It seems that Yamaha is not doing a damn thing to fix the one way bearing on the Raptor. I work in the automotive industry and I have ordered a one way gear from Yamaha, so that one of my transmission suppliers can perform a reverse engineering of the gear.

I have read in the different forums that the root cause of the one way problem is that the gear surface, on which the one way bearing rides on, is too soft. As a result, the metal shavings enter into the sprague bearings.

I will have prototype gears in three weeks and I will get a quote for production timing and parts as well. If anyone has any other insights into the one way problem, please let me know.

RIM

 

There was a post 2 or 3 weeks ago from a place in Oregon called LA Design that was in the process of making an improved replacment and would be out in about a month.

 

There's a groove on the back of the sprags. The spring goes in this groove all the way around all the sprags. That is what breaks and creates problems. It would seem to me that somthing similar to a piston ring would work in place of this spring and be much stronger. JMO

 

The problem is the metal spring, when it lets go the sprags don't all engage and they crush under the load and the clutch slips, that then rips the surfacing to death. When working properly there is no slip. The clutch hub is not the culprit here.

A guy in Australia has a good article on his web page, he uses a nitrol rubber o-ring to replace the sprag spring with great results.

Grants one way fix

Kiwi

 

I've heard of some failing and the spring was not broken but I guess it could of been weak.

 

We repaired a Rappy last week by using an O-ring in place of the spring.
( actually two o-rings... 1/16 inch by 1 3/4 ID )

It now functions without the noise .... and seems as good as new

 

Thanks for the responses. It seems that the springs can be a secondary root cause for the problem. The rubber O-rings over the one-way bearing seem like a "bandaid" fix rather than a permanent one. But I am going to meet with couple of suppliers next week about the one way problem and their proposed fixes to both the gear and the springs.

These suppliers design and assemble transmissions for most of the carmakers and should be able to provide a straightforward "systems solution" for this type of problem - which is far superior than going to a machine shop to get a gear produced.

I will keep everyone informed of the results.

RIM

 

L&A Designs sent me the spec sheet and some pictures yesterday that I put on my site.

 

well i'm definetly gonna have to check that out.