1990 Formula Connecting Rods - Snowmobile Forum: Your #1 Snowmobile Forum

TheMessinger · 10-28-2009, 07:29 PM

Would anyone have advice on how 'loose' connecting rods should be on the crank? I've removed the pistons and top-end of the engine to replace a piston and rings. However, I noticed that when pulling on the connecting rods there is some play vertically when I pull or push on the rods. Is this normal?

**smallengineguy** · 10-29-2009, 12:08 PM

They should move side to side a little, but not up and down....

TheMessinger · 10-29-2009, 05:14 PM

Advice well taken. I'm guessing there is 1mm worth of movement up and down, which tells me the needle bearings and/or the crank are wearing poorly...probably the source of why the piston rings failed and dimpled the cylinder head....

Time to weigh a lower end rebuild vs alternative engine...

Thanks. Paul

**smallengineguy** · 10-30-2009, 07:17 AM

No problem. Probably had a lot of miles on it, huh? A used motor should not be too hard to find. They made millions of them.

TheMessinger · 11-01-2009, 12:07 PM

Speedo only says 6500kms and the sled is in amazing shape (ie steering booties are still intact). Looks garage kept its whole life. Any thoughts on what a used motor should cost? Thanks

**smallengineguy** · 11-01-2009, 09:28 PM

Around $500-$600 somewhere.