G15 Mk 2 seat lug

Information relating to the Matchless G15 or AJS Model 33 750cc twin. This also includes the G15 Mk II and the G15/45
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G15 Mk 2 seat lug

Postby clive » Sat May 02, 2020 9:37 pm

I am trying to track down a seat lug stud for my G15 mk 2 as the thread seems to be dodgy on the present one. According to my parts list its 023520 and the nuts are 000292. The club does not stock the stud but does stock the nuts (in stainless) which are described as " nut half 5/8 for seat stud ". Norvil don't list either. Is it possible the stud listed by the club will do the job 000597, not sure of its dimensions? Not sure I would want a half nut though.
clive
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Re: G15 Mk 2 seat lug

Postby John Jarrett » Sun May 03, 2020 3:59 am

Clive,
I haven't got a G15 but I believe the arrangement is the same as a G12CSR or G80CS. From memory there are two half nuts on either side. The first to tighten the rear loop to the front frame and the second to tighten the seat bracket. You need the half nut as the seat bracket is designed to fit between the two half nuts.
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Re: G15 Mk 2 seat lug

Postby John Jarrett » Sun May 03, 2020 6:40 am

Clive,

It is one of those inaccessible areas that is difficult to see when all up together, but I should have checked before I posted the previous response.
The set up should be a full nut first for the rear loop and half nut for the seat bracket. The width of the stud for this set up on one of my bikes is 5 5/8" but is incredibly tight for the seat bracket nuts with some thread showing on the half nut on one end.

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Re: G15 Mk 2 seat lug

Postby clive » Sun May 03, 2020 11:00 am

Thanks for the reply John but I think it is different. The seat bracket will only fit either side of the frame. No room for nut. Only 000292 is listed in the parts list along with a washer. Mine has two thick ones but they go outside the seat bracket. The currentvstud is too long and may have been used with a sidecar mount.
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Re: G15 Mk 2 seat lug

Postby ajscomboman » Sun May 03, 2020 11:41 am

The stud is currently being made but until this virus issue eases there is no way we're going to get them for a while.

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Re: G15 Mk 2 seat lug

Postby mdt-son » Sun May 03, 2020 1:00 pm

clive wrote:I am trying to track down a seat lug stud for my G15 mk 2 as the thread seems to be dodgy on the present one. According to my parts list its 023520 and the nuts are 000292. The club does not stock the stud but does stock the nuts (in stainless) which are described as " nut half 5/8 for seat stud ". Norvil don't list either.


Hi Clive,
I was sursprised reading your statement, because I am adamant having seen this stud with Norvil. Sure enough, you have mixed up the numbers. The stud has p/n 023250 and is listed with Norvil (SS though and sold as an assembly w/nuts only).

For later year models w/coil ignition, I believe there was another stud providing the necessary length for a thick and a shallow nut, and a plate carrying an ignition lock.

-Knut

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Re: G15 Mk 2 seat lug

Postby Mick D » Sun May 03, 2020 1:35 pm

Hi

If you know the dimensions and thread get one made by ACME Stainless, nuts and washers too if you want, very good prices and quality.

https://acmestainless.co.uk/shop/studs/ ... cba1185463

Regards Mick

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Re: G15 Mk 2 seat lug

Postby dave16mct » Sun May 03, 2020 1:58 pm

Clive, you haven't said what length of stud you want. I have a new one here which is 5 7/8" x 5/8", with long thread at both ends and 2 new nuts. Also has the threaded hole for the earth screw on one end.
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Re: G15 Mk 2 seat lug

Postby Peter Morris » Sun May 03, 2020 2:26 pm

Sounds like the one Dave has is right Clive. If it's any help my G15CS stud is 5/8" x 5 - 6" long (difficult to measure on bike). It has a threaded hole in one end that is 1/4" all threads Cycle 26TPI. It has 2x half nuts at each end, and the seat lugs go either side of the rear frame lugs, not between the nuts.

I have no idea why it has 2x half nuts each end, I bought the bike already restored. The hole in one end is for the ignition switch bracket to bolt onto.

My '66 31CSR also has a 5/8" stud but is only 4 1/2" long... not sure it's correct though as the nuts don't go on fully.

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Re: G15 Mk 2 seat lug

Postby clive » Sun May 03, 2020 2:30 pm

Thanks dave i will check length when i next go on my health exercise to my garage. I will then PM you so i dont have to tell myself off!. :rofl:
clive
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