lambretta rear hub nut massive mystery.

[paulnobodyimportant]

Putting my original series 2 li engine back into my scooter. But first I stripped it down including taking out the layshaft. Put it all back together and then went for the usual M16, but it didn't fit. Confused measured diameter of series 2 layshaft and it was 18mm. Measured 3 other layshaft ends and diam/thread was 16mm, which is what it should be.
Can anyone throw any light onto the difference, cos it's keeping me awake. Aaagj

[Rich_T]

I would say that someone bashed the rear axle with the hammer and although the threads are not mushroomed the pitch may well have been damaged. Either that you you have got a mullered hub nut. Suggest you find out which by checking with a thread gauge then running a die down the axle, you'll be there forever with a thread file. If it is just the nut you have got away lucky.

[rosscla]

I screwed a thread file trying to get new stainless nuts from at least three different suppliers on mine. None would go more than half a turn on. Ended up putting the old nut back on which went on by hand all the way. Will replace lay shaft next time it's in bits.


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[paulnobodyimportant]

I know what you mean Rich, but have a look at the photo below, the diamater and threads look consistent, ie no mushrooming. But do you think that its some supreme being saying I need to replace it as the splines are buggered. Although in practise, they don't look as bad as the photo shows

[Minority]

Some weird Indian variant? (Just a guess)

[wack 63]

Looks like the thread part has been welded on to me plus its undercut where it meets the splines. I'd bin it to be safe.

[Grumpy225]

Looks like the thread part has been welded on to me plus its undercut where it meets the splines. I'd bin it to be safe.

I thought that at first also. I assume the rest of the axle matches the one on the right?

Either way, that thing is junk. Put it on the wall of shame.

[Yanker]

I picked an 18mm one up at the parts fair at Mersea a couple of years back: dimensionally correct in all areas but the nut thread - never noticed that until later. It is in OK nick on the bearing surfaces. Will have a close look for evidence of weld - but why do that? Thought maybe Lambro layshaft? Now know why it was only a fiver, you live and learn

[paulnobodyimportant]

Just looked at mine and no weld. Scooter Restoration have seen the same photo and they are at a loss. They confirmed that's it's not a lambro or any other variation. Now I could get a M18 nut, but no locking washer would fit, unless I got one fabricated. b@11@x.

[dirtyhandslopez]

'Kin L.