Matchless G2 oil return

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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John A Hirst
Posts: 5
Joined: Mon Jan 01, 1990 12:00 am
Location: WEST YORKSHIRE UK

Matchless G2 oil return

Post by John A Hirst »

Hi. I have just rebuilt a Matchless G2 1965. I got the bike running without too much trouble and was quite pleased with myself, then I noticed oil running out from behind the points, this can only come from, either the drain hole in the camshaft housing or from the oil seal. I took the points off and the outer camshaft housing to see what was amiss. Can anyone out there tell me how does the oil in the camshaft housing drain back to the pump ??? I know that when you get a bit older your eyesight starts to go but this is ridiculous.
Allan.
good-hifi
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Joined: Thu Jun 08, 2006 9:14 pm
Location: OXON UK

Matchless G2 oil return

Post by good-hifi »

I just had a look at a spare one I have here.

There is no drain hole but I suspect that all the movement in the crankcase/cam housing ensures that the oil is changing pretty often as it is splashed and thrown around.

Cheers

Mick
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chris kelly
Posts: 288
Joined: Mon Jan 01, 1996 12:00 am
Location: OSTERGOTLAND SWEDEN

Matchless G2 oil return

Post by chris kelly »

Hi, Here is a quote from the Illustrated Instruction Book, "Engine Lubrication System. This is by true dry sump system,The oil tank, or reservoir, is integral with the crankcase.The oil pump has only one moving part, ie, the oil pump plunger, which rotates and reciprocates. Rotation is created by the worm gear on the timing side flywheel axle.Reciprocation is caused by engagement of the oil pump guide pin with the profiled groove in the oil pump plunger.The oil pump is designed so that the sump scavenger capacityis greater than the delivery, thus keeping the crankcase sump free of oil during normal running conditions. Whilst the oil reservoir is integral with the crankcase, oil is fed to the pump by gravity, on the same principle as a machine fitted with a separate oil tank, but without the use of external oil pipes. Engine Oil Pump. If for any reason, the crankcase is dismantled the oil pump plunger must be removed from its housing before attempting to separate the crankcase halves. It is also necessary to remove the small timing pinion. IMPORTANT. Under no circumstances must either the pump plunger or guide screw be disturbed in ordinary routine maintenance. ENGINE OIL CIRCULATION. THE OIL PUMPFORCES OIL THROUGH ___ A) Passages drilled through the timing side flywheel axle, timing side flywheel and crank pin to lubricate the timing side bearing and the big end bearing.The splash passes to interior of cylinder , to lubricate the cylinder and piston and then falls into the crankcase sump. B) From the front oil pump housing to the rocker box via passages in the cylinder barrel lubricating the rocker gear and valve stems. Oil from the rocker gear drainsby gravity via the the push rod tunnels to the timing gear case at a pre determined level.The over spill drains into the crankcase sump. C) The oil pump extracts oil from the crankcase sump, metal impurities are collected by a magnetic filter in the sump drain plug. The oil is again filtered bya felt filter located in the the crankcase before returning to the oil tank reservoir. etc, etc and " The normal oil level is one inch below the filler cap orifice, the oil content is two and a half pints " Any clues here ?? Chris.
'My cat can beat up your cat!'
alan
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Posts: 77
Joined: Fri Aug 20, 2004 1:00 am
Location: CHESHIRE UK

Matchless G2 oil return

Post by alan »

hi allan,
i think you will find that you will have to replace the oil seal. i have pasted a link below to an exploded view view of the g2/csr engine, this will help you to identify the seal.
link is from christians site hope it works.
regards, alan
http://217.157.196.176:8181/ajs/Technic ... _drawings/
John A Hirst
Posts: 5
Joined: Mon Jan 01, 1990 12:00 am
Location: WEST YORKSHIRE UK

Matchless G2 oil return

Post by John A Hirst »

Hi folks, thanks for the info.
I have replaced the oilseal with a new one, and as there is no way out of the camshaft housing except one tiny hole in the back of the points chamber (I suspect this hole is to drain any oil that might get into the points chamber, back into the camshaft housing) there is bound to be a build up of oil.
There is a way into the oil pump but this is completely covered over by the camshaft outer cover, this is in the bottom right hand corner.
thanks
Allan
alan
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Posts: 77
Joined: Fri Aug 20, 2004 1:00 am
Location: CHESHIRE UK

Matchless G2 oil return

Post by alan »

hi again,
is there a lot of oil coming out of the points chamber? if so do you think the engine may be building up too much pressure? also i read somewhere that on some of the later bikes, a hole in the oil tank had not been drilled, i dont mean the oil return hole.
i will see if i can get anymore info on that, it just may help.
regards,
alan
John A Hirst
Posts: 5
Joined: Mon Jan 01, 1990 12:00 am
Location: WEST YORKSHIRE UK

Matchless G2 oil return

Post by John A Hirst »

hi alan
yes there is a lot of oil coming out of the points chamber, it is not put there by preasure, but what drains down from the head to lubricate the rockers and the push rods and the camfollowers but then I can't see where it goes to carry on circulating.
I also read about this hole in the oil tank and when the engine was in pieces I checked this out and low and behold there it was.
Thanks anyway,
allan
alan
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Posts: 77
Joined: Fri Aug 20, 2004 1:00 am
Location: CHESHIRE UK

Matchless G2 oil return

Post by alan »

hi,
just another thought,do you have the screw that controls the oil feed to the rockers turned right down, "allmost tight" as it can cause over oiling in a big way at the top end, and that may be the problem too much oil running back down from the head.
apart from that i am as stumped as you.
please post back the fix if you find one.
good luck
regards,
alan
John A Hirst
Posts: 5
Joined: Mon Jan 01, 1990 12:00 am
Location: WEST YORKSHIRE UK

Matchless G2 oil return

Post by John A Hirst »

Hi Alan
I have screwed the control screw down and just opened it slightly but I don't want to put it back together untill I know where the oil is supposed to go.
Allan
John A Hirst
Posts: 5
Joined: Mon Jan 01, 1990 12:00 am
Location: WEST YORKSHIRE UK

Matchless G2 oil return

Post by John A Hirst »

Hello again.

I have found out, that my problem was that the previous owner had drilled a hole where there should not be a hole, allowing the oil to enter the points chamber from behind the auto advance.

The oil return hole was there all the time but I could not see it for the rockers

The oil return is by a hole in the crank case behind the camfollowers, this meens that the pinion gear, the cams and followers are all immersed in oil.

regards Allan

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