Crank Runout?

[sno-x]

What is considered bad runout? Where should it be at?

Thanks

 

[SRXSRULE]

.002-.004 measured at the end of the crank with the primary removed is pretty normal. I think once you get past .005-.006 you start to have vibrations. Some of the 98-99 SRX 600/700's had crank problems that yamaha covered for several years. If I recall most of the yammies that had bad vibration problems checked out in the .009-.012 range. They said it was due to adding studs to the track which put extra stress to the drivetrain. Eric

 

[sled_guy]

Which sled?

If it's a Polaris 800 bigblock you'll never see .007"

Polaris calls the service limit at .0045 on their sleds. Anything over .003 and I take it apart and have it worked on.

I've seen Cat triples with .010" that still ran. You could see the clutch wobble.

sled_guy

 

[sno-x]

Thanks guys...I checked my new used bottom end and it had .0005 of runout so I think Im good..... My old one last year had .007 funny it didnt make the season lol and it is a 700 poo bottom end

 

[whittaker727]

Tighter the better. .003" or better is what I shoot for.

 

[sledmanhof]

this may sound dumb but how do you check the crank runout?

 

[kelwar]

you take the clutch off and put a dial indicator on it perpendicular to the crank and turn the engine over and watch how far the needle moves