1970 S gearchange

Hi.
A problem that i cannot abke to dolve.
I have rebuilt a lot of gearbox transmissions that work all great.
Also this S transmission have always worked well but now the lever, with the bike running, doesnt shift because looses the engagement.
If you stop the bike it work again, all gears engaged.
If you turn the gearlever bolt with a spanner all the gears engaged.
Changed ratchet, the two springs, pawl, etc.
I will change the brass of the ratchet shaft.
What happens?
Thanks.
Piero

Make sure your primary chain is not too tight. And the dogleg spring is correct.

Check the first gear bushing, I have had issues with worn ones in the past, jumping out of first mostly.

John in Texas

H

N0rt0nelectr@ said:

Check the first gear bushing, I have had issues with worn ones in the past, jumping out of first mostly.

John in Texas

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Hi.
The gears dont junping out.
Only that the lever go up snd down righr but doesnt engage.
Piero

Dogleg spring is top suspect for moving lever not giving a gear change.

kommando said:

Dogleg spring is top suspect for moving lever not giving a gear change.

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+1 – I know this is an old chestnut, but it still amazes me that you can put a gearbox together perfectly well, but have a useless gear lever if that spring isn't just so! The last time I had my gearbox apart I installed a brand new spring direct from AN, out of an excess of caution – did it work? Did it f***! I had a go at getting it right, but ended up just putting the old spring back in. Bingo!

Hi Piero

I had a similar problem a few years ago. I double and triple checked everything but I could not make it change gears correctly.

Finally, I removed the outer cover again, and with the ratchet plate in the cover I simply moved the lever up and down to see if the pawl moved the ratchet plate properly. It did not.
I noticed that, after moving the plate from neutral to first gear position, the pawl would then drag on the plate as the lever returned to its central position.
This moved the plate back a little bit, although the box remained in first gear (when fully assembled).
When the lever was moved again to try to select 2nd gear, the pawl missed the tooth on the ratchet plate because it was out of position (very slightly).
So the box remained in 1st gear.

The way I resolved this was by grinding some metal from the concave face of the pawl which was dragging the plate. It now changes gears perfectly.

However, I later thought that maybe there could be something else causing the pawl to drag the plate, possibly a worn bush.

Maybe I attacked the symptom and not the cause.

You mentioned that you will change the brass of the ratchet shaft. That may be bush I was thinking of. It may work.

Hope this helps.

kommando said:

Dogleg spring is top suspect for moving lever not giving a gear change.

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I agree, look at the hairpin spring it could be weak and make sure the dog leg is towards the bottom.
John in Texas

I was thinking about your problem and I remembered that I had a similar problem. It turned out that the pawl carrier was ever so slightly rubbing up against the spring retainer (I call it a bridge). Just had to grind off a very small amount of material on the open section of the bridge and it worked as advertised.
John in Texas

kommando said:

Dogleg spring is top suspect for moving lever not giving a gear change.

Click to expand...

Hi.
Dogleg means hairpin spring?
Thanks.
Piero

Yes