yamaman700
New member
I changed from an Ultimax 3 belt to a Yamaha belt today because the Ultimax was to tight on the clutches. It always ran well though. Now when I'm driving along slowly the engine will rev up around 6000 or a little higher and then suddenly upshift and my speed will increase and RPMs drop significantly. When I let off the throttle just a hair it suddenly backshifts and revs up quite high again, and the dance continues that way up and down until I am able to speed up. Any thoughts on what may be causing this?? Clutch distance and alignment are within spec. I may have to go back to the squeeling Ultimax!!
tighten up your secondary
yamaman700
New member
Thanks but I'm not really sure what you mean by tighten it up??
set it to a higher degree If its set at 60* set it to 70*. It puts more force on the sheaves
mod-it
Member
Have you checked belt deflection? The three wear bolts on the back of the secondary will wear down and need replaced over time. You can also remove/add the washers that are on them as needed to keep belt deflection correct, until you eventually have to replace the bolts. As they wear the secondary sheaves will get closer to each other and make the belt sit higher, which will also cause the squeal at idle. Removing the washers will move the belt lower into the secondary, adding them moves it higher. I'm wondering if the oem belt is narrower than the ultimax and it is sitting too low in the secondary.
Get the track off the ground with a stand and run it, you want to get the "cold" out of the track. Let it coast back to a stop, don't use the brake. Your track at idle should spin slightly, move with kind of jerky movement, or be very easy to get to move with slight help from you. The belt should sit flush to about a 1/16 above the top of the secondary. I noticed my belt starting to squeal a little at the end of last year, so this year before season I checked the belt deflection. I had to remove the washer off the bolts to get it right, and it also stopped the squealing.
Get the track off the ground with a stand and run it, you want to get the "cold" out of the track. Let it coast back to a stop, don't use the brake. Your track at idle should spin slightly, move with kind of jerky movement, or be very easy to get to move with slight help from you. The belt should sit flush to about a 1/16 above the top of the secondary. I noticed my belt starting to squeal a little at the end of last year, so this year before season I checked the belt deflection. I had to remove the washer off the bolts to get it right, and it also stopped the squealing.
tedgoesfast
New member
the better belt you install the harder the material in the belt i have no luck with a hard belt shifts to inconsistint the only thing you might do is wind clutch tighter but that will affect shift pattern the harder the rubber is in the belt the clutch has a hard time griping it
tedgoesfast
New member
why noy use a yamie belt the problem with aftermarket you could measure 3 belts and all would be differant
yamaman700
New member
Well I tried taking the spring from 70 back to 60 degrees. Better but not great. I tried putting it up to 90 degrees this didn't help either. I tried removing a shim but that seemed to make it worse again. I gave up and put the ultimax back on with the shims removed and the squeel is gone!! Also she shifts normal again. Best I can tell the Yamaha belt seems a little longer so maybe the engine had to rev up more to pull it down through the secondary. Anyway thanks for the help, time to go riding again!!