior, then you should try FST (Four Stroke Technology) as they carry one of the best sleeve configurations i have seen for this. If you do not, then the Arias will offer the best overall performance in my opinion. Make sure you match the correct compression ratio to your riding and engine requirements. The higher the compression ratio, the more torque you will have. High compression ratios will also sacrifice topend as you are creating friction in the motor, therefore reducing revs. Wiseco and JE pistons are now owned by the same people. I personally have never encountered a problem with either and both would work great for an average weekend motor while saving costs in the process. An aftermarket cam would compliment anyone of these pistons and should really be considered since the head will be off anyway. Still not happy, then oversize intake valves (Kibblewhite's are my choice) with titanium retained valve springs, de-shroud the valve guides and clean up them ports.

 

<< High compression ratios will also sacrifice topend as you are creating friction in the motor, therefore reducing revs. Wiseco and JE pistons are now owned by the same people. I personally have never encountered a problem with either and both would work great for an average weekend motor while saving costs in the process. An aftermarket cam would compliment anyone of these pistons and should really be considered since the head will be off anyway. Still not happy, then oversize intake valves (Kibblewhite's are my choice) with titanium retained valve springs, de-shroud the valve guides and clean up them ports. >>



The higher compression piston does not reduce rpm because of &quot;friction&quot; it reduces RPM because the compression makes it harder for the crank to &quot;push&quot; the piston up to top dead center (like trying to push on a tire with 50 psi as compared to one with 3 psi).

Although Wiseco and JE are owned by the same company, they use different forgings from ALCOA. The JE forging is more expensive, and has a less aggressive expansion rate. This is why you can bore in a JE piston at .0015&quot; to .002&quot; clearance, and a Wiseco requires at least .003&quot; to .005&quot; clearance.

The cam is a good idea, if it's being used with a larger piston (like the 365cc offered by www.powroll.com or White Brothers).

A quality port job will not remove material from the outside edge of the guide. This material is needed to support the valve and keep it correctly aligned in the guide bore. This is extremely important with the Warrior, since it runs a very large valve (big stem, big head), and they have no rev limiter (over-revved warriors can drop a valve easily enough with a stock guide).

Although an oversize intake valve would be a great addition to a 400cc or larger engine, it would not work well in a 370cc or smaller Warrior, unless the rider were using the bike for flat track racing or motocross exclusively (it would create losses in low end throttle response), even then, the cost would outweigh the minimal benifit (in the smaller engine).