1955 G80S No Auto Advance Unit

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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1955 G80S No Auto Advance Unit

Postby branstonbiker55 » Sat Oct 07, 2017 5:53 pm

Joined the Club a couple of months ago and bought a 1955 G80S today, had bad kickback when starting so thought I would check the timing, the timing cover has the bulge, but there is no auto advance unit and no manual control either. What has happened? The Magneto is marked Model: 9R1 Type: MK11A 10 54 Serial No 42293A. Any advice appreciated.

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Re: 1955 G80S No Auto Advance Unit

Postby SPRIDDLER » Sun Oct 08, 2017 5:59 am

Welcome, Ben.
Are you reading the model number correctly? For your bike it should be SR1, not 9R1.
The 10 54 dates yours as manufactured Oct 1954.
As you realise it should have an auto A/R assembly inside the bulge.

Just a guess but if it really is a 9R1 perhaps it's a mag for a stationary engine :?
What if the Hokey-Cokey is what it's all about?

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Re: 1955 G80S No Auto Advance Unit

Postby 1608 » Sun Oct 08, 2017 6:38 am

It is possible to do without the a/r unit and simply set the timing to the desired amount of advance for normal running. It just makes starting difficult as you have already found out. The a/r unit may have been removed if it was faulty and the p/o didn't fancy lashing out for a replacement.

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Re: 1955 G80S No Auto Advance Unit

Postby branstonbiker55 » Sun Oct 08, 2017 6:47 am

Thanks for your reply, you are quite right it looks like a 9 but actually it is an SR1 Mag, appears to be right model but just no auto advance, can't find new ones on internet, but found complete mag same model on e-bay with auto unit, no bids @ £50, but collect only from Tonbridge which is miles away. Have messaged to see if will post. Assume I can swop the bits over to add the auto unit then have a spare mag. I am now walking with a limp from the kickback and will be trying to go cycling this morning! Ben

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Re: 1955 G80S No Auto Advance Unit

Postby Reynard24 » Sun Oct 08, 2017 7:36 am

It might be worth giving Tony Cooper a ring, he's in the West Midlands and sells new A/R units for the K series mags as fitted to Velocettes so may also sell one for the SR1.

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Re: 1955 G80S No Auto Advance Unit

Postby Rob Harknett » Sun Oct 08, 2017 10:31 am

The A/R units do come up for sale on e bay. The advance for normal running would need to be fully advanced. The timing is with the A/R set fully advance, or lever set at fully advanced if manual. With only a fully advanced setting, the bike would kick back making starting very difficult. It would need warming up to normal running temp. before setting off, or it will keep stalling etc. when you shut down.

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Re: 1955 G80S No Auto Advance Unit

Postby branstonbiker55 » Sun Oct 08, 2017 2:26 pm

Thanks everyone for your assistance, I was desperate to go out for a ride on it, but I think I will try to get an A/R unit and set the timing first.

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Re: 1955 G80S No Auto Advance Unit

Postby bitza » Sun Oct 08, 2017 3:36 pm

Try Tony Cooper Halesowen West Midlands. 110 Olive lane, Halseowen, West Midlands, B 62 8 LT
Phone. 0121 559 2405
Did my mag first class job and knows his stuff.

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Re: 1955 G80S No Auto Advance Unit

Postby GOLDSTAR » Mon Oct 09, 2017 6:59 am

just a 'heads up' there is or was a help section in the club identifying club members. location and assistance offered, dunno if this still runs but my thoughts are should you obtain the part from the Tonbridge vendor and he is reluctant to post it, I'm sure a local member would do so for you, a thought.
kind regards

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Re: 1955 G80S No Auto Advance Unit

Postby Eamonn » Mon Oct 09, 2017 7:12 am

GOLDSTAR wrote:just a 'heads up' there is or was a help section in the club identifying club members. location and assistance offered, ...


It's called the "Assistance List" and can be found under the Club menu heading on the http://www.jampot.com page.

Details on how to update the list can be found at : http://www.jampot.com/forum/viewtopic.php?f=45&t=17461

Corners like a Lego man

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