I finally got around to taking the head off of my quadracer. What i found out is that i burned a hole through my piston. That is caused by a lean condition correct? Now to my choices. Should i get a new piston/ bore on my current cylinder or should i buy a whole different top end? The main question is how much would it cost to get it bored to the next overbore. Also how should i go about taking the cylinder off of the quad because the piston is seized tight in there? Thanks

 

you have a lean condition from something. diry carb or leaky crank seal. you have metal in your crank so you should split the cases and have it bored anyways. this is gonna be time consuming if you know how or expensive if you dont. we just did two quadracers both took about ten hours each any questions ask

 

How much damage was there. If none or very minimal there is no point in getting a new top end, just have it bored out. Also, are there many or any shavings in the crank area? Often when a hole gets burned through the piston, the aluminum is melted and gets shot out the exhaust. Look it over real good and clean as much as you can before decided to pull everything apart. My brother has melted a piston and didn't split the cases, just cleaned really good, and he had no problems.

 

it could also be spark plug also because i know that running a to hot of a plug can cause it to pre-ignite. i have tried all different kinds of plugs and the best one i have came across is NGK B8ES.. and like the others said you could be running lean also...

 

Thanks for the replies. Is there a way that i could just suck out the shavings in the crank with a shop vac or blow them out with an air compressor? How much would it cost to have it bored out? Also how do i go about getting the piston out being it is seized? Thanks again I dont know what i would do without you guys.

 

Try tapping the piston out. You can try blowing the shavings out or vacuuming, but like I said, make sure it is totaly clean. Bore jobs are around $50

 

Bad news guys....it wasnt the top end that was seized its the bottom end. I think im just going to give the engine to a shop and tell them to fix it. I know i will pay out the *** for it but it will be less hassle for me. Thanks for all the help.

 

Well, this will cost you about $600.
You may consider buying a running motor from ebay

 

That is assuming there is nothing in the bottom end that needs to be replaced. I spent about $650 on a top and bottom end rebuild (trued and welded crank with new rod and bearing, piston kit, bore and hone, milled and resquished head, new bearings and seals). I also had to replace 3 shift forks and repair a stripped drain bolt that ran another $220.

 

I was refering to a bottom end rebuild alone will cost around $600. I was going to change the bearings and seals on my motor, and local shops were gonna charge $400-$800 The top end will cost another $200. The more you can do yourself, the better