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gt380 transmission issues

Posted: Mon Sep 05, 2016 5:18 am
by racerd14666
i was riding along at a good spirited clip and it made a bang and lost 5th gear while going down the road long after i shifted, made some horrendous noises while rolling at idle in gear, so i finally get around to pulling the motor apart and im shocked that i dont find anything obvious, 5th gear is a bit black but all the engagement dogs are there and have decent faces and move along the shaft just fine, and the shift forks don't look to bad, a bit of discoloration but they are straight and intact, all the bearings roll nicely and there isnt anything sloppy about the shift drum. anyone have anything like that happen to them? im trying to get her wrapped up for the DGR so any input would be great thanks,

Re: gt380 transmission issues

Posted: Thu Sep 15, 2016 2:40 pm
by Suzukidave
Its been 10 days sense your post , figure it out what made the noise and lost 5th gear ?

Re: gt380 transmission issues

Posted: Thu Sep 15, 2016 6:17 pm
by tz375
Look at the dogs on 5th gear. The burn marks on the selector fork suggest that the dogs cammed up and spat out of gear followed by dogs rattling against the matching gear.

When you have 5th gear off to undercut the dogs on both of the pair, check for end float on that gear. It may be excessive and in need of shimming. Or it may just be excessive wear of the face of the gear dogs. Or a bent selector fork.

Put the shafts back in the lower crankcase half and work through the gears to see which pair of dogs engage. Could be on teh input shaft or teh output shaft.

Check that when in 5th gear, the gear should rotate freely around the fork and when not in 5th gear, the sliding 5th gear should be equidistant from the gears on both sides and not pushed much closer to one than the other.

You will have to spin the shafts to get it too go into gear and you will be able to see dogs sliding into engagement or banging into the matching gear dogs.