G5 - First Serious Ride

Information relating to the Matchless G5 or AJS Model 8 350cc Lightweight
User avatar
Ozmadman
Posts: 2651
Joined: Wed Dec 14, 2011 1:02 am
Location: ESSEX UK

Re: G5 - First Serious Ride

Post by Ozmadman »

Yes the front pipe is a push fit into the head and a leak there could cause a problem. I used some Firegum on the pipe as I pushed it home and then wiped off anything that had squeezed out and now no leaks. There should also be a small dog leg shaped bracket just under the front pipe on the straight run which attaches it to the frame underneath the engine, this is the only support for the front pipe there is.
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
starfield181
Posts: 114
Joined: Wed Aug 18, 2010 11:56 am
Location: WILTSHIRE UK

Re: G5 - First Serious Ride

Post by starfield181 »

The wet Easter weekend had one benefit, plenty of time to tinker with the bikes and the G5 has finally come to the top of the queue for some attention. Today I set the ign timing in meticulous detail and I would bet serious money that it is now absolutely spot on. Though to be honest I think it was probably right anyway as back plate seems to be pretty much where it was when I started. I removed the complete exhaust systems and reseated the pipe fully into the head with some sealer to make sure it was airtight. Again there was no obvious sign of slackness or leaking but now I know its right. Finally I replaced the coil with a brand new one from my spares stock.

Bike started easily enough and sounded a bit rich yet with some spitting back through the carb when cold (it does not currently have a choke mechanism fitted, I just give it a good tickle to get started). Took it for a run and it went well enough with none of the hunting I have had in the past but I still have popping and banging in the exhaust on the overrun. Back home whilst still hot, I was able to set up a fairly slow reliable if slightly lumpy tickover. If you flick the throttle it will still pop in the silencer sometimes as it slows down. However, there no longer any evidence of the black smoke (richness) I used to get. This went away when sorted out the blocked pilot jet and was able to open the air adjustment screw from fully closed. Plug is an NGK 7ES by the way.

So bike is now as good as I can get it. None of the things I thought it might be have proven correct so far. Not sure what to try next other than a carb swap if I can find a suitable one on another bike or in the 'stores'. I suppose it could be valves needing attention but given the condition of the rest of the bike and engine I am inclined to think (hope) not and will leave this till last.

Galling thing is I dug out my MAC Velo and took it for a 50 mile ride yesterday with no more attention than a tyre pressure check and some fresh fuel. Went like a dream.Think the G5 is telling me something but I am not giving up yet.

PeterF
Locked