Maybe someone out there can help me with my problem.
I just put a .60 over Wiseco 10:25/1 piston in a 88 XR200 motor that had Powroll's stroked crank in it. I was running a 120 main jet and 92 octane, the balance of the engine is stock with the exception of a ATC big fin cylinder.
When first running the motor I could hear a little rattling off the bottom which I thought it was the timing chain. It also had a real kick at TDC when starting.
I broke it in properly and in my first harescramble with it, started overheating and finally blew part of the crown off the piston just off the to the side of the intake.
When examining the piston it looks like a lean condition with the burnt /melted aluminium dusting on the top and the heat score marks on the side.
Is a 120 Main too lean, it seemed to run fine with this.
Do I need higher octane fuel.
Is .60 over to much for these cylinders, I'm using a big fin ATC cylinder so I thought the .60 over piston listed for ATC would be ok.
Someone must know about this.
I appreciate your time.
Kelly
I just put a .60 over Wiseco 10:25/1 piston in a 88 XR200 motor that had Powroll's stroked crank in it. I was running a 120 main jet and 92 octane, the balance of the engine is stock with the exception of a ATC big fin cylinder.
When first running the motor I could hear a little rattling off the bottom which I thought it was the timing chain. It also had a real kick at TDC when starting.
I broke it in properly and in my first harescramble with it, started overheating and finally blew part of the crown off the piston just off the to the side of the intake.
When examining the piston it looks like a lean condition with the burnt /melted aluminium dusting on the top and the heat score marks on the side.
Is a 120 Main too lean, it seemed to run fine with this.
Do I need higher octane fuel.
Is .60 over to much for these cylinders, I'm using a big fin ATC cylinder so I thought the .60 over piston listed for ATC would be ok.
Someone must know about this.
I appreciate your time.
Kelly