My neighbour had the same failure with a wiesco piston after about 100 miles in a 580 cat a couple years ago. It seemed to be a flaw in the piston when it was made. From what i can see in the pic the other piston dosn't look to me like it was run lean.
these are kimpex but i broke a doo piston in the same spot and doo gave me my money back but on the doo the ring didnt break just the top of the piston.im now using 670 H.O coated twin ring wisecos and there working fine............... way less heat ,and forged are always stronger then cast any day
I used to run over bore Weisco twin ring pistons in my GT550 Triple 2 stroke bike... and I loved them, could clean the clock of any 750 (except the water buffalo), but now wondering about them for my 700mxz. Is there any performance degradation from running a twin ring piston nowadays? one would think there would be more resistance given today's tolerances? No? That old bike was a '74 and technology has advanced a long way since then.
What's the benefit of a Weisco twin ring piston in a sled like today's?
in the process of rebuilding mine right now talked with a doo rep and they said not to go with wiseco becasuse they are so tempermental. he said it would burn up on me within a year and i would have to replace them and rebuild completely again! screw that, i went with stock pistons which sucks because they are a lot more expensive than the wiseco's. i have been told that if you don't your sled up for a really long time with them that you increase the chances of a melt down. i have run them in many dirt bikes before and never had a problem? who knows?
strong as nails compared to cast stockers no blow by like a single ring the light weight helps engine spin 25% faster on a dyno.ask Bill Cudney he will tell you
3-5 hp gain from not having blow by.......... the 670 H.O piston is simply awsome..how my 670 ring problems have you heard of? how many series 3 problems have you seen? simple...................... also ditch the stock head i run a polar head with a shim the chamber is larger cooler
and alows piston to run with out the detonation issues of the stock head to fix bottom end bearings from burnting up on you put a ground strap on the frame and block ( case) to stop arching on your bearings, factory knows about it but there pretty quiet like every thing else...............
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