Starting procedure and getting a new bike running

Information relating to the Matchless G9 or AJS Model 20 500cc twin
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Starting procedure and getting a new bike running

Postby rob4586 » Sun Mar 12, 2017 8:28 pm

Good evening gents,

I've just bought a 1951 Matchess G9. I believe it ran about 6 months ago, so my plan to get her running is:

1) Drain the old petrol and replace with new petrol
2) Drain the oil out the sump and put it back in the oil tank
3) Fix the advance/retard mechanism as this is currently jammed solid - I'm not sure why this has happened?
4) Cleans the carb

Then I need to know how to start the bike, so would someone please advise? I can't even seem to find a decompression valve on the bike? Where is this usually?

Regards,
Rob

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Re: Starting procedure and getting a new bike running

Postby Groily » Sun Mar 12, 2017 9:57 pm

6 months isn't that long luckily.
Sounds as if the camring has jammed in the housing at the cb side of the magneto through damp/corrosion/disuse, or the cable has seized. You'll need to fettle and lubricate to see exactly what has happened, but it shouldn't be too hard.
Definitely put the oil back in the tank, yes, as it might all be down below after its hibernation. Also check the primary chaincase oil level. If most of the engine oil has gone south, some of it may well have passed the drive side main bearing and filled the chaincase. You don't want that, as the clutch will slip, so reduce the chaincase level until it just touches the lower run of the chain.
The fuel might still be OK, but can't hurt to change it. Carb might have got a bit sticky depending on what was in the tank, so worth cleaning the thing, paying particular attention to the needle valve on the float chamber inlet, and the main jet and pilot jet as they can get gummed up. But probably OK. Fuel taps may leak to start with, and the banjo on the bottom of the main bit if the carb may also leak, if the original type 76 carb with separate float chamber is on there. Less likely if it's a Monobloc. Some people reckon petrol only lasts for a few weeks these days, but I've never had that problem personally.
There isn't a decompression lever or valve lifter. Fuel on, (air slide closed if fitted), tickle it well, a little bit of retard at the handlebar lever, and a prod on the k/s - should be all it takes to fire her up as they are easy starters usually.
If there's an anti-wet-sumping tap fitted in the oil supply line, it needs to be ON! Might need to think about the spark plugs and contact breaker points if the beast won't go after a few kicks, but if it went before, it should go again without too much trouble. Fingers crossed.

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Re: Starting procedure and getting a new bike running

Postby Duncan » Sun Mar 12, 2017 10:07 pm

3) Fix the advance/retard mechanism as this is currently jammed solid - I'm not sure why this has happened?


I find that the "wine glass" cable end connecter can sometimes jump out allowing the cam ring to become wedged, a couple of strong magnets on either side can sometimes be enough to pull it out/free.

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Re: Starting procedure and getting a new bike running

Postby rob4586 » Sun Mar 12, 2017 10:09 pm

Groily wrote:6 months isn't that long luckily.
Sounds as if the camring has jammed in the housing at the cb side of the magneto through damp/corrosion/disuse, or the cable has seized. You'll need to fettle and lubricate to see exactly what has happened, but it shouldn't be too hard.
Definitely put the oil back in the tank, yes, as it might all be down below after its hibernation. Also check the primary chaincase oil level. If most of the engine oil has gone south, some of it may well have passed the drive side main bearing and filled the chaincase. You don't want that, as the clutch will slip, so reduce the chaincase level until it just touches the lower run of the chain.
The fuel might still be OK, but can't hurt to change it. Carb might have got a bit sticky depending on what was in the tank, so worth cleaning the thing, paying particular attention to the needle valve on the float chamber inlet, and the main jet and pilot jet as they can get gummed up. But probably OK. Fuel taps may leak to start with, and the banjo on the bottom of the main bit if the carb may also leak, if the original type 76 carb with separate float chamber is on there. Less likely if it's a Monobloc. Some people reckon petrol only lasts for a few weeks these days, but I've never had that problem personally.
There isn't a decompression lever or valve lifter. Fuel on, (air slide closed if fitted), tickle it well, a little bit of retard at the handlebar lever, and a prod on the k/s - should be all it takes to fire her up as they are easy starters usually.
If there's an anti-wet-sumping tap fitted in the oil supply line, it needs to be ON! Might need to think about the spark plugs and contact breaker points if the beast won't go after a few kicks, but if it went before, it should go again without too much trouble. Fingers crossed.


