WD G3

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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moley
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Location: EAST SUSSEX UK

WD G3

Post by moley »

Evening all

I am looking at my friends bike, his main problem is that no oil is going up the rocker feed pipe.

The bike is returning oil - sort of small constant pulse which I understand is normal but no oil to the rockers.

I have double checked oil pump is in good condition, guide pin is NOS and the pump goes forwards and backwards, front pump plate is clear with no blockages.

Any Ideas ??

Cheers

Andy
SPRIDDLER
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Re: WD G3

Post by SPRIDDLER »

A bit of background might help. Is the bike new to him? Has oil ever reached the rockers? If so, what has he done to the engine since (apart from fitting the new guide pin).

Is the new guide pin fitted the correct way round? If not then the oscillation of the plunger will be reduced.

You said the front plate isn't blocked but have you removed it? There is a feed hole in the pump front plate. If the gasket hasn't been fitted with the hole matching its position in the front plate no oil will get to the rocker box.
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Rob Harknett
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Re: WD G3

Post by Rob Harknett »

Those front plates corrode, buckle and get damaged, if it leaks, try flattening it on sand paper on a flat surface. When the whole surface shows its been sanded, it's flat. Use a new gasket. Also check the rubber pipe joiner is OK. Dip one end of the complete pipe in water and blow through the other end. You should ses bubbles coming out and / or muck. The top end needs very little oil
Dixter
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Re: WD G3

Post by Dixter »

Andy, The oil delivery to the rockers is minuscule even on a fresh engine under ideal circumstances. If for example, one were to remove the rocker box cover on a cold engine, start the engine and look for oil dribbling from the brass jets where the rockers meet the push rods, waiting several minutes would be normal.

Kindly tell us how you are testing the degree of pumping? Please be quite specific.

Thank you,
DC
Dick Casey
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moley
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Re: WD G3

Post by moley »

Hi , I have the feed pipe removed but the pump plate still attached to the engine and run up the bike hoping to see oil appear and overflow the oil pump front plate but nothing appears.

I thought of sort of priming it by backfilling oil through the front union but as soon as you kick the bike the oil disappears back into the union

Andy
Mick D
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Re: WD G3

Post by Mick D »

Hi

Have you confirmed the guide pin is installed correctly as suggested by Spriddler? It goes in with the greater diameter uppermost.

Regards Mick
moley
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Re: WD G3

Post by moley »

Yes guide pin is in as described cheers andy
Dixter
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Location: Seattle area, WA USA

Re: WD G3

Post by Dixter »

Hi Andy, thanks for the explanation. At the forward pump plate, I would expect to see oil within 5 - 10 seconds of running. Next step I'd make would be to pull the front plate off and inspect the placement of the paper gasket, looking to see if the port on the front plate was blocked.

Next I'd verify the pump plate is not blocked between the gasket surface and the threaded outlet on the pump plate.

Lastly, with a twist drill bit in my fingers, spin a clean drill bit in the crankcase oil galleries to see if some silicone gasket goo or similar is blocking. Silicone in these engines is not encouraged.

Happy hunting,
DC

NB The oil pump on these engines makes one pumping stroke after the crank shaft has made eight full revolutions. They are maddening slow. In their defense, they are long lasting and reliable.
Dick Casey
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Dixter
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Re: WD G3

Post by Dixter »

Bump...

Yo Andy, what ever happened? Were you able to solve the problem, if so, what did you find?

Ciao, DC
Dick Casey
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