Gearbox / layshaft shimming issue.

[corrado]

I've got a close ratio gearbox that when assembled correctly on a layshaft sits below the top of the layshaft. Hence I'm unable to shim it. I've got a selection of layshafts, Casa, FA Italia, MB, Sil, all with the same issue (a pacemaker gearbox works fine with all of them though). I've also got a couple of unknown branded layshafts that line up ok with the c/r gearbox but I'm a bit reluctant to use them in a tuned engine. Looking in Stickey's 3rd edition he mentions grinding down part of the layshaft close to where the oil seal goes. Page 81. I can't get my head around how this might help, as even if it allows the layshaft to be pulled through the bearing further it'll just take the gears with it I presume? It would seem more logical to turn down the top of the layshaft slight so that the gears sit higher but that would be too easy so I'm not seeing the obvious error of going that route. Anybody have any constructive comments to add?

[ULC Soulagent]

have you tried flipping the loose gears the other way round maybe

[ULC Soulagent]

The grinding of the layshaft on page 81 refers too the middle pic and not the bottom pic with the o-ring seal.

[HxPaul]

It would seem more logical to turn down the top of the layshaft slightly so that the gears sit higher

+1

[corrado]

The grinding of the layshaft on page 81 refers too the middle pic and not the bottom pic with the o-ring seal.

Doh, it makes sense now, I only saw one pen.

[ULC Soulagent]

Hope u get it sorted

[dscscotty]

what make/manufacturer of the gearbox?

[corrado]

what make/manufacturer of the gearbox?

It came via Italy but presumed Indian. SX200 1st, 2nd, 3rd with Li 150 4th. Same ratios as one made by DRT but no markings on it.
1/49 - 2/40 - 3/37 - 4/34 + 12-14-17-20
I was planning on trying it in place of my Li150.

[hullygully]

think Broady & Cyclone do a shim that goes inbetween the loose gears & rear hub brg
soz it goes between the layshaft & brg derrrrrrrrrrrrr

[gp200ts1]

A shim between the layshaft and bearing won’t help as it will not change the layshaft to gears clearance. You would need a shim that sits under the gears between them and the shaft.

[gaz_powell]

AF do a shim for under the loose gears and the bearing

[Tony Hart]

Resurrecting an old thread as I’ve got the same issue. Does anyone know if anyone makes a shim that sits under the loose gears on the layshaft? I’ve tried a couple of layshafts and they all stand 0.37mm proud of the stacked loose gears. The gearbox is an LI150 but I believe Indian made. It’s in very good condition so would like to use it rather than sourcing another.

[Storkfoot]

In answer to your question, no I don’t. I have had to get a couple of layshafts machined down so that first gear sits proud of the layshaft.

Then you also have the issue of the gear selectors standing proud of first gear and pushing on the gear shim

[Tony Hart]

In answer to your question, no I don’t. I have had to get a couple of layshafts machined down so that first gear sits proud of the layshaft.

Then you also have the issue of the gear selectors standing proud of first gear and pushing on the gear shim

Never easy is it