Speedo drive mashed

Information relating to the Matchless G9 or AJS Model 20 500cc twin
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Re: Speedo drive mashed

Postby clive » Fri Mar 08, 2019 12:14 am

Oggers wrote:Mick - excellent photo - Many thanks...

The plot thickens - Upon disassembly I found no thin washer or the "cup" for the hub rubber oil seal. Excellent photographic procedure in the archives which shows these items should be present - as does the manual. Not sure about the implications of them not being there, and whether they contributed to the catastrophic failure, but clearly it would seem they should be present.

Persoanlly I am leaning towards a loose locking ring on the hub as root cause. Also found the wheel spindle nut (on the nearside) was not paticularly tight. :o


If the cup and thin washer was missing the whole wheel would lock up if the spindle was tightened. I expect it was being held on by the chain and rear brake stay. Had this with a rigid I purchased many years ago where the spacers wee round the wrong way and so pushed on the outer of one of the wheel bearings. Only found out after I had ridden it 20 miles home.
clive
if it ain't broke don't fix

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Re: Speedo drive mashed

Postby Mick D » Fri Mar 08, 2019 7:59 am

clive wrote:If the cup and thin washer was missing the whole wheel would lock up if the spindle was tightened


Hi

I'm not convinced that's correct - all the cup and thin washer do is to locate the grease seal, the wheel bearing adjuster would bear directly on the bearing outer and continue to function as designed and the bearing inner clamp up to the spindle is unchanged.
I'll stick with my diagnosis - the drive seized and wheel rotation caused the adjuster to unscrew and wreck the drive case.

This of course does not condone leaving out the cup and washer which would result in loss of grease from the wheel bearing as seen on the hub cover in the first photo.

Regards Mick

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Re: Speedo drive mashed

Postby Oggers » Fri Mar 08, 2019 10:57 am

Mick - Yes. I like your theory too. Cannot really say for sure if the drive was goosed, will revert. Main pinion looks fine though, not sure about the worm. My theory may be invalid due to the nature of the thread on the adjuster ring, and the wheel did not lock up, but who knows.....

Progress - I have managed to source an indentical speedo drive from fleabay - which saves on reaming, and I believe the others from AMOC spares etc are of a different thickness. Other bits from AMOC will follow.

So - next question. Reassembly. Basically as per pics and photo - all excellent, many thanks. Note "seal cup" orientation tick, note seal tick, I believe adjuster ring winds fully into the hub, then back off half a turn, then lock up the lock ring - tight - with loctite perhaps. Anything else I should be aware of?

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Re: Speedo drive mashed

Postby Mick D » Fri Mar 08, 2019 11:42 am

Hi Oggers

I wouldn't use Loctite on the lock ring and especially not before I had ridden the bike for a while and then re-checked the bearing adjustment / play.

I'm sure you already know that you have to tighten the wheel spindle fully before you can tighten the nut that retains the speedo drive - one not to forget ;)

Regards Mick

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Re: Speedo drive mashed

Postby Oggers » Tue Mar 12, 2019 7:40 pm

Gents

One (hopefully) final Q if I may, and pardon my ignorance. What is the purpose of the adjusting ring, and how do i adjust it? I assume to engage the dogs on the drive corrrectly?

Profuse thanks

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Re: Speedo drive mashed

Postby clive » Tue Mar 12, 2019 9:10 pm

the adjusting ring is for the clearance in the bearings. To engage the speedo drive correctly you simply ensure the drive "dogs" are lined up with the cutouts in the adjusting ring before you push it home. If they don't line up simply turn the speedo til they do then rotate it to the right position once engaged.
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Re: Speedo drive mashed

Postby Oggers » Wed Mar 13, 2019 8:55 am

the adjusting ring is for the clearance in the bearings.


Understood. So how far is the adjusting ring screwed into the hub? All the way? or am I missing something?

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Re: Speedo drive mashed

Postby Mick D » Wed Mar 13, 2019 9:30 am

Hi Oggers

Firstly make sure the circlip is correctly fitted to the other side of the hub - if this has become dislodged you won't be able to adjust the bearings.

Once you have assembled the bearing spacer seal etc. screw the adjuster in until it comes to a stop, it will have contacted the shaped washer which is bearing on the bearing outer. Wind the adjuster back out by 1/2 a turn and lock it in position with the lock ring, (the one that takes a C spanner).

R Brg.png


Once the wheel is refitted you should feel barely perceptible play at the rim - go for a ride and re-check the play afterwards and adjust back to barely perceptible if necessary.

Regards Mick
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Re: Speedo drive mashed

Postby Oggers » Wed Mar 13, 2019 11:22 am

Mick

Just the job....Many thanks...again.....

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