G15 mk 2 primary chaincase

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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Re: G15 mk 2 primary chaincase

Postby ajscomboman » Mon Jul 20, 2020 2:08 pm

All of a sudden I don't feel quite so bad.

Peter you get the motor out and give me an easy step by step way as it's usually a complete swine to work on these monsters.

Fired it up again and there is a knock and then silence. No amount of revving can get it to repeat itself, been round the thing with a screwdriver to the ear and nothing can be heard that's untoward around the bottom end. When someone blips the throttle and I'm listening no knocking is heard. The end of the alternator when listening with the screwdriver sounds nasty though. That's the only area that does. I'll whip the outer cover off tomorrow now I've finished the decorating and see what I find. If nothing then I fear I maybe joining Mr Gibson! :headbang:

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Re: G15 mk 2 primary chaincase

Postby raffles » Mon Jul 20, 2020 5:37 pm

Rob you could try taking five thou off the rotor, it only needs to touch the stator now and again to make the noise you
hear somtimes and as we all know there is always some movement at certain rpm
Tony

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Re: G15 mk 2 primary chaincase

Postby ajscomboman » Mon Jul 20, 2020 5:40 pm

raffles wrote:Rob you could try taking five thou off the rotor, it only needs to touch the stator now and again to make the noise you
hear somtimes and as we all know there is always some movement at certain rpm
Tony


I'm hoping that will be the case. Tomorrow I'll be biting the bullet.

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Re: G15 mk 2 primary chaincase

Postby g80csp11 » Mon Jul 20, 2020 6:38 pm

G15CSR strip.jpg


Rob , see who fixes theirs first !
most repairs should be possible at the side of the road !, that's why I carry so many spanners
no faults detected yet !
- Phazon static timing Ok at 32 deg BTDC
- Cam timing marks OK ( 6 chain links between marks)

check cam lift and inlet / exhaust valve opening and closing tomorrow, then have a think
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Re: G15 mk 2 primary chaincase

Postby ajscomboman » Mon Jul 20, 2020 7:20 pm

Peter you are way ahead of me and have the distinct advantage due to the fact that you don't have to pull the complete exhaust system to get to anything.

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Re: G15 mk 2 primary chaincase

Postby ajscomboman » Tue Jul 21, 2020 5:14 pm

Well Peter I caught you up and maybe overtook you. The pipe came off along with the cover and as I suspected the rotor was loose on the shaft. The primary chain too tight and to cap it all off barrel base nuts slightly loose. Every nut and bolt has been gone through and harmony has been restored. It revs and runs sweet now and the vibes have all but disappeared to a proper level for a G15. No leaks from the base or anywhere else. Just got to take the pipe off again and put the outer chaincase cover back on and off for another test on Sat hopefully. :beer:

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Re: G15 mk 2 primary chaincase

Postby clive » Tue Jul 21, 2020 5:43 pm

Things are getting better. 15 mile run and only issue oil on the rear tyre as i over filled the oiltank and it was chucked out the breather! When retightening the steering as it needed just a tad further adjustment i found the bottom rubber of the rear suspension will allow it to slide completely off. In fact it did so as i was twisting the frame about to get the front off the ground. Same can happen the other side with only a slight pull when there is no weight on the rear. Am i missing a washer/spacer or is it just a dodgy Girling type replacement.? The top fits between the frame but the bottom has nothing to stop it pulling off. I realise that when on the move there should be no sideways pressure but it does seem odd that itss an easy sliding fit. Thoughts?
clive
if it ain't broke don't fix

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Re: G15 mk 2 primary chaincase

Postby g80csp11 » Tue Jul 21, 2020 5:53 pm

Ok , you might have found your problem well done .
who put you engine together ?
Ive just confused things with somewhat reduced exh valve lift on the G15 than measured on the P11, and strange valve opening
dont actually know what it should be so might have to repeat

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Re: G15 mk 2 primary chaincase

Postby ajscomboman » Tue Jul 21, 2020 6:01 pm

g80csp11 wrote:Ok , you might have found your problem well done .
who put you engine together ?
Ive just confused things with somewhat reduced exh valve lift on the G15 than measured on the P11, and strange valve opening
dont actually know what it should be so might have to repeat


The previous owner. I don't think it was a poor job overall, in fact it's had a shed load of money spent on the rebuild. The bike has never been on the road after it was built so I'm the one doing the shakedown. Fortunately it's been a simple fix and all is now good in the world.

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Re: G15 mk 2 primary chaincase

Postby clive » Sun Jul 26, 2020 10:39 pm

Well I have finally been out and enjoyed myself. No problems this time, about 40 miles covered, only real issue a bit of popping on the over run but one of the silencers is held on by a substantial hoseclip. As I took a turn down my test track, I mean the M40, the heavens opened but fortunately it did not last long. Wet but happy on my return,
clive
if it ain't broke don't fix

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