Author Topic: Third gear  (Read 176 times)

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Rory57

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Third gear
« on: 08 September, 2019, 16:43:32 »
After just completing the Essex/Herts Air ambulance run of 132 miles on my 1970 Thunderbolt. In the last 20 miles when I changed from 4th to 3rd the lever didn't spring back into central position. If I touch it with my foot it centralised. It was ok 3rd to 2nd etc and also no problem changing up through the gears, any ideas?

Editor

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Re: Third gear
« Reply #1 on: 10 September, 2019, 16:44:42 »
The return spring is probably cracked or broken or may need adjusting. It happens a lot. Take the outer cover off and take a look. If there is evidence of it being mis-shapen or cracked, it will be obvious. If it needs adjusting then one of the legs will be standing off the pressed steel cup. This cup has a bolt hole in the centre which is eccentric to the outer dia. Just slacken off the screw and turn it until both legs touch.
Good luck
Chris

Rory57

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Re: Third gear
« Reply #2 on: 10 September, 2019, 19:24:01 »
Thanks for the reply and advice. I have ordered a new spring from Draganfly although the old one looks okay. I will fit that first if it remains the same I will try your suggestion.

Many thanks again.

Rory57

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Re: Third gear
« Reply #3 on: 13 September, 2019, 19:08:03 »
The spring arrived today from Draganfly and is different to the fitted to my bike, any ideas?

Picture attached.
« Last Edit: 13 September, 2019, 19:12:15 by Rory57 »

Bess

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Re: Third gear
« Reply #4 on: 14 September, 2019, 09:18:22 »
Hi,
    The gear change spring changed in 1966 from 68-3084 to 68-3125, both 2 coil.

Later years 1970 on, had the 57-4009, 3 coil.

https://www.draganfly.co.uk/bantam/product/11262-gear-change-return-spring/category_pathway-1423

Draganfly A65 year index doesn't show the correct spring but if you use the above link it states A65 A50 1970 on. 

I have the 2 coil fitted to mine without issues. Also your model might be a year before the adjuster was introduced, but if you have one fitted it maybe worth trying to adjust.

A couple of things to check. Primary chain tension, after prolong use the hot engine reduces tolerances and gear change can be a problem, check the chain throughout its rotation for tight spots. The gear change quadrant shaft for wear on the inner bearing surface, wear here effects the selection.

Best wishes...
« Last Edit: 14 September, 2019, 09:55:46 by Bess »

Rory57

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Re: Third gear
« Reply #5 on: 15 September, 2019, 09:58:05 »
Many thanks for for your help and information. I will order the right spring now. I have the later clutch system so cannot fit the two coil spring as it fouls it. I will have another look. I was stuck in traffic going into Harwich for probably 30 mins or so after a non stop 60 mile plus run so it was probably running pretty hot. 

Rory57

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Re: Third gear
« Reply #6 on: 15 September, 2019, 10:15:36 »
New 3 coil spring now ordered!