Valve timing cams

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
Dreverl1
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Joined: Sun Mar 11, 2018 7:54 pm
Location: BRIDGEND UK

Re: Valve timing cams

Post by Dreverl1 »

[quote=Has it ever run right for your friend or has he always had the backfiring problem? If it hasn't, then Duncan's comment about a cam from an early Matchless engine (i.e. with the mag at the rear of the cylinder) may be a clue/relevant.

To be honest, I cant really answer that. This is the first old bike hes had and it was only after I rode it that I said that wasnt right. Maybe it has been flogged...

Now that I have the timing side apart (mostly) I think it might be an idea to remove the question by putting a correct exhaust cam in as it is different to the inlet. The exhaust has a line on the front and when I took it off, the dot was on the back face (and only one dot in total on that face). The inlet cam has all sorts of numbers on it (which I wrote down but dont have on me) but the exhaust doesnt have anything...

Too many questions???
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ajscomboman
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Location: HAMPSHIRE UK

Re: Valve timing cams

Post by ajscomboman »

dreverl wrote:
The club also runs a mag exchange service.

http://www.amoc-parts.com/store/comersu ... tegory=122
Yeah, we are going to see what they have.

We can put a reconditioned mag on and move onto the issues, one by one.

Cheers[/quote]

I maybe wrong but I think that exchange mags and dynamos are only available to club members.
Dreverl1
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Re: Valve timing cams

Post by Dreverl1 »

Hi,

I'm not a member (of this club, almost every other one ;-)) but the owner of the bike is so should be OK I think.

Cheers
Andrew
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ajscomboman
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Re: Valve timing cams

Post by ajscomboman »

dreverl wrote:Hi,

I'm not a member (of this club, almost every other one ;-)) but the owner of the bike is so should be OK I think.

Cheers
Andrew
If that's the case then yes I'd have thought so. I do however know that there is very little in the way of exchange units at the moment so wouldn't leave it too long.
Dreverl1
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Location: BRIDGEND UK

Re: Valve timing cams

Post by Dreverl1 »

Hi All,

I think Id like to try and get a different exhaust cam as there is a question about if we have the right one. Can anyone tell me if a 1946 cam is correct for this 1954 engine? I was looking at getting this one to at least see if the lobe is in the right place.

https://www.ebay.co.uk/itm/Ajs-M16-Cams ... OSwCMtaZxV~

Cheers
Andy51
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Re: Valve timing cams

Post by Andy51 »

For '54 on, you need a higher lift cam cam marked with an 'H' on the front of the cam lobe. A pre '54 low lift cam will work, however, but you will lose a little bit of performance. In my experience good 'H' cams are few and far between on the autojumble circuit, but I have seen plenty of earlier ones. Most are pitted on the flanks and nose, you may have to look at a lot to find a good pair. Cheers, Andy
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