Some (possibly demented) musings on a G3/LS

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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Pharisee
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Some (possibly demented) musings on a G3/LS

Post by Pharisee »

Please bear with me on this one, guys. It may get a bit involved.
As mentioned in previous postings on this forum, I recently acquired an abandoned restoration project... nominally a 1954 G3/LS. It had been completely dismantled and some other parts collected over a period of about 30 years.
I ought to state at this point that I'm not intending to do a 100 point restoration. I just want to end up with an aesthetically pleasing and ridable bike.
I've been in touch with the AMOC dating officer and it seems that the numbers on the frame, 350cc crankcase and the Burman gearbox are all from the same G3/LS which left the factory on 7th September 1954. I appear to have the components of a 'Matching Numbers' machine.
OK... so far, so good. Some of the parts of the 350 engine, however, haven't coped too well with being stored in a garage for 30 years... in particular, the cylinder barrel and the crankshaft. I think the barrel may well be past saving and the crankshaft will need a new drive side axle at the very least. There are parts missing... in particular, the short E3N dynamo.
Now... to my musings... Amongst the other bits I collected was a good condition complete, fully assembled bottom end of a 1960 AJS M18, including crankcase, crankshaft, connecting rod, camshafts, timing cover, points plate and the complete aluminium primary drive case with alternator and clutch. There is also the AMC gearbox that went with it.
Still with me?.... OK!
I would like, if possible, to keep the frame and 350cc crankcases together in the finished bike as they match.

Can I drop the later alternator type crankshaft into the 350 cases and then use the aluminium primary drive case with the alternator?

Image

Image
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Mick D
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Re: Some (possibly demented) musings on a G3/LS

Post by Mick D »

Hi

If it were me I'd try to keep it original, would be a shame to have a 'matching numbers' bike and then not have the complimentary chain case and electrics.
That barrel looks recoverable if it's a standard bore as does the crank with the exception of the timing side shaft, (and that could be re-ground and a modified bush used).

Edited to add:

I think you'll find the earlier crank case has a collar to locate the inner PCC, the later engine does not have this.

Regards Mick
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Re: Some (possibly demented) musings on a G3/LS

Post by Mick D »

Hi

Couldn't attach a photo to the edit above

This is a 1961 crank case:
LH Main Bearing.png
Regards Mick
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alanengineer
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Re: Some (possibly demented) musings on a G3/LS

Post by alanengineer »

Dont be put of by a bit of rust. A good wire brushing, rebore and coat of paint and your on your way.
I would keep a 54 bike looking like a 54 bike, take some short cuts (new switches etc) but i wouldnt do major mods without giving it a great deal of thought
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Re: Some (possibly demented) musings on a G3/LS

Post by clive »

You would be better to either recover the 350 barrel and fit a new axle or fit all the 1960 stuff including the gearbox and primary chaincase and have a mongrel. Trying to fit the later crankshaft in the earlier cases is just going to give you a whole load of trouble and will not make the bike a "matching numbers" one anyway as anyone worried about such things would know it had later parts. The 1960 crank will also be balanced for a 500 piston so building it as a 350 would not make sense to me. The axle for your 350 should be available and the 350 barrels if you needed a new one turn up at the jumbles on eBay etc. There are probably a few on many member's shelves so you could try a wanted ad. Personally I would go for the later engine gearbox and alternator, built as a 500 if you have the registration document already. You could always build up the 350 engine and have it to sell with the bike as the original stuff, or simply keep the crankcases and gearbox with it when it's time to sell it on.
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Re: Some (possibly demented) musings on a G3/LS

Post by alanengineer »

if you want the later type engine and alternator bits on a bike, why not swap your 54 for a later project
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Re: Some (possibly demented) musings on a G3/LS

Post by Pharisee »

They were just some idle thoughts I had whilst supping my third beer :) :beer:

Things have moved on apace. I've sourced another 350cc crankshaft that is in considerably better nick than the one I have (and less than the price of a new drive side axle). From the photographs, it looks like it has good axles (but I'll see better when it arrives.) It also has the timing pinion fitted and I needed one of those as the one I have is cracked from the corner of the keyway to the adjacent tooth root (Is that a common problem?)

The 350cc barrel has been attacked with a wire brush on an angle grinder and is probably recoverable. (I'll have to find something else to use as a mud-weight!). I took it over to T & L Engineering earlier today and they were quite optimistic. It's still the original bore and has never been re-bored so there's a bit to play with. I'll wait to hear from them in due course.

I've been looking at the two gearboxes I have. The later AMC box is working.... at least, the input and output shafts rotate and feel smooth.
The Burman box needs looking at. I can't turn either the clutch shaft or the final drive sprocket (by hand). I'm hoping it's just 'stuck' through lack of use and that there's nothing seriously wrong with it.

I've also been thinking about the clutch. I have very few parts for the Burman clutch and the bits I have are way past their prime. I do, however have a complete AMC clutch in good condition. I was browsing the archive yesterday and came across a brief article on using an AMC clutch with a Burman gearbox. It appears that a 3/8" wide spacer is all that's needed. If I can get the Burman box working, I may well use the AMC clutch as per the article. I have to keep the cost down to a level that SWMBO deems acceptable.

More musings in due course... probably. :lol:
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Re: Some (possibly demented) musings on a G3/LS

Post by Mick D »

Hi

The drive side axle looks fine, I'm sure it will clean up with Scotchbright, there's no need for it to have a superfine finish as it rotates via a ball bearing, secure the shaft to the bearing with one of the less aggressive Loctites.

Regards Mick
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Re: Some (possibly demented) musings on a G3/LS

Post by Pharisee »

Mick D wrote:Hi

The drive side axle looks fine, I'm sure it will clean up with Scotchbright, there's no need for it to have a superfine finish as it rotates via a ball bearing, secure the shaft to the bearing with one of the less aggressive Loctites.

Regards Mick
It really isn't fine... The thread on the end has rusted away almost completely and the splines for the shock absorber are very badly worn and corroded. It would need a bit more than a wipe over with Scotchbrite and a dollop of Loctite!
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Re: Some (possibly demented) musings on a G3/LS

Post by alanengineer »

Is it within your abilities to split the crankshaft assy ,get new bits, fit them and straighten all the bits up on assembly. If not , its worth getting a quote now as everything else you do revolve around this bit
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