[jet]

What are some areas of engine vibrations?

I was in the UP last weekend and the sled started vibrating. I know it was bad because the recoil handle was vibrating bad enough to hear. I did feel a different vibration in the handle bars too. Its not a rolling vibration. It did seem to have good rpms at idle and max rpm was 7500 from a starting stop but at WOT if fell off to 7000. It never did that before. The LH plug will fowl at idle if left idling for a few min. I dont know if it was ice on the primary, the primary is out of balance for some reason or the crank sliped some. I haven't got a chance to run it after it sat in the heated garage after I got back.

My sled has the BMP pipe mod, Head mod, V-force III's 78 gram D&D weights (non adjustable) and EPI spring. I also have the sno-tek torque arm. Im up two jet sizes from 430's to a 450/460 on the mains. 58 needles. Put new plugs in on the trip but it didn't change anything. The exhaust valves were cleaned and installed correctly. They are shimmed also. My sled has 2300 miles. I may have to do a runout on the crank and check the primary clutch for any issues.

Any other thoughts?

 

[zr sled head]

Sounds like more than one issue..............

-low RPM..........either a clutch issue or more likely your exh valves are not operating, pull the cover off the servo and theck the cable adjustment first.

-vibration.........best to check the crank run out first. Mine was mint on the PTO end but out 12thou on the mag end, smooth as silk with the crank straightened / welded / brand new top end.

 

[jet]

I think I'll just send the crank in anyway and start checking the other items.