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GT380 Gear Change

Posted: Sun Jan 12, 2020 4:12 pm
by Woodpecker
Hi all I have just completed a complete refurbishment of a 1972 J which has not been n the road formore than 20 years having never worked on one of these before I have had a few problems getting it running. The first outing on the road was very good, the engine was smooth and the bike felt great. The only issue (i hope) is the gear change. During the rebuild I checked the gears and all 6 engaged but on the road Changing down is difficult and requires up and down action on the change to get the gears. When static there is a lot of up and down play in the lever about 40mm. Any ideas of whats wrong?

Re: GT380 Gear Change

Posted: Sun Jan 12, 2020 8:55 pm
by malky
Did you make sure that the two legs on the gear shaft return spring were fitted each side of the pin - it's quite easy to dislodge it as the shaft is quite a loose fit

Re: GT380 Gear Change

Posted: Sun Jan 12, 2020 9:08 pm
by itsnotateapot
malky wrote:Did you make sure that the two legs on the gear shaft return spring were fitted each side of the pin - it's quite easy to dislodge it as the shaft is quite a loose fit
totally agree

Re: GT380 Gear Change

Posted: Sun Jan 12, 2020 9:51 pm
by Woodpecker
Thanks I was thinking it may be the return spring not fitted correctly as there is no spring action on the gear pedal. So it looks like side cover off to investigate !

Re: GT380 Gear Change

Posted: Tue Jan 14, 2020 9:22 am
by Woodpecker
I have removed the side cover and the spring is located corectly but does not have much spring action. I have another set of gears from a later 380 and the spring is slightly different the fork ends closer together so I have fitted this. This is my only 380 and i'm not sure what to expect I thought the change would be more switch like.
Thanks for any advice Stu

Re: GT380 Gear Change

Posted: Tue Jan 14, 2020 9:42 am
by canaletto5
Woodpecker wrote:I have removed the side cover and the spring is located corectly but does not have much spring action. I have another set of gears from a later 380 and the spring is slightly different the fork ends closer together so I have fitted this. This is my only 380 and i'm not sure what to expect I thought the change would be more switch like.
Thanks for any advice Stu
I think it possibke that the spring isn't fitted on the gear shaft correctly. You have to cross over the fork ends as they are fitted over the locating peg so there is tension in them; Kev

Re: GT380 Gear Change

Posted: Tue Jan 14, 2020 1:07 pm
by Woodpecker
Spot on Kev as you said the spring has to be pre tensioned when fitted to the change shaft, all gears appear much easier now! need some better weather for a road test. The Haynes manual is pretty poor on the 380/550.
Thanks Stu