Shift Forks wear ?

[buzzawak]

Hi all,
I am rebuilding my first 600 engine and into the gear box, all looks good but will replace all the bearing as matter of course. Find it stupid that Yamaha does not provide any specs for the shift forks other that saying replace if worn.

The shift forks don't have any obvious signs of wear but I was wondering how thick should the fingers be at the contact patch? Or when the shift fork is in situ what would be the max recommended freeplay?

Please dont reply with "if unsure replace them" I dont the the money to waste.

Thanks in advance.

[yamaha_george]

Hi all,
I am rebuilding my first 600 engine and into the gear box, all looks good but will replace all the bearing as matter of course. Find it stupid that Yamaha does not provide any specs for the shift forks other that saying replace if worn.

The shift forks don't have any obvious signs of wear but I was wondering how thick should the fingers be at the contact patch? Or when the shift fork is in situ what would be the max recommended freeplay?

Please dont reply with "if unsure replace them" I dont the the money to waste.

Thanks in advance.

Yamaha do supply that info but ONLY to their service houses although I am told by our American cousins these books are availkable to the general public there but my 3 local dealerships deny that in the UK.as was my experience when I ran the Yamaha service center back home it was in house publication only and you would lose you accreditation if caught distributing ! ( photo copied all our and the originals locked in a fire vault and even that was frowned on until I pointed out that their last shipment of requested books took 5 months to arrive and WTF was I supposed to use in the mean time after that we got a 5 day delivery from south america instead LoL.

[buzzawak]

Thanks George for the reply,
Pitty this information isnt release into the public forum seeing that the bike is now so old. Do you have any suggestions?

Yamaha do supply that info but ONLY to their service houses although I am told by our American cousins these books are availkable to the general public there but my 3 local dealerships deny that in the UK.as was my experience when I ran the Yamaha service center back home it was in house publication only and you would lose you accreditation if caught distributing ! ( photo copied all our and the originals locked in a fire vault and even that was frowned on until I pointed out that their last shipment of requested books took 5 months to arrive and WTF was I supposed to use in the mean time after that we got a 5 day delivery from south america instead LoL.

[reelrazor]

Ehh, if they show any sign of heat (discoloration-reddening/blue-ing) at the tips, that's a good indicator that they are past their service life.

Comparing each fork against the other two is a good way to spot any flaw/issue.

And, I have found that wear occurs(and is more of a problem) at the shift drum end of the fork as well as at the tips. This can be touched up by welding and re-grinding.

And furthermore....seriously look at the shift fork shafts-to the point of using a machine shop's surface plate and make sure the forks slide on the shafts with absolutely NO binding.

Think: --------> slides all the way off under it's own weight when shaft is tipped