Groily,

Thank you for your response - it's a great help!

I had the cam ring out tonight and it's jamming, but not apparently obvious. When I tighten the union that the cable goes through into the mag it jams solid....back it off a when turns and it's okay. I will have to do some most investigation on this to try and figure out what is going on. The cable is running nicely and the cam ring itself is rotating fairly freely.

Fuel smells a bit "off" so I will just change it for good measure. The carb fitted is an Amal 626, which I'm guessing is a later addition? I believe these are quite a reliable carb from when I've had them on my BSA bikes though. Am I correct in thinking there is no requirement to have a charged battery when starting the bike as the magneto will generate the spark irrespective of the battery? Also, I'm guessing the headlight switch is just for lights? There is no ignition switch as such?

Sorry for the school boy questions! This is new to me.

Regards,
Rob

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Re: Starting procedure and getting a new bike running

Postby rob4586 » Sun Mar 12, 2017 10:11 pm

Duncan wrote:
3) Fix the advance/retard mechanism as this is currently jammed solid - I'm not sure why this has happened?


I find that the "wine glass" cable end connecter can sometimes jump out allowing the cam ring to become wedged, a couple of strong magnets on either side can sometimes be enough to pull it out/free.


This is what I found this evening, Duncan. The wine glass had popped out and jammed into where the spring is located in the union. I'm not sure how it managed to pop out? Is this fairly normal?

Cheers,
Rob

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Re: Starting procedure and getting a new bike running

Postby Duncan » Sun Mar 12, 2017 11:54 pm

Is this fairly normal?

I would say not normal, but it does happen, I am not sure if it is an issue with replacement/pattern parts.

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Re: Starting procedure and getting a new bike running

Postby Groily » Mon Mar 13, 2017 7:30 am

Could be wear on the tip of the wine glass plunger, and yes it happens now and then.
New plungers are available if wear there is the prob. Unlikely to be a problem with the camring itself luckily, as long as it is fitted so that the plunger's notch doesn't move so far 'up' or 'down' that it causes the plunger to slip out of engagement. That can be the case sometimes and can be a bit of a pain, as you don't have many options: the ring needs to be in the correct place, and its range of movement should be controlled by the little pin that goes in the wider notch at the bottom.
You can't just fit the ring wherever you fancy, as the mag's internal timing demands that it be where the maker's put it, subject to a small amount of fine tuning achieved by adjusting the position of said pin - which is an eccentric on a small screw that goes through the end-housing, locked in place by a little expander thing that hides the screw head.)
No need for battery or any of that, and yes the switch just does the lights. No ignition switch unless someone has fitted a switch to the earthing 'button' (or wire take-off if you have a later bit there) on the magneto end cap.
626 Concentric is commonly fitted as they're cheap and cheerful. Pilot circuit is the most vulnerable thing there, as it can gum up. But if correctly jetted and with a suitable slide in it, should work fine.

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Re: Starting procedure and getting a new bike running

Postby 1608 » Mon Mar 13, 2017 7:36 pm

Just an obvious, but very important point:- if you are not familiar with the 'wet sumping' issue, make sure that if a tap is fitted to the oil feed it is in the on position.

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Re: Starting procedure and getting a new bike running

Postby dave16mct » Mon Mar 13, 2017 10:49 pm

Why not pop down to the North West Section clubnight on the first wednesday of the month? One of our members has a very nice 1951 G9 and you can't beat a bit of first hand advice!
Dave.

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Re: Starting procedure and getting a new bike running

Postby rob4586 » Wed Mar 15, 2017 9:45 pm

Good evening gents. I now had her running and enjoyed my first ride...and I didn't break down!

I've managed to correct the cam ring issues buy adjusting the amount of travel available using the adjuster on the cable. I have, however managed to do something so it is only running on one cylinder...probably knock the timing at the points - I can soon sort this.

Other issues identified are:

1) Battery is completely dry, so replacement is on order.
2) Throttle cable is frayed, so a replacement has been ordered
3) None of the lights work, but I am unsure whether this is to do with the U/S battery leaving an open circuit?

Where is the clubnight held? I'd love to but usually I'm working in Lincolnshire during the week....maybe there is a club over this way though?

Cheers,
Rob

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