1958 Matchless G3

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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Re: 1958 Matchless G3

Postby George Kaplan » Wed Jan 09, 2019 8:57 pm

Second question (actually its sort of two questions)

The front bracket has a hole through it. However it is roughly 3/8" at one end and roughly 1/2" at the other. Is this correct? I can't imagine why it needs to be of two different bores?

If it is correct then my question is what is the stud like that goes here to attach the engine plates?

If not the I assume it should be 3/8" all the way through?

Here are a couple of pictures.

Front Bracket 2.jpg


Front Bracket 3.jpg


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Re: 1958 Matchless G3

Postby Duncan » Wed Jan 09, 2019 9:41 pm

This file should give you all you ever wanted to know about engine mounting studs and spacers for post war singles: http://archives.jampot.dk/technical/General_technical_topics/Singles_engine_mounts_studs_spacers_1946-1964.pdf

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Re: 1958 Matchless G3

Postby George Kaplan » Wed Jan 09, 2019 9:56 pm

Hi Duncan, thanks for that that is a very helpful file, I thought I had saved all of the relevant files from the archive but I must have missed that one.

It confirms what I thought, the hole should be the same all the way through for a 3/8" stud. I will undo the previous modification when I repair the other issues.

That just leave the other question regarding symmetry of the brackets around the centreline of the frame. My gut says that they probably are symmetrical but it would be nice if someone could confirm.

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Re: 1958 Matchless G3

Postby George Kaplan » Wed Jan 16, 2019 8:47 pm

I managed to get some correct engine plates which arrived today. I had hoped that once the plates were here then the alignment of the engine would be obvious and I was pleased to find out that it is obvious.

In the first picture the two highlighted mounting points have not been modified and confirm that the alternator models share the 3 1/2 inch width and I can now define the extent of the required repairs. Note I don't have any studs yet but plenty of bar in the correct diameters so I have cut slightly oversize lengths to use to locate everything and will turn them into studs when I repair the frame.

Image


The second picture shows what I had wondered about, if the engine mounts are symmetrical around the centre line of the frame? It isn't.

Image

When I was putting the engine plates on I have noticed that the front mount that has been sawn off hasn't been bored out as I had first thought. The engine mounts are 3/8" bore at the edge but are a bigger bore in between.

I have take a poor phone picture of one of the rear mounts of what I mean.

Image

Now I can get on with repairing the frame.

Once that is done I want to get it on its wheels and to do that I need a right hand fork leg. I have made some enquiries but haven't found one yet.

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Re: 1958 Matchless G3

Postby clive » Fri Jan 18, 2019 8:51 pm

My gut instinct was to say that the frame mounts were not symetrical but I was too lazy to go out and check in the dark sorry about that. With my Advertising Police hat on can I point out that we do not allow advertising in the general forum. There is a special section where it is allowed. Alternatively use the adverts which get published in the magazine and reach a much wider audience. (Clue here for those trying to sneak adverts past me, make your posts so long that i skip them!)
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Re: 1958 Matchless G3

Postby George Kaplan » Fri Jan 18, 2019 9:51 pm

Clive, please accept my apologies, I didn't mean to try to sneak in an advert in here. I do have an advert in the Wanted section already.

As it happens I received an email a couple of hours ago from someone who might have some of the parts that I need.

My comments were only meant to explain progress and comment on any immediate gaps that I need to fill in. In future I will be less specific and just say I need to fill in a gap or something.

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Re: 1958 Matchless G3

Postby clive » Fri Jan 18, 2019 11:57 pm

no problems John. But I was also hinting that such long posts might be passed over. If you are looking for advice on a particular issue it may be better to start a different thread asking for that specific information with a title making clear what you need to know. Then continue to use this thread for your progress reports which I am sure will be read by those less impatient than me!!!!!!! I am pleased that adverts are getting results for you. If you need to include photos to discuss the part you are after you can use the adverts section of the forum http://www.jampot.com/forum/viewforum.php?f=56
regards
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Re: 1958 Matchless G3

Postby clive » Sat Jan 19, 2019 11:16 am

Well now its light I have been out to check the frame on my bike (1950ish rigid G3L) and it definitely has offset brackets. The engine is mounted so that the centre rib of the crankcase sits fairly centrally to the frame (I think but did not measure). Looking again there is a scallop in the bottom of the crankcase and this definitely sits equidistant around the frame. The critical issue in truth is to get the front engine sprocket when mounted (with the correct spacer between it and the main bearing) to line up so the primary chain runs square to the clutch sprocket. I suspect the reason for the PO's liberal activity with the hacksaw was because at some time an ex-WD motor has been fitted. The rear mount for these is definitely narrower that with later crankcases and requires different spacers but I cannot remember if its similar with the front engine mounting and I had some spacers behind the plates when I had an ex WD motor in mine. A number were sold off and used to keep what was then just an old hack on the road. It looks like you have the cases in about the right place in your photo.
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Re: 1958 Matchless G3

Postby George Kaplan » Sat Jan 19, 2019 2:34 pm

Clive, thanks for the feedback on both your bike and the comments on WD cases. WD cases do make sense. WD cases have mounts 2.5 inches wide (I have a set of WD cases) whereas some time in mid 1948 (according to Roy Bacon) they changed the cases so that both the 350 & 500 bikes used the same ones. Those later 350 cases had mounts 3.5 inches wide.

Now that some late style engine plates have been acquired the position of the engine is obvious as it is determined exactly by where it mounts at the bottom front of the frame where it fits into a gap rather than across a tube (if you get what I mean). The gap at the front is an exact fit for the width of the engine case.

If the PO sawed them to fit the narrower cases its a pity he/she didn't cut them a bit straighter. However, I had a couple of hours this morning before I had to go out so I have now mounted the frame in my mill and squared up the previously wonky saw cuts. I hope to get some time today to make repair pieces and weld them in to return the frame back to stock.

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Re: 1958 Matchless G3

Postby George Kaplan » Sun Jan 20, 2019 9:10 pm

This weekend Mrs Kaplan has been out of action due to virus and chest infection so I was promoted to more important tasks than screwing around with old bikes. However I did manage some progress in between other duties.

I mounted the frame on my mill and squared off the ends of the cut mountings. As usual the actual cutting took about 1% of the total time to do the task. When that was done I put everything back together and measured the 4 repair sections that I had to make, made them and tacked them into place. Then I partly dismantled everything again and and welded them in place. On the rear brackets there is a small area there I cant get my TIG torch in but it wont be detrimental to the repair.

One thing I noticed when doing this was that the holes in the frame brackets are not central to the brackets. The repair pieces I made were turned on a lathe so the OD and ID are concentric. When offered up in their intended destinations and the ID's lined up, the OD's are slightly offset. Observing this I pondered if the holes in the frame mounts were drilled after the frame had been assembled. That way any manufacturing variances would not matter?

Anyway after welding the repairs I blended the two OD's with a flap wheel.

Image

Image



John

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