Author Topic: Removing the worm drive locknut  (Read 369 times)

Offline Rudgeman

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Removing the worm drive locknut
« on: 28.05. 2019 13:02 »
Hi again - in my quest to replace the non-standard inner timing cover on my '61 Super Rocket with the tacho drive version, I've decided to remove the oil pump just to see how things are. Seems rude not to whilst I'm in the vicinity.

No problems I can't sort out with the pump - but discovered that the crank pinion has about 2mm axial play which looks really odd. A bit of research tells me there should be a washer in there between the oil worm drive and the pinion. There isn't.

Simple enough to fix, you'd think, but how on earth do I remove that lock nut ? I've bent the washer out straight again - and yes, I know it's a left hand thread, but it won't budge. I'm in danger of buggering up the nut in my efforts so thought I'd seek advice before going on to more drastic solutions.

I've tried locking the shaft using the narrow hex on the worm drive - but it's too narrow for a decent spanner and laughed at my home made narrow spanner.

Next I tried locking the rear wheel and putting it in 4th. I can get a lot of torque on it that way but eventually the clutch slips and the nut doesn't.

I didn't really want to get into the primary chaincase - but maybe that's what I'll have to do. At least, if I do, the fact that it's a left hand thread should mean I don't undo the cush drive nut - unless that's LH thread too ! I don't think so, at least it shouldn't be.

Any ideas would be very welcome.

R

Online berger

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Re: Removing the worm drive locknut
« Reply #1 on: 28.05. 2019 13:14 »
might have been lock-tighted and will need heat to break the stuff. I once put goo on the mainshaft clutch nut and forgot i'd goooood it.  I had a 2ft bar on it and when I got it off the goo was like sort of powdery. what a pillock I am *problem* *bash*

Offline Rudgeman

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Re: Removing the worm drive locknut
« Reply #2 on: 28.05. 2019 14:52 »
Good idea Berger - I'll give it a shot.
R

Offline Swarfcut

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Re: Removing the worm drive locknut
« Reply #3 on: 28.05. 2019 15:30 »
Try a close fitting 25/32AF socket, well supported, and a strategic smack on the drive bar. The shock should undo it, in gear, brake on, but avoid any sideways force on the crank. Otherwise weaken the nut with careful cuts and sacrifice it. They are not usually troublesome, so try Berg's warm up trick first before resorting to true violence.

Swarfy.

Offline kiwipom

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Re: Removing the worm drive locknut
« Reply #4 on: 28.05. 2019 23:23 »
hi Rudgeman, if i were you i would get the rattle gun on it , it will come off no problem, good luck, cheers 
A10.G.Flash(cafe racer)Honda 250 vtr. Yamaha Virago XV920.

War! what is it good for?Absolutely nothing, Edwin Star.
NewZealand

Online Greybeard

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Re: Removing the worm drive locknut
« Reply #5 on: 29.05. 2019 09:43 »
The flats are shallow. Grinding the lead-in off the socket may be a good idea so you get the best possible contact.

Offline Rudgeman

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Re: Removing the worm drive locknut
« Reply #6 on: 02.06. 2019 13:58 »
Hi - thanks for all your good ideas. It's finally off, but I had to remove the primary chaincase to provide a reliable reaction. It turns out that as well as omitting the washer twixt worm drive and crank pinion, the previous person to work on this had re-used the old tab washer. The tab washer had no tab to locate to the crank so the worm and lock nut where simply tightened against each other, and very tight at that.

Just as well I took a look in the chaincase though. I've discovered a newish clutch made by
Lyford Classic Services. I haven't heard of this supplier, are these clutches any good ?

It's got two spring nuts nearly undone and the opposite two screwed in about as far as they can. No wonder it was dragging. I can't believe anyone, even the person who fitted the worm drive, would have left it like this. Is it possible these nuts can undo in normal service ?

Fun and games,
                             R

Online berger

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Re: Removing the worm drive locknut
« Reply #7 on: 02.06. 2019 14:57 »
Rudgeman Lyford classics is a geezer and his wife[can't remember names] that I met a few years ago at his house in Nottingham. they used to deal in BSA parts and had a web page. he built a twin engined BSA monster years ago[think there's a photo on web] and took it apart as it was very heavy. very nice chap but I think he's stopped trading as I tried to contact him a couple of years ago and no reply *beer*

Offline a101960

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Re: Removing the worm drive locknut
« Reply #8 on: 02.06. 2019 15:46 »
Quote
I think he's stopped trading as I tried to contact him a couple of years ago and no reply
Yes, long since stopped trading.

Offline Swarfcut

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Re: Removing the worm drive locknut
« Reply #9 on: 02.06. 2019 16:25 »
The clutch nuts have little to hold them still, but a good dose of Loctite should do the job. Try to get the clutch to work, it should do a reasonable job. There is almost a hierarchy  of BSA Clutches and no doubt other Forum Members will chip in with their experiences, and you will get some idea of the best way to proceed if this clutch proves less than you expect.

 Swarfy.