Model 14 no oil return???

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
geoffb-63
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Location: Cleveland, UK.

Model 14 no oil return???

Post by geoffb-63 »

Hi to all, further to my previous post`s, regards to a project i purchased, i have now bought another, quite nice complete, 1961 Model 14, "the one that was advertised in the for sale section" the bike is starts and runs ok but according to the previous owner, he does not think the oil is returning as it should, the oil and filters have been done, unfortunately, there is no sign of oil returning back to the tank, the engine has only been run a couple of times, for a very short time, as he was concerned about possible damage to the engine, obviously, no sign of any return oil, as a novice on these bikes, can someone please help with what i need to do/check to ensure everything is ok.
Regards.
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Ozmadman
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Location: ESSEX UK

Re: Model 14 no oil return???

Post by Ozmadman »

Could be a worn oil pump pin, it is a reciprocating pump that relies on a pin running in a groove in the pump shaft which creates a forward and backward motion as it turns. The movement is not much even when new so a worn pin in the groove could mean little or no movement. It could also be worn teeth on the oil pump shaft itself but you would need to take the gearbox out to get to the pump (it comes out at the back of the engine) to check. If the filter has been changed make sure the washer down the end of the oil filter tunnel is not canted as this could block the feed hole to the filter. Do you have oil feed to the rockers? a worn pin can reduce or stop oil feed to them. Take the filter out and run it, at least you can take that out of the equation if there is still no return. I am presuming you have sufficient oil in the first place. Has the oil pump or pin been played around with? as it is easy to damage the pump if the pin is not located correctly.. Here is an extract from the manual

Fitting the oil pump plunger. If there is evidence of bad
tooth marking the plunger should be replaced. Examine
also the hardened guide pin 010079, a flat worn on the
extreme end will curtail oil supply to the rocker box.
Put some clean oil on the oil pump plunger, insert it into the
crankcase to a depth of l i s " from the end of the plunger to the
face for the washer 042178. Fit the screwed body (using the
fingers only) with extreme care to locate the guide pin in the
annular groove in the pump plunger. A spanner to tighten
must not be used until it is certain that the guide pin is correctly
located. Omission to observe these instructions can damage
the pump gear beyond further use.
Fit the housing plug 042045 with its washer and firmly
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
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clanger9
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Re: Model 14 no oil return???

Post by clanger9 »

I'd agree with Paul. It's not easy to check the oil pump motion without major dismantling.
To check it without removing the engine, I'd suggest removing the outer cover and the oil tank. Then you can remove the bolt (042046) and the plug (042044) on the right-hand end of the oil pump. Don't remove the oil pump guide pin (010138) yet.
Now turn the engine over by hand and you should be able to feel/observe the pump plunger going up and down through the hole where the plug was...
Untitled.jpeg
Good luck!
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1989 Moto Morini Dart 350
1993 Ducati 750SS
shifter
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Location: NORTH

Re: Model 14 no oil return???

Post by shifter »

Hello Geoff
Tis me you bought the bike off I hope our phone conversations were clear and of some help to you as you already know you will get all the help and advice from the members you need.Paul I hope you are right with the filter washer its never happened to me before but theirs always a first. The bike had been standing for quite a time so I changed the oil (plenty in) 1/2 inch below the rtn hole, filter was cleaned replaced bike started easy ran nice but after a short time of running no oil rtn so switched it off and before I could investigate I got news my storage was being sold off so had to sell a cpl of bikes this being one.
Last edited by shifter on Thu Oct 26, 2017 1:29 pm, edited 2 times in total.
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Ozmadman
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Location: ESSEX UK

Re: Model 14 no oil return???

Post by Ozmadman »

Good Idea!! just make sure that little o ring fitted to (042044) is intact before you push it back. At least from here you can check the guide pin (010138) if there is little movement as ANY wear even minute can have an adverse effect and TBH I would replace it anyway as you have got this far. It may be difficult to pull it out of the retaining bolt because of hydraulics and when it goes back the wide end fits in the pump groove. be very careful when you try to screw the bolt and guide pin back ANY resistance means the pin is not slotted in the groove in the pump you can move the engine rotation back and forth a tad until that bolt screws in easily. Take your time otherwise you could cause damage and a lot of grief. If you remove that bolt and pin and don't touch the engine at all then it should just go straight back.. Let us know how you get on
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
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Ozmadman
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Location: ESSEX UK

Re: Model 14 no oil return???

Post by Ozmadman »

shifter wrote:Hello Geoff
Tis me you bought the bike off I hope our phone conversations were clear and of some help to you as you already know you will get all the help and advice from the members.Paul I hope you are right with the filter washer its never happened to me before but theirs always a first. The bike had been standing for quite a time so I changed the oil (plenty in) 1/2 inch below the rtn hole, filter was cleaned replaced bike started easy ran nice but after a short time of running no oil rtn so switched it off and before i could investigate I got news my storage was being sold on so had to sell a cpl of bikes this being one.
How long did you run it for??
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
shifter
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Re: Model 14 no oil return???

Post by shifter »

Aprox 3/4 mins on 2 separate times I have not had this problem before with other lightweights in the past they all have had the oil returning after just a cpl of mins
Last edited by shifter on Thu Oct 26, 2017 11:50 am, edited 2 times in total.
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SPRIDDLER
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Re: Model 14 no oil return???

Post by SPRIDDLER »

This has been raised many many times. You need to run th'engine for a while. It can take 7 or 8 mins on fast tickover.
See Clive's post below from 2014 in the 'Frequent questions' section which may help you:

http://www.jampot.com/forum/viewtopic.php?f=8&t=13368

of course it could still be a mechanical/blockage issue.
'There is a tide in the affairs of men
Which taken at the flood............'
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clive
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Re: Model 14 no oil return???

Post by clive »

Sprids that was on a heavyweight single not sure if it applies to the lightweight engine.
clive
if it ain't broke don't fix
SPRIDDLER
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Re: Model 14 no oil return???

Post by SPRIDDLER »

clive wrote:Sprids that was on a heavyweight single not sure if it applies to the lightweight engine.
Yes, I did wonder about that as the oil reservoir on the L/Weight is lower than the tank on the H/Weight. The pump's the same though.
P'raps best to ignore my post as I don't want to mislead..........
Do the Lightweight engines suffer from wet sumping?
'There is a tide in the affairs of men
Which taken at the flood............'
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