Ignition timing

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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ChrisTheChippy
Member
Posts: 274
Joined: Wed Feb 07, 2018 12:02 am
Location: Essex

Ignition timing

Post by ChrisTheChippy »

Hi all
At last found a couple of hours to fettle the matchless. Last time I posted I was on the point of trying to get it started then we had a week away and haven't been able to do anything since.
This afternoon I removed and cleaned/ checked carburettor seemed all in good order and was already surprisingly clean which raises my suspicions that someone has been attempting to start bike before and has already gone for the obvious and cleaned carburettor .
So I thought I would fit a dummy tank chuck some fuel in and give it a go after a quick clean of the points . I have already checked for sparks .
Result ? Nothing, not a squeak not a chuff chuff not even a backfire .
Next step check ignition timing .New points fitted points gap spot on . Set piston to 1/4 BTDC firing stroke advance bobweights and the points where already open when they should be just about to open . When I checked the backplate it was already turned to full adjustment with no further movement being available which means the auto advance bobweights will have to be moved to get them back in the correct position .
The amount of error probably equates to about 3/8 " of piston travel which means I have plenty of spark's but not necessarily in the right order 😀.
My question for the forum is should I have expected to see at least some sign of life even with ignition timing that far out and do you think it is worth while checking the valve timing while I am in that area ? Surely the guy couldn't have got that wrong ? Only 2 cams and they are marked ? Opinions invited.
I have searched the spares department and note that they have the correct auto advance removal bolt in stock . Seems a tad expensive though . Not a criticism merely a comment . I will have to order one along with the new center stand spring I need . All this means more time especially when I just want to get on with it now .
All the best
Chris
Mick D
Posts: 2886
Joined: Mon Mar 24, 2014 5:44 pm
Location: Aberdeenshire

Re: Ignition timing

Post by Mick D »

Hi

You don't actually need the specific extractor bolt, you can use the retaining bolt and a length of steel rod to extract the auto advance / cam - measure the depth of the hole and cut a length of rod, (plain portion of a drill for example), to that length minus half of the retaining bolt thread length.

Re-set the cam position and try again would be my advice.

Regards Mick
ChrisTheChippy
Member
Posts: 274
Joined: Wed Feb 07, 2018 12:02 am
Location: Essex

Re: Ignition timing

Post by ChrisTheChippy »

Thanks Mick
Good tip . Think I will try that.
Done a little bit of research and seems that ignition timing needs to be pretty near the mark for the G2 .
Cheers Chris
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