Matchless G3LS 1953 questions

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
Jonny Astro
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Matchless G3LS 1953 questions

Post by Jonny Astro »

Hi Everybody,

After much umming and arring I finally bought myself a G3LS. It's a 1953 model and has been fully restored - not a show winner, (I didn't want one of those), but very tidy and clearly well put together by someone who knows their stuff. All the obvious things have been done - recon mag, dynamo, rebuilt engine and gearbox, new rims, nice paint, etc. Beautiful Smiths Chronometric speedo! It starts really easily, which in my opinion is a good indicator.

When I collected it it had only done about 50 miles since the rebuild and I have put about another 50 on it since. It's really nice, and I look forward to many more miles.
A few questions have come to mind though - hoping people can advise:

1/ It has a small oil weep from the primary chain cover. (Apparently this is compulsory though...?) It has the T section seal fitted. I tested the band clamp screw and it was only finger tight - presume it has just bedded in since the rebuild. I put a couple of judicious turns on it, but how tight should I do the screw? I don't want to distort the cover.

2/ I need to play with the carb - tickover is a bit slow - If I'm riding it and I leave it for a few seconds the engine dies. But if I put it on the side stand it's OK for some reason. What's going on there? Do I need to play with the primary jet, or maybe the float height?

3/ Spark plus is an NGK BPR6ES. My searches suggest that a B7ES is the notional equivalent of the FE80 KLG original. Is the 6 a bit "hot"? Does the addition of the resistor give the magneto a hard time? I read that maybe the B7EV palladium type may be better from that point of view. Is this related to the ticker issue?

4/ The battery is holding up despite a few night rides using the headlamp, (6v / 25W...Eek! Good job I know the roads round here!), so it's clearly charging. But the ammeter never seems to get beyond the centre point. Is this just a quirk of the mechanical regulator? Or is the ammeter not calibrated properly?

5/ Anything else I should look for/be aware of?

Jon Bentley
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Harry44
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Re: Matchless G3LS 1953 questions

Post by Harry44 »

No. 2 On the assumption you have a monobloc carburettor, as the float chamber is offset to one side, putting the bike on the side stand alters the mixture ( its the same as changing the float height. Probably the bike was tuned while the bike was on the stand.

My 500 ticks over nicely when I'm sat on it and slowly dies down and stops on the sidestand. I use this as a magic trick for the local kids.
si is does non opportunus vos postulo a maior pango
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GOLDSTAR
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Re: Matchless G3LS 1953 questions

Post by GOLDSTAR »

would it be a monobloc in 1953? anyway your question relating to a resistor type spark plug, I think I am right in saying the concensus of opinion is they are not suitable for a magneto fired engine, the rest of your questions other than to say tighten the chaincase retaining nut/bolt/screw I could not answer, but enjoy your bike these old nails are addictive. kind regards
SPRIDDLER
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Re: Matchless G3LS 1953 questions

Post by SPRIDDLER »

Welcome Jon.

1. It's impossible to give you a definitive answer to this but I doubt that you would distort the chaincase unless you use unreasonable force. To ensure that the securing band is well seated around the chaincase halves tap the front of the band back towards the rear wheel before or as you tighten the bolt. If you're unsure about how much to tighten the bolt it may be best to tighten the bolt a few turns and and leave it to see if the leak has stopped. If not try a couple more turns but stop if the band lugs begin to distort or the gap between them has closed up. As a guide the ends of my chaincase band are tightened with a slot head screw and nut, (not a hex head bolt and nut) and I can tighten it sufficiently with just a screwdriver.
There are two open holes in the inner chaincase (Dynamo armature shaft and clutch mainshaft) and oil mist can pass out, run down the inner chaincase and drip.
There is also the crankcase breather (usually a short, say 2" or 3" long piece of copper pipe) located behind the inner chaincase at the drive side main bearing boss on the crankcase which breathes oil mist. It's not easy to see as you need to look up from under the chaincase, probably with a mirror unless the piece of pipe is long enough to protrude from behind the chaincase.

2. If you want to tune the carb follow the instructions here....

http://www.hitchcocksmotorcycles.com/mo ... to-tune-up

If it's not a monobloc the basic principles for the Monobloc still apply but there are other instructions on that same web site

3. Do not use a resistor plug or resistor plug cap or a carbon HT lead with a magneto. The HT lead should have a solid copper conducting core, not a carbon core as with modern HT cable. Whether you use a B7ES or a B6ES will IMHO make little difference. I have a B7ES in my '54 G3LS.

4. The ammeter will not show a charge all the while the battery remains fully charged and the dynamo output matches the bike's electrical demand. With lights switched on the ammeter is likely to show a discharge at speeds below 35 to 40mph in 4th since the engine is not driving the dynamo fast enough to generate sufficient output to balance the drain of the lights. Likewise with no lights on and a fully charged battery the ammeter will not show a charge because the battery doesn't need charging and the regulator will reduce the output of the dynamo accordingly. Obviously since your ignition is by magneto and not from a battery and coil the ignition system will not be requiring power from the battery at any time.

5. Find the Workshop Manual, Parts list and Owners Manual on Christians Archive here...

http://archives.jampot.dk/book/

5a. Only put sufficient oil in the chaincase so that it reaches the bottom of the lower run of the primary chain and definitely no higher.

