Intermiitent gear change problem

[a101960]

Before I start buying parts, I thought I would ask for ideas and suggestions about an intermittent gearbox problem that I have. Most of the time it works fine, but occasionally when changing up from 1st to 2nd , 2nd does not engage. If I go back down to 1st  and reselect 2nd  it engages as it should, just occasionally this will happen a couple of times in succession, but mostly it once I have changed back to 1st and then reselected 2nd the problem does not reoccur. This is entirely a random and unpredictable event. I suspect maybe the selector plate “Claw” is worn or perhaps the timing is maybe slightly out. 3rd  and 4th  are not affected, and changing down from 2nd  to 1st seems to be unaffected. Selecting neutral is not a problem either.  Can anyone suggest what might be going on here?

[Butch (cb)]

Sounds like maybe you have Moto Guzzi internals fitted.

[chaterlea25]

Hi,
A dodgy return spring could also be a cause 

John

[coater87]

 

 When it happens do you hear second gear trying to engage or is it more like second gear just disappeared?

 Lee

[a101960]

When it happens do you hear second gear trying to engage or is it more like second gear just disappeared?

By way of explanation, I have rear set foot rests so the pedal action is reversed. As I lift the pedal upwards from 1st it feels as though nothing is happening, and it does feel as though 2nd gear is there at the end of the pedal travel, but it won't "go in" it's a bit difficult to describe. When I go back to 1st and try again 2nd engages immediately with a nice positive action.

[muskrat]

When you said "claw" I think your talking a plunger box. A worn or chipped claw will affect all up shift or all down shifts. (I've had that problem compounded by a too thick inner cover gasket))
I would try the return springs first.
But it sounds very similar to a problem I had with my plunger box. turned out to be a worn/slightly bent selector fork. Found it by swapping them over and found the problem moved from 1-2 to 3-4.
Cheers