Matchless G3LS 1953 questions

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
Jonny Astro
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Joined: Sat Oct 07, 2017 4:13 pm
Location: BERKSHIRE UK

Re: Matchless G3LS 1953 questions

Post by Jonny Astro »

Me again!

My 1953 G3LS is running really nicely, especially since fitting the monobloc carb. Just approaching 500 miles since it's rebuild by the previous owner, so I thought I'd give it the once over - change the oil, check the timing, etc. Questions:

1/ Do I need to drain the sump or would it be OK to just change the oil in the tank?

2/ Will I need to use a new primary case seal after checking the chain or are they re-useable?

3/ I gather that ignition timing is 7/16" or 1/2" BTDC, but given that the spark plug hole, through which I will poke my depth gauge, is at about 45 degrees to the stroke axis, do I need to do some trigonometry or is that measurement taking the angle into account?

Jon
Mick D
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Re: Matchless G3LS 1953 questions

Post by Mick D »

Hi

1/ I'd drain the sump too - it will allow you to ascertain there are no horrors lurking - if you see any metallic debris in the sump oil it would be cause for further investigation.

2/ I'd only check / adjust the chain tension - doesn't your chain case have an inspection port to facilitate this? If this is the gasket to which you refer, I'd have one standing by but have a go at re-using the original.

3/ The dimensions are 'vertical' as I understand - just rest your depth gauge on the inboard side of the plug hole and keep it vertical-ish and you'll be OK.

Regards Mick
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spookefoote1956
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Re: Matchless G3LS 1953 questions

Post by spookefoote1956 »

Try cleaning the carb with some wynns carb cleaner. Sorted mine out a treat.
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Jonny Astro
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Joined: Sat Oct 07, 2017 4:13 pm
Location: BERKSHIRE UK

Re: Matchless G3LS 1953 questions

Post by Jonny Astro »

My 1953 G3LS has done about 500 miles now since it was rebuilt by the previous owner, and I finally got around to giving it a "light service". Changed the oil in the tank and sump - no nasty surprises.
Pulled the primary case cover too - the primary chain tension felt spot-on, but the dynamo chain was VERY slack. Eventually worked out which was the dyno clamp nut and rotated the body to find the best adjustment.
So far, so good - now to replace the cover! It had a modern-looking rubber seal fitted but this was leaking very slightly, so I ordered a new one from the club shop - it's different. The new one's material is less dense (neoprene?) and the "T" section does not follow the contours of the case or cover so closely.
Main issues are that instead of being a closed loop the club seal is just a straight length, (i.e. not "joined up" like the one I took off) and the part of the seal's section which will be in compression seems to be thicker.
Questions:
Just cut to length and have the ends meet up along the top edge? Hope the clamp will keep the oil in?
Do I need to "adjust" the amount by which the main retaining nut compresses the new seal? Or will it's softer density mean I can just tighten it like it was before?
Jonny
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dave16mct
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Location: LANCASHIRE UK

Re: Matchless G3LS 1953 questions

Post by dave16mct »

Put the join at the top, you may need to shorten it a bit. Add a couple of washers behind the centre stud.
Dave.
56G80S
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Re: Matchless G3LS 1953 questions

Post by 56G80S »

"just rest your depth gauge on the inboard side of the plug hole and keep it vertical-ish and you'll be OK."

Mick's spot on. Personally, I use a length of stiff wire (with the top bent in such a way that it can't fall in) and put two small nicks from a triangular file once I've marked my TDC with sharp pencil.

On the dynamo, hope you haven't overtighten the bolt on the strap, it will bend the rod between the engine plates at the bottom part of the strap. It's equally important to re-check for tight spot once you think you've finished. Be sure that the primary and dynamo chain runs are lined up properly with the engine sprocket; I experienced (long ago) the result of the chains clashing and it's not nice. Others will disagree about it's value, but thanks to a drawing by Don Madden, I made and used the "flat steel" strip that locates the dynamo and stops it wandering into the chaincase. I think Club spares has these now.

But, I recall the comment by Biscuit (a now deceased but knowledgeable Club member) who said that generally more problems are caused by chains being slightly tight than ones being slightly slack. It's easy to bend the dynamo armature or wreck the small bearings.