5b.Contact your local section if you can.
'There is a tide in the affairs of men
Which taken at the flood............'
Mick D
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Re: Matchless G3LS 1953 questions

Post by Mick D »

Hi

Tick-over speed is set by the throttle stop screw, (knurled screw entering the carb at an angle beside the main jet holder and with a spring on it - assuming you have a Monobloc carb fitted). With the engine up to temperature and the bike on the centre stand screw in to increase the tick-over speed. I'd try this first before delving deeper into the internals of the carb. The anomaly of not stalling when on the side stand is probably explained by the float / needle valve assembly not functioning 100% at this un-natural position.

I don't have too much confidence in the accuracy of the ammeter - provided it is not showing a discharge when riding with the lights on I'd be tempted to monitor the condition of the battery with a multi-meter and only investigate further if it proves to be deteriorating.

If you search the forum there was a fairly recent topic where people itemised the spark plugs they currently use.

Regards Mick
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thornebt
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Re: Matchless G3LS 1953 questions

Post by thornebt »

The NGK equivalent for KLG is B7ES as you say. A good upgrade is B7EV which has a gold palladium electrode. It has a lower voltage requirement (will spark more easily), is more resistant to fouling and will last longer. They are not very easy to find at a good price these days. Cheers. Bruce.
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Rob Harknett
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Re: Matchless G3LS 1953 questions

Post by Rob Harknett »

The bike is 1953. Monobloc carb is 55. But who knows what carb this bike may have. The 1953 instruction book has a nice exploded view of the ( correct ) carb with all parts named. But what ever carb you may have, the throttle stop screw may not be what you need to adjust. Check cables and slides. Is the choke cable adjusted so the slide can be fully opened up. Let off the throttle slide stop, make sure the throttle cable is adjusted so the throttle slide will fully close. Now you can adjust the air screw mixture and throttle stop screw. On the correct carb there is a lock nut. You will of cause need other settings correct, also have correct parts fitted. Slide, jets etc. All slides may look the same but the cut away matters. No advise may help, unless you have the correct parts.
Jonny Astro
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Re: Matchless G3LS 1953 questions

Post by Jonny Astro »

Thanks for all the sage advice everyone!

I'll tweak the screw in the chain case clamp a bit more forcefully. The leak is small so I'm not overly concerned, but let's be sure everything is secure.

I've bought a B7EV plug - I'm going to fit this before I mess with the carb, (which is the original "standard" Amal by the way, not a monobloc).

And I now understand about the ammeter - make sense of course.

Two small supplementary questions:

1/ The dualseat is retained by two bigheaded knurled screws at the back, and from what I can see there are two forked "prongs" at the front, pinched by a transverse bolt. So all I need to do is loosen the bolt head/nut - But the heads of the bolt are all-but inaccessible by spanner due to the deep sides of the saddle... Am I missing something or have I just got to get dextrously creative with an open-ender?

2/ Given how recently the engine was rebuilt, I guess it would be a good idea to go around tightening bolts before too long? The cylinder base nuts are easy of course, but presume I have to get inside the rocker boxes to get at the head bolts? Maybe at 500 miles?

Jon
SPRIDDLER
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Re: Matchless G3LS 1953 questions

Post by SPRIDDLER »

Jonny Astro wrote:Thanks for all the sage advice everyone!

I'll tweak the screw in the chain case clamp a bit more forcefully. The leak is small so I'm not overly concerned, but let's be sure everything is secure.
The club can supply a profiled sealing band which by reputation is the best there is.
1/ The dualseat
I know the problem and use a socket on a short extension bar. If you don't want the expense of a socket set a box spanner will do it. Don't ask me the size as I never look at markings on spanners. I have fettled every bit of my bikes so often for so many years that I know by sight now which spanner or socket to pick up for each bolt or nut.
2/ Given how recently the engine was rebuilt, I guess it would be a good idea to go around tightening bolts before too long? The cylinder base nuts are easy of course, but presume I have to get inside the rocker boxes to get at the head bolts? Maybe at 500 miles?
You do indeed. Normally earlier than that. I do mine by cracking the bolts back just a smidge then retightening to 30ft/lbs after around 6 hours running (say 200 miles). The copper head gasket will (should) have been annealed (softened by heating) before fitting but it will now have hardened so you probably won't be able to pull the head down by much. Handy to have another rocker cover gasket ready. You'll also need three spanners (one quite thin) to reset the pushrod/valve rocker clearances.
Be cautious tightening the rocker cover bolts as they go into the relatively soft alloy cylinder head. Make sure that the blind rocker cover bolt holes are clean to their bottom as crud can build up which means that although the bolt feels tight it can be simply stopping at the crud at the bottom of the hole before compressing the rocker cover gasket sufficiently. I don't use a torque wrench on these, just a short ring or open ended spanner depending upon which bolt, but I've read the recommended figure to be 10ft/lbs.
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Which taken at the flood............'
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Pharisee
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Re: Matchless G3LS 1953 questions

Post by Pharisee »

SPRIDDLER wrote: I know the problem and use a socket on a short extension bar. If you don't want the expense of a socket set a box spanner will do it. Don't ask me the size as I never look at markings on spanners. I have fettled every bit of my bikes so often for so many years that I know by sight now which spanner or socket to pick up for each bolt or nut.
You'll need a 3/8" Whitworth / 7/16" BSF box or socket spanner (with extension)... probably two as you'll need one each side.
I'm from the Fens.... Gimme six.
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