Shifting 1st to 2nd not working right

NickZ · Jan 20, 2026

New build 1973 750, rebuilt gearbox, shifted fine on the bench and statically on the bike it goes through the gears normally. When riding it under power it goes into first gear no problem, but when I try upshift into 2nd, it feels like shifter isn’t catching anything and there is only spring resistance moving lever fully up or down. Occasionally it will work right and then shifts fine up thru higher gears and down shifting. No problem finding neutral. I can sort of force it to work by letting the clutch out a little while attempting the 1st to 2nd shift.

NickZ · Jan 20, 2026

I have adjusted the primary to be sure it is not too tight.
Is there anything else I should try before diving into the gearbox?

L.A.B. · Jan 20, 2026

NickZ said:
it feels like shifter isn’t catching anything and there is only spring resistance moving lever fully up or down.

Classic case of the ratchet spring not being set correctly.

mdt-son · Jan 20, 2026

G

Thread 'gearbox ratchet pawl spring'

Apr 1, 2023

What happens when the legs of the dogleg spring are too far from the pawl ?

The problem I'm having is that randomly the bike will not shift into second. I move the lever and nothing happens. Fiddling around with it will eventually get it to shift and then it works fine.

Checking the space between the spring and the pawl I have ~0.055", quite a bit more than 0.010-0.015. Do you think that resetting the clearance will solve the problem or should I keep looking ?

Thanks
Greg

- Knut

NickZ · Jan 21, 2026

Thanks for this valuable input.
I installed a new ratchet spring during the rebuild, and thought I had it installed properly. But now I will go in and adjust it more precisely.

NickZ · 2026-02-04T12:01:14-0700

To follow up on this:

Yes, as suggested, the problem was the ratchet spring fitting.
After removing the GB outer cover, I measured a total of approximately 0.016" gap between the spring leg and the pawl. Meaning 0.008" between each edge of the pawl and each leg of the spring. It appears this was too much gap.

To adjust it, I bent the ratchet spring such that with the outer cover in normal use position, ratchet plate rotates freely with pawl touching lower leg of spring and there is a minimum of 0.010” of clearance between pawl and upper leg of spring. I say “minimum” because the ID of the spring coil is slightly larger than the OD of the ratchet plate peg it installs on. This allows the spring to move laterally a slight amount, resulting in slightly different gap size depending on where the spring ends up in relation to the pawl. This variance in gap size I measured is approximately 0.002”.

It now shifts normally up and down thru the gears.

concours · 2026-02-04T13:48:30-0700

NickZ said:
To follow up on this:

Yes, as suggested, the problem was the ratchet spring fitting.
After removing the GB outer cover, I measured a total of approximately 0.016" gap between the spring leg and the pawl. Meaning 0.008" between each edge of the pawl and each leg of the spring. It appears this was too much gap.

To adjust it, I bent the ratchet spring such that with the outer cover in normal use position, ratchet plate rotates freely with pawl touching lower leg of spring and there is a minimum of 0.010” of clearance between pawl and upper leg of spring. I say “minimum” because the ID of the spring coil is slightly larger than the OD of the ratchet plate peg it installs on. This allows the spring to move laterally a slight amount, resulting in slightly different gap size depending on where the spring ends up in relation to the pawl. This variance in gap size I measured is approximately 0.002”.

It now shifts normally up and down thru the gears.

Thank you for closing the loop. Others can benefit from this thread in the future.

marshg246 · 2026-02-04T14:12:19-0700

NickZ said:
To follow up on this:

Yes, as suggested, the problem was the ratchet spring fitting.
After removing the GB outer cover, I measured a total of approximately 0.016" gap between the spring leg and the pawl. Meaning 0.008" between each edge of the pawl and each leg of the spring. It appears this was too much gap.

To adjust it, I bent the ratchet spring such that with the outer cover in normal use position, ratchet plate rotates freely with pawl touching lower leg of spring and there is a minimum of 0.010” of clearance between pawl and upper leg of spring. I say “minimum” because the ID of the spring coil is slightly larger than the OD of the ratchet plate peg it installs on. This allows the spring to move laterally a slight amount, resulting in slightly different gap size depending on where the spring ends up in relation to the pawl. This variance in gap size I measured is approximately 0.002”.

It now shifts normally up and down thru the gears.

The proof is in the pudding. However, next time make the gap the smallest you can without either side touching.

Shifting 1st to 2nd not working right

NickZ

NickZ

L.A.B.

Moderator

mdt-son

Thread 'gearbox ratchet pawl spring'

NickZ

NickZ

concours

marshg246

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