Have a 2000 yamaha warrior with a stock 83mm piston in it. Will an aftermarket oversize wiseco piston (83.5) fit in my warrior?

 

You will have to get the cylinder bored to fit the new piston. Any machine shop that builds car engines should be able to do it for around $50.

 

A few of my buddies ride professionally and said it should fit but none of them ride yamaha they all ride honda. It's not the same?

 

No, the only piston that will work on a 83mm bore is a 83mm piston. That goes for all engines, Yamaha, Honda, Suzuki, etc. A 83.5mm piston is .5mm too big to go where a 83mm piston came out of. If you look on Wiseco's website http://www.wiseco.com/ProductSearch.aspx it specifically states on "Notes" that "cylinder boring is required" on anything larger than a 83mm. If you're looking for more power but don't wanna bore your cylinder you could always get the 10.25:1 83mm or get the 11:1 83mm (for 93 octane fuel). You will get more power from installing a higher compression piston than having an oversize piston. I would recommend a JE piston over Wiseco because they weigh less, but they only offer a 12:1 compression ratio 83mm for the Warrior, which would require running race fuel.

 

I am having a problem with my 2000 yamaha warrior 350. I was riding this weekend and about 4 miles down the mountain it shut off on me and would not turn back over. After 10 minutes it finally started back up. But this problem kept happening. Now it will not turn over at all. The battery is fully charged. Could you give me any information to what is going on?

 

Pull the spark plug and when the engine is cold do a compression check. Could be the piston could be seizing up and dying on you and cranking back up when cooled down. Plus not a bad idea to check the valve adjustment. If too tight can do the same thing when hot.Plus don't overlook the obvious such as fuel supply to the carb.

 

I had a similar problem with my 97 warrior a while back. My problem turned out to be a wire had rubbed the frame in the rear and was shorting out to the frame where the wiring loops over the frame under the rear fender.