G2 Clutch hub rebuild or alternative assembly?

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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G2 Clutch hub rebuild or alternative assembly?

Postby BigJock » Tue Aug 15, 2017 3:27 pm

1961 G2 Clutch basket assembly centre in knacked.
The bearing/rollers are complete and showing little wear but a helluva lot of play when all assembled. All the play is in the centre both outer and inner of the bearing.
Has anyone successfully rebuilt one of these or come up with an alternative? as obviously other than the rollers no parts are avail.

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Re: G2 Clutch hub rebuild or alternative assembly?

Postby Rob Harknett » Tue Aug 15, 2017 5:05 pm

The play you refer may be quite normal on the clutch.

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Re: G2 Clutch hub rebuild or alternative assembly?

Postby Ozmadman » Tue Aug 15, 2017 5:58 pm

Thought you could still get a clutch centre? Bit expensive though I seem to remember. You need to be sure you get the correct one as there are two different main shafts, the original and a modded one which is dependant on the age of the gearbox. Also, make sure it has the G2 clutch (determined by the amount of plates and whether any have a single sided frictions surface or not.) Also, as virtually all the gearboxes are interchangeable between the 350 and 250 there is a possibility you may have a 350 clutch and gearbox fitted and again two different main shafts with two different clutch centres. The gearbox numbers won't be any guarantee either as internal parts are generally interchangeable too. I have a spare G2 250 box which had a 350 main shafts in it.
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed

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Re: G2 Clutch hub rebuild or alternative assembly?

Postby BigJock » Tue Aug 15, 2017 6:20 pm

Gee - that makes me feel much better now! LOL.
So question now is how do I know what I have? Are there measurements for makeshift Tec?

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Re: G2 Clutch hub rebuild or alternative assembly?

Postby Ozmadman » Tue Aug 15, 2017 6:45 pm

Go here and look at page 55. http://archives.jampot.dk/book/Workshop ... models.pdf This will give you all the main shafts measurements then check what clutch you have by looking in the owners manuals here.
http://archives.jampot.dk/book/ Be aware that the workshop manual above is for all models so just make sure you are on the right section if you need to check anything else out.
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed

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Re: G2 Clutch hub rebuild or alternative assembly?

Postby BigJock » Tue Aug 15, 2017 7:24 pm

Thanks for the info. If I use the roller cage as a starting point - the outer circumferance is 1mm smaller then the basket housing and the inner is 0.7smaller than the iner hub. The rollers themselves should be 1/4 (6.35mm) mine are 6.25 - but without knowing the tolerances it dont mean much.
The output shaft is 18.4mm and the clutch is 7 plates total with 2 x steel outers and 3 friction all in good nick.

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Re: G2 Clutch hub rebuild or alternative assembly?

Postby g5 butch » Fri Aug 18, 2017 2:18 pm

Hi, What I did was mic the bore of the basket and the outside diameter of the hub and then calculator the clerance, the rollers are 1/4 x 1/4 and

then used oversize rollers, you can get •001" or •002". Remember that •001" oversize roller is •002" on diameter.

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Re: G2 Clutch hub rebuild or alternative assembly?

Postby BigJock » Wed Aug 23, 2017 2:30 pm

Good idea for the rollers - where did you get the oversizeds ones?
However - main problem is - if you imagine the clutch assy inner & outer face doen on bench with rear retaining place facing upwards - ok? Lift of the plate and you now have 3 different heights this plate must deal with - the inner hub the the roller cage sits on - the outer hub that then sits on the inner and the rollers themselves.
Thats whats happened here - all 3 are different heights due to crap design and wear. This appears to be the original hub and never been dissassembled either as all punch markings were still in position.
So - being a genious I took this along to my machinist after having to fing a piece of plate to machine then buying him tooltips - great so far. 4 days later - he screwed the whole damn thing up including the oem retaining plate!
So now totally screwed.

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Re: G2 Clutch hub rebuild or alternative assembly?

Postby Ozmadman » Wed Aug 23, 2017 5:06 pm

I think you are over thinking the whole thing, as Rob mentioned earlier, some play is normal and the clutch does wobble a little bit. That was certainly the case with mine but assembled it and put it back as it was and it has been fine with no problems.
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed

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Re: G2 Clutch hub rebuild or alternative assembly?

Postby SPRIDDLER » Wed Aug 23, 2017 5:32 pm

Ozmadman wrote:I think you are over thinking the whole thing, as Rob mentioned earlier, some play is normal and the clutch does wobble a little bit.

Agreed.
I'm not especially familiar with the Lightweight clutch with the cush inserts but in the H/W clutch the clutch rollers only roll when the clutch is free (disengaged). At all other times the whole assembly is turning due to the springs clamping the mainshaft, hub, plates and basket tightly together as one unit.
What if the Hokey-Cokey is what it's all about?

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