Trouble Shifting Into First

Yes I have exact same issue, cannot engage 1st unless shifting down from 2nd while still moving. This started following gear box rebuild, new selector spring I suspect is not to tolerance of original. Bike is off road currently so am looking to fix this for next summer. Be very interested to see how you get on with your selector prb. Cheers.

Did anyone find a definitive cure for this? My 71 750 Roadster has exact same symptoms... Tried new clutch pack - Sureflex - still same result. Adjusted clutch with both 1/4 turn and full turn of free play at adjuster end, same result. Clutch operation seems perfect from all other perspectives. If you slip into first from neutral it does not engage - sometimes with ratchety sound like spinning cog has a pawl rubbing on teeth - if you try a second time immediately it does engage with no noise. No problems with any other gear and no problems with second down to first on move. Lay shaft bearing has been replaced by a knowledgable person... I would have thought someone may have found cure by now?

Cheers
Richard

I had exactly this problem about a year ago, the box was originally good then I noticed it becoming more difficult to select Ist from neutral until it became almost impossible this happened over a couple of rides maybe 100 miles. Stripped the gearbox and noticed the following: both bearings were loose in the case, the gearbox oil was a bit low, one of the sliding bushes in the gear (can't remember which one) was very tight. I replaced the layshaft roller with one of Mick Hemmings ball races, loctited in both bearings, new bushes, one of the second gears had bad wear so replaced that, put the old selector spring back in as the new one didn't fit properly, put it all back together with one pint of fresh 80-90 with a dab of Nulon additive and the box has selected perfectly over a couple of thousand miles. So take your pick, I obviously did something right but I don't know exactly what (although I did talk to Mick Hemmings on the phone and he ascribed the symptoms as resulting from the loose layshaft bearing.)

Check your primary chain tension. I have found on a lot of bikes that have shifting problems, the primary chain is way too tight. Follow the manual, there needs to be some slack in the chain, and the primary can be pulled tight by the rear chain if the gearbox is not tightened in place properly.

Your "Problem" may be no problem at all. AussieCombat hit the nail on the head. When the gearbox and the clutch have broken in and have miles on them they will disengage completely. My '72 does the same thing and it is freshly broken in. I shift into neutral and let the clutch engage with no pressure from the lever at any stop that I judge is going to be longer than 30 seconds, when it is time to get going I rev the engine, clutch engaged, quickly disengage the clutch and pull up smartly on the gear lever, it never fails to go into 1st. Sometimes I put a small bit of pressure on the gear lever while SLOWLY releasing the lever, snicks right in.

You can test this by stopping on a flat surface with 1st gear engaged and engine running. Can you easily roll your running motorcycle forward and backward with almost no effort? If so there is nothing wrong with your clutch or gearbox, if all the other gears engage as you stated.

If your primary chain is too tight and your gearbox bushing(s) are worn you will have a similar issue, but you will feel resistance when doing the rolling test.

Bill.

ludwig said:

jsouthard said:

..I have a difficult time shifting into 1st gear from neutral..

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Can you be more specific ?
Is it :
1 . I actuate the gear lever , but nothing happens = selector fork does not move .
2 . Selector fork moves the gear , but the 4 dogs do not engage = rattling noise .

In other words : Is it a selector problem , or do the gears refuse to engage ?

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Hi Ludwig,
I can't speak for the OP, but i have similar symptoms and would welcome feedback as I'm about to strip the box to investigate, but am not confident of fixing it . Here's a brief description of mine.
I bought the bike last year, and when hot, it struggled going into first at standstill. The lever moves, but the gear doesn't quite slip in. There is no rattling noises etc. If i deliberately drag the clutch, it'll slip in.
When i stripped the bike, i found the primary belt was way too tight. So assumed this may have been the cause.
I stripped the gearbox. I believe it had not been stripped before. Bike had 20k miles and box internals all looked in great condition.
However, the shell was cracked (between the bearings). So Norman White got a new shell and assembled the box for me.
I rebuilt it with slightly more slack than should be in the primary belt.
So with all of the above, i was disappointed to find it still has the same problem!
I hope the selector is fouling on the inner case, if its not that, I'm gonna struggle...

I've loosened off the primary which as specified in the workshop manual at around 10-15mm free play.

I've refreshed gearbox with Redline Heavy Shockproof Gear Oil.

The box is less problematic but still has underlying issue.

Have tried Roadscolar suggestion - in 1st gear at standstill with clutch in I can freely manoeuvre bike with no obvious rolling resistance, and all other gears engage OK.

The layshaft bearing is still fairly new, about 1000 miles ago, so will see if it settles down with time.

Thanks for suggestions - interesting how many people have similar issue and no clear fix over such a long time.

Cheers

Still think it's a layshaft shimming issue. My Commando gearbox is absolutely perfect (the best gearbox on a motorcycle I have ever experienced) and I think that it is mostly due to dumb luck shimming it after a rebuild and replacement of the layshaft bearing. I had a Matchless G12 with identical gearbox that had exactly the symptoms you describe. With that bike, I am convinced that I put too many shims in which resulted in too little layshaft endlpay when I rebuilt the bike. I was doing it strictly by feel as I did not have a dial gauge to check it precisely. My guess is that if you reduce the shims somewhat and increase the endplay, your problem will go away.

tpeever said:

Still think it's a layshaft shimming issue. My Commando gearbox is absolutely perfect (the best gearbox on a motorcycle I have ever experienced) and I think that it is mostly due to dumb luck shimming it after a rebuild and replacement of the layshaft bearing. I had a Matchless G12 with identical gearbox that had exactly the symptoms you describe. With that bike, I am convinced that I put too many shims in which resulted in too little layshaft endlpay when I rebuilt the bike. I was doing it strictly by feel as I did not have a dial gauge to check it precisely. My guess is that if you reduce the shims somewhat and increase the endplay, your problem will go away.

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Interesting. My gut feel is that if it is anything to do with endfloat, then its cos there is too much! Will have to wait till I've had a look, which sadly won't be for a couple of weeks cos I'm off to India. Really looking forward to a dose of Deli Belly...!