I have a question about "Gear box shim 2.3, MRB" Having recently fitted a shim, the clearance is now 0.35 mm....still outside the recommended limit of 0.3 mm. What are the consequences of riding with this excessive clearance?

In Stickies manual, he says that the first gear needs to be a little proud of the flat surface of the lay sgaft. Is it possible to ask a precision to grind this ahsft surface down until this is achieved or would there be dire results.

Thanks John

Question

I have a question about "Gear box shim 2.3, MRB" Having recently fitted a shim, the clearance is now 0.35 mm....still outside the recommended limit of 0.3 mm. What are the consequences of riding with this excessive clearance?

In Stickies manual, he says that the first gear needs to be a little proud of the flat surface of the lay sgaft. Is it possible to ask a precision to grind this ahsft surface down until this is achieved or would there be dire results. 

Thanks John

Accepted Answer

Loose gears will eventually damage the selector and may jump out of gear, you could also have kickstart problems.

The layshaft has to be lower than the 1st gear or it will not shim up, this can be done by hand with a hand grinder, or with a bench grinder or correctly on a real grinder, it only needs to be say 0.10 - 0.20mm below.

Lambretta Gear box shim 2.3mm, MB