Hi. Still have knocking sound. Tore motor down. Crank bearings are good, rod bearing is good. Wrist bearing is tight. Can anyone help me with the piston to cylinder wall clearance? Had a friend who is a machinist mic the piston and cylinder at the wrist pin of piston and center of cylinder. Came up with 4.5 to 5 thousands clearance. Can anyone tell me what the clearance should be? When putting just the old ring in cylinder I have about 3 thousand ring clearance. I don't have a service manual. Dealer not much help. Can anyone help with specs? This is a 2001 250 Trailblazer. Thanks for any help.

 

yeah i don't know what a 2cycle is but yours is 2-1/2 times my 4 cycle LIMIT of 2 thou,STANDARD CLEARANCE IS a half a thou.-- thou+1/2 at most.i don't think you should be running that loose even for a 2cycle.....get some specs at another dealer...

 

Piston Clearance-Standard .0011"-.0021" Limit .006"
Ring End Gap-.009"-.018"