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GrandPaul
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gavin eisler
Total Likes: 1
Original Post (Thread Starter)
#815146 07/05/2020 3:05 PM
by Allan G
Allan G
Shifting the A65 into second from first and it over throws the gear into a false neutral between 2nd and 3rd.

The bike has rear sets so it’s gp shifting (1 up 3 down)

It doesn’t do this for any other gear or going back from 4th to first at any point.

In the past I’ve had the plunger gouge away at the cam plate, when this was replaced I rounded the point on the plunger and took 2 coils off the spring. It’s been fine for several thousand miles.

The bike has the 1971 style inner timing cover, and I have checked adjustment of the spring and cotton reel and all seems ok there.

Only thing I can think of is the pawl on the selector shaft might be getting worn or weak spring but I would have thought that would effect all gears and not just one. Same with the gear change return spring.

Sadly I can’t replicate the motion on the drive way and it selects second fine like that.

Any thoughts before I chuck another selector in?
Liked Replies
#815224 Jul 6th a 08:18 AM
by Phil in Germany
Phil in Germany
Hi Allan,

recently I have had an A65 on the bench with exactly the same over-shifting problem.

When shifting up from 1st gear you ended up in the false neutral between 2nd and 3rd. Engine and g/b were manufactured in 1971 as well.

Apparently, I have been the third guy trying to sort this issue.

Initially, I had also suspected an issue with the cam plate, In that case the culprit was something else.

In the end the issue was caused by a quadrant that was haphazardly manufactured right from the start.

There are two bosses on the inner side of the inner timing cover that limit the travel of quadrant when you shift up and down.The 'stop' on the quadrant was rather short and with some wear that took place over the years on the bosses themselves, the movement was too much.
The right one was assembled, the left one was the quadrant I took out of my spares stash.

[Linked Image from up.picr.de]

This is the situation with the ('new') quadrant loosely assembled in the inner timing cover in the shift up-position, quadrant on the boss...

[Linked Image from up.picr.de]

On that particular bike there was an additional issue. The layshaft was shimmed wrongly, as they did not start with the standard shim parts-# 42-3079 on the timing side. Anyone had chosen to put additional shims in there and to take a thin shim from a Triumph on the drive side end.
Surely, this did not help either as the sliding gears are too far to the left side before any shifting takes place.

After swapping the quadrant and shimming the layshaft correctly, the issue was resolved.

I hope this helps.

Cheers!

Ph.
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