Problems selecting first gear.

[Storkfoot]

I have had more taken off the gear selector and the Layshaft taken down by 1.0mm. I have also swapped the second gear out for an old Italian 42 cog, 109.5mm diameter. I am still unsure whether the second gear I had in there was Indian, or not. All the gears spin freely on the layshaft.

The only other thing I noted was the gear cluster bearing track. I had replaced this when I built the engine but not knocked it in fully it seems. It stood 1.4mm proud of the casing. It is now 0.2mm proud. I suspect that this wasn’t the reason for struggling to get it into first gear but it may well have been the whirring noise I had.

All this is guesswork at the moment as I now need to put it all back together and try again.

Wish me luck.



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[dickie]

Good luck.

We all admire your perseverance.

[Storkfoot]

Good luck.

We all admire your perseverance.

Thanks. If I’d have known what part to buy to fix it, I’d probably just have done that. But, I’d had two gearboxes, two layshafts and tried two gear selectors and still not really found the problem.

[Storkfoot]

I put it all back together and went for a quick spin. It was a joy to be able to engage first gear effortlessly. Hopefully, this will continue.

What have I learnt by all this:

Absolutely need to check that, as Sticky’s says, the first gear cog stands proud of the Layshaft by at least 10mm.

Absolutely need to check that the gear selector prongs do not stand proud of first gear.

Not to trust any of the remade layshafts and gear selectors. If I was building this engine again, I’d take the gearbox to a dealer and build the Layshaft up on the premises.

As regards buying gearboxes, try and buy old ones that you know the history of. If you are buying new gearboxes, tread carefully with Indian made ones.

If you are changing the gear selector track, make sure you knock it in properly

Come the Winter, I’ll have a look at the condition of the Layshaft (the marks around second gear concern me) and the gear selector.

[ULC Soulagent]

Well done that man for sticking with it

[Storkfoot]

Update:

This is still performing as it should, thankfully

But, I have a similar issue on the Stage 4 200 engine I have built for my Series 2. The engagement of first gear, whilst not as bad as the SX150 engine I resolved by getting the layshaft and gear selector machined, is a bit hit and miss.

This Stage 4 200 is a Jet 200 engine. I am using the original gearbox, original endplate, original layshaft. The new gear selector sliding dog is FA Italia. I suspect the sliding dog is the problem again.

I hope that I can resolve this issue, the same way I did before. By getting the sliding dog machined down to ensure it does not interfere with the gear shim when putting the engine into first gear.

I did take the opportunity to speak with a dealer who sells the FA Italia and SIL sliding dogs. They build engines themselves and had not encountered issues with the FA Italia ones. They did agree that the Indian SIL ones can be rough and ready meaning that the bearings do not roll easily along the path of the sliding dog. I asked this as I did toy with the idea of buying one of their SIL ones but I recall that, several years ago, I tried a SIL sliding dog which made it almost impossibly hard to change gear.

My question is, is it possible to get a small Dremel bit into a SIL sliding dog and, even if it is, will it work to smooth the bearing path on hardened metal. Has anyone successfully, or unsuccessfully, tried this please?

[Storkfoot]

A friend has pointed me in the direction of what to use to smooth out SIL sliding dogs.

However, at this point, I am, once again, going down the route of getting the FA Italia (that is what is stamped on this one) sliding dog having 0.8mm shaved off the prongs.

When I took the gearbox and Layshaft out of this engine, this is what I found on the underside of the gearbox shim - a groove which has been made by the sliding dog prongs when I have been trying to select first gear. This was a new shim about 100 miles ago.



Given that, in this case, the Layshaft and gearbox were original Jet 200 from the same engine, the conclusion must be that the Italian factory making these sliding dogs is making them incorrectly.