G15 poor running still driving me mad

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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Location: HERTS UK

G15 poor running still driving me mad

Postby StuartN » Mon May 09, 2005 10:38 am

I am slowly getting to grips with my new G15. For those that have followed the previous correspondence this is what I have done:
A new battery has made starting easier. The old one was not holding a charge properly.
The bike wet sumps. I have relapped the pump carefully but it still collects too much oil after running and standing. I will either resort to straight 50 oil or have the timing case modified by Norvil as per Commandos. Anyway I am not concerned about this at the moment it is the poor running that is driving me mad.
I have checked out the carbs. They were perfectly clean and the bike doesn't have dodgy pipes or a rusty tank.
I have checked the ignition system out. It is running with a Lucas Rita not Boyer as I stated previously. I have not yet timed it as I suspect the demon is elsewhere.
The bike now starts easily, ticks over cleanly and runs well but it won't run over 65mph. At 55 it starts to get a bit troubled. I initially thought it was fuel starvation but I can't find a cause. Running otherwise is fine so I doubt ignition.
Has anyone met this before. I know I'm missing something but what!

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G15 poor running still driving me mad

Postby lawrence » Mon May 09, 2005 9:14 pm

I don't know anything about the Lucas Rita but on the Boyer if you have a poor connection in the ignition circuit ANYWHERE it acts as a rev limiter. Boyer told me there are 17 connections in the ignition circuit on my Bonnie so there is plenty of scope for checking [:(]

Lawrence [}:)]

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G15 poor running still driving me mad

Postby TommoT » Mon May 09, 2005 10:14 pm

Just a quick one: if the exhaust system is new, check that its not restricted somewhere. I have heard about pipes being blocked, silencers completely silenced, etc.. If some kind of blockage exists it will have exactly the effect you describe, and in addition it will run a little hot on the exhaust side.

Lets hear what you find out, when you do, if you do, etc.!


Ride Your Motorcycle As If Your Life Depended On It - Cos' It Does!

Posts: 15
Joined: Thu Apr 28, 2005 12:00 am
Location: HERTS UK

G15 poor running still driving me mad

Postby StuartN » Tue May 10, 2005 8:50 am

I've fixed it but I don't know how as I went through everything again before starting up. I checked the carbs again to find one slide sticking but I don't see how that would have caused it. I refilled petrol tank but the fuel was not old previously. I also checked the high tension leads but couldn't find anything amiss. Anyway bike now runs sweetly and I shall try to rack up some miles.

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G15 poor running still driving me mad

Postby itma » Tue May 10, 2005 5:59 pm

iffy suppressor caps come to mind as worth investigating perhaps?

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