[z400 big bore] - ATV Riders Forums - Honda, Yamaha, Suzuki, Kawasaki, Polaris, CanAm, Arctic Cat, Kymco ATVs

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z400 big bore
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Posted by: pastfast125

Theres a guy selling a high compression wiseco 92 mm piston kit, and a base gasket, I forget the brand. At 13:1, does this cause more overheating? Less reliability and in what way? And I've heard from him that I don't need a new sleeve to do this, and others have said it's bad news to do it without a new sleeve? what u guys think?

Posted by: pastfast125

would somebody answer please? I need to find out cause I would like to buy it today if there are no problems.

Posted by: AceLtz

What does the kit come with? if its just a 92mm piston then you would need to get your cylinder bored out. I wouldnt suggest doing a steel sleeve. THey have been known to be unreliable because your putting a steel sleeve in a clinder thats not made of the same metal. THat means the sleeve and the cylinder have two different heat expansion rates. The best thing to do would be to have US Chrome bore and re-nykinsile(sp?) your cylinder. THe 13:1 compression wont make it overheat or anything, you just need to run race gas. by the way, how much is the guy asking for the kit?

Posted by: pastfast125

he wants 60 for the whole piston kit and a cometic I think base gasket....so I have to get a sleeve, I can't just bore it out and put the piston in?

Posted by: pastfast125

o also would this make my Z a 426? or 416 or what?

Posted by: AceLtz

If you just bore it out and stick the piston in its going to scrape the hell out of the cylinder. You can either put a sleeve in or Get a nikasile coating. The Nikasile coating is a little more expensive but its better than the sleeve. its a 92mm piston though, that will get you about 15more ccs. Thats just an overbore piston. If you want a big bore kit, like 440ccs then you need a 94mm piston

Posted by: panteramatt

Just get it bored and recoated. I think its like $250 and thats a good price on that piston if its new.

Posted by: dads400ex

Or you could buy my cylinder and get a piston and gaskets and have a 440

http://www.exriders.com/vbb/showthr...threadid=200511

Posted by: pastfast125

can't really afford that now I don't think. I want it, but can't affor dit...lol, if I get that money I'll let you know,.

Posted by: diangelo#67

dude you just said the magic words "I can't afford it right now"
tell yourself that every time you want to buy a 92mm piston for your 400...thats nothing mine is a 95.5mm piston and i raced it for the whole year then recently tore it down the thing was perfect, wait til you have the money to go with the big kit it'll save you from kicking yourself later