jackshaft bearing

[DAGE]

I blew apart the driveshaft bearing yesterday and I think it took out my speedo sensor, I didn't notice it at first but after awhile the sled started cutting out like the TORS was kicking in, would the speedo sensor being damaged cause the machine to cut out while I'm on the throttle?

 

[TBay Sledhead]

Jack shaft brg wouldn't cause that unless a piece fell down into the area of the speedo and the track drive shaft. Track drive brg failure will usually cause the speedo and related problems.

 

[DAGE]

sorry I mixed that up, it's the drive shaft bearing that let go

 

[Glacierrr]

Yes if bearing went and speedo sensor got chewed then no speed signal to ECU and engine will quit. At least that's what happened to me. Engine was working perfectly but when you tried to accelerate it died because no speed signal to ecu. Once I replaced bearing and bought new sensor everything was fine... Easy enough to look at sensor and see if it touched anything and got damaged.

 

[DAGE]

thanks for the input, looks like I know what the issue is

 

[hotrod]

can I take the seal off the bearing and grease it.

 

[Yamahadj]

can I take the seal off the bearing and grease it.

Yep.

 

[Blue Dave]

thanks for the input, looks like I know what the issue is

This is a very common problem. If the driveshaft bearing fails to the point where the driveshaft is not being held exactly in place then the toothed "gear" on the end of the shaft can move enough to come into contact with the speedo sensor and damage it. If this happens you should see marks on the speedo sensor from the interference with the toothed "gear".

This is a piss poor design IMO with no easy way to grease this bearing. Some guys take a dental pick and pop of the grease seal to re-grease the bearing every year. The better solution would have been for Yamaha to put a grease zerk on this bearing like the other manufacturers commonly do.