new guy, new project

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sweeney1991

New Member
Mar 7, 2013
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So I picked up a 1996 for $250 and its a little rough. I want to rebuild the top end I watched a few youtube videos and it looks fairly simple. I work on cars so im very hands on but this is my first atv. I was wondering how would I measure the piston? The guy I bought it from said it was .30 over, I just want to make sure before I order the rebuild kit. Also are those ebay top end kits any good? $74 seems like a good deal but I dont wanna spend $74 on junk parts. any input would be awesome!!! Ill have pics soon its currently at my brothers house.

Thanks
 
First thing you have to do is find out what piston is in there. Rings aren't all compatable with different mfg pistons. The piston will have markings on top. Stock piston would have P1, P2, etc. Others such as Weisco would have 66.25, 66.50, etc. Next, do you plan on putting new piston in old bore, or are you going to have fresh bore? The piston would be measured with a micrometer and the bore with either an inside mic or snap gages and mic. Dealer or good auto machine shop can do this for you, maybe free.
You subtract the piston dia from bore dia to determin clearance. If everything is well within service limits you might just do rings. If it's worn bad you should have it bored. I have only once put a new piston in an old bore only because it was less than half the service limit.

BTW
WELCOME
to the
DIRT PILE !! I:I​
 
I was hoping to keep the bore it currently has. Trying to keep the budget low. lol Ill have to see the condition of everything once I pull it apart. Im hoping to have it a good running quad for under $400
 
You need to get the bore measured to see if it is within specs.

There are no prizes for putting a new piston and rings in a worn out bore.
 
Maybe a linc to the piston kit you're talking about? That piston will cost you $74 dollars no matter what size. Boreing is $50-55. It will then be a brand new engine (so to speak) and will give MANY hours of enjoyment.
 
IIRC, WSM supplies pistons for Yammy, or maybe it's Namura. Regardless, it's a good piston, equal to stock. Many will come on and say get a Weisco. Many use cast pistons with no problems.

Be aware some shops won't or don't like to use customer supplied parts, they don't make extra $$$ from them. Just find one that will. Automotive machine shops can bore but may not chamfer the ports. Either find one that does or you will have to do that yourself. It is best that who ever measures it will be the one to bore/hone it.

Wash the cylinder with soap&water several times after boreing. A paper towel should come out "clean" when it's good to go. Be sure to oil everything well on assembly.

Best instructions will be found in a Clymers Repair Manual or in the download manual.
 
I see everyone says to do a leak down test before you just tear it apart. Where do I get everything to do it? I can watch a vid to see how I just need the tool
 
Ok just a little update. I worked on the bike today, I decided to pour some gas in the cylinder and it fired right up. carb dont seem do be pulling fuel. I took it apart and opened and closed the float and blew through it and everything seems clear. The carb was loosely mounted do you think that could be the problem? what else should i look at on the carb so make sure it will function
 
ok awesome ill put it back on tight tomorrow and give it a try. I took off the exhaust and noticed a small wear spot on the piston but rings looked alright. Is it possible to get a little more riding out of it or is it necessary to rebuild because of damage to piston?
 
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