Johnny B
Wayne Cole
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Re: Matchless G3LS 1953 questions

Post by Wayne Cole »

g5wqian wrote: Sat Dec 30, 2017 8:45 am champion N5C plug is better , will burn off and run hotter .

re the primary cover , i have no sealant on mine and use the clubs foam rubber new type seal and it doesnt leak , but there are other holes in the rear of the backplate that could leak if not sealed .
it may not be the primary thats leaking though , could be gearbox if its a burman box , my burman leaks and took some time to work out where the oil came from as i was thinking it was the chain cover .

with the carb youll find it runs slow when cold and then speeds up when engine warms up , but you may well need to turn up the idle speed before starting , by around 3/4 turn and then it will idle cold , then when engine warms up back off the idle speed .
idle screw is easy to adjust externally if you have a monobloc carb , its the bigger screw facing downwards .

putting bike on sidestand makes mine run bad unless idle speed is high , it will usually stutter and conk out if left on sidestand but runs ok with the centre stand .
you may be able to adjust the float level or check it , if its a pre monobloc carb it may be easier to check it out , but also remember to check float bowl for rusty sediment and clean out if necessary .
i have an old senspray carb on my older bike and the very fine sediment of rust from inside the tank gets past the filter and now and again it will conk out , so i will have to take the float out and clean bottom of the float bowl of sediment before it goes again ..


be carefull leaving bike running as if mine revs above a certain level it will move backwards on the stand .

you really do need to use the retard when starting or some time youll get a nasty kick back .

ammeter -- depends on whether it is a 8-0-8 amp type and what the dynamo is , but dynamo may well be a 60w type i guess , and if the ammeter is a good old one or a new one made recently .
i had to replace my ammeter when the moving coil fell apart , so i put one of the new lucas ones on there , but at same time id had my dynamo off and rebuilt it due to oil getting in from the timing cover on my particular model .

did have to swap wires on ammeter round though as the new one is wired opposite way round to previous one .

running with the 35w bpf bulb i find ammeter drops minus 4 amps at idle when light is on and when bike revs up it goes to zero and into the + side , and with light off it goes to plus 4 amps charging .

i did reflash the polarity of dynamo after rebuild , easy job just disconnect the negative wire from battery [the non earthed one ] if its positive earth .
remove the wires from dynamo socket and with a piece of wire connected to the -ve battery terminal you flash other end of wire on the F terminal of dynamo a few times for a second or so each time , it should make a flash each time you swipe the bare end of wire over the F terminal , this is then polarised for pos earth.

with the new lucas ammeter i found it moves slowly compared to the old ammeter i had , and because i rebuilt the dynamo i did flash it 2 separate times and had to put a fair load [35w bulb] on it before it would charge to a higher degree although it does have new brushes in which may have required a run up for a few minutes before bedding in to the armature .
seems to work fine now .
i was running a LED headlight bulb but after putting the filament type back in again it looks like i have a better pattern with the old style bulb so am going to try it out for a while and see which is better for me at night .
i dont do much night riding but the last time i rode from oxford to swindon in the dark it was not the best of trips with the LED light not giving me the type of beam i should expect , and i had played with a couple of headlight units and found the lucas one to be best pattern with the LED but never tried the old bpf bulb in the new lamp so will give that a go .

i do ride down near you neck of the woods when the weathers better , usually around chilton foliat and hungerford and newbury area , quite good lanes around there to have a look around and good views .
if you go up above ramsbury you can still get on the old wartime airstrip and have a quick blast along it , missing the pot holes as you go .

regards
ian
sorry to drag up an old post, please may I ask what the club foam thing is and where to get one?
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clive
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Re: Matchless G3LS 1953 questions

Post by clive »

Welcome to the forum. Foam sealant for the chaincase, available through the club spares scheme which is open for purchases by paid up members.
clive
if it ain't broke don't fix
g5wqian
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Re: Matchless G3LS 1953 questions

Post by g5wqian »

hi jon ;

https://www.amoc-parts.com/store/comers ... duct=23441

should be this seal in link above , for tin primary chain case , it is a foam type seal , all i did was to put the join at the top middle with a bit of silicone between the 2 ends where they meet , i did not put any sealant around the seal itself , i just put the seal on the chaincase dry and it worked great .

much better than a solid rubber one .

link below to main primary chain case spares page with more bits on .

https://www.amoc-parts.com/store/comers ... ategory=61

ian
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