Adjustment of oil feed

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Adjustment of oil feed

Postby onthebuses » Tue Nov 14, 2017 9:38 pm

Hi I've finally got it running but the top end sounds a bit noisy ..... Manual states one sixth from fully closed but fully closed only is possible without the locknut restricting it .... And if the screw is fully removed whilst the engine is running should oil pour out ( it doesn't) Thanks in advance Gary

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Re: Adjustment of oil feed

Postby bjork » Tue Nov 14, 2017 10:22 pm

Not quite clear what you mean about the locknut restricting it, but start at a quarter turn out. It won't pour out when the screw is removed as it's not a pressure fed thing. It just collects oil flinging about the rocker box and then meters it (via that screw) under gravity to the valve guide.
They can get blocked with carbonised oil muck over time. If you start at a quarter turn out then ride it a little you'll get clues about what to do next. A squeaking means you need more oil and oil in the exhaust or smoke means less is needed. Hope that helps.
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Re: Adjustment of oil feed

Postby Rob Harknett » Wed Nov 15, 2017 12:21 am

Are you saying, with the screw fully tightened there is no thread left for the lock nut to go on ? If so perhaps the screw has been broken or someone has stuck a drill in the hole. Show a pic of the screw with dimensions, if its needs checking.

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Re: Adjustment of oil feed

Postby clive » Wed Nov 15, 2017 9:52 am

In my experience some of the adjusters are longer than others. If you can get away with partial use of the lock nut it will probably be fine. I have driven some miles back from a Jampot with a piece of stick wound into the hole after one vibrated off.
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Re: Adjustment of oil feed

Postby SPRIDDLER » Wed Nov 15, 2017 10:47 am

Maybe someone has been a bit creative and replaced it with the wrong screw.
It's not just like a standard bolt with the head removed but has a reduced dia. shank and a pointy end.

Inlet valve feed screw.JPG
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Re: Adjustment of oil feed

Postby Rob Harknett » Wed Nov 15, 2017 1:21 pm

That was my thought Neville, but I could not find a picture, so asked for a pic, of the parts that do not seem to be correct.

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Re: Adjustment of oil feed

Postby SPRIDDLER » Wed Nov 15, 2017 4:17 pm

I've just whipped mine out for the first time in well over 10 years):

2017-11-15 inlet valve oil dims 007 (840x630).jpg



2017-11-15 inlet valve oil dims 009 (740x555).jpg


and there are about 4 threads showing above the nut when fitted and 1/6th open.

2017-11-15 inlet valve oil dims 003 (840x630).jpg
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Re: Adjustment of oil feed

Postby onthebuses » Wed Nov 15, 2017 4:49 pm

Thanks for that ill measure mine and compare ....... It completed 27 miles yesterday its first run since 1969. Not sure what to expect but top end did sound a bit noisy and she did appear to be running hot ... Plug colour looks good but my this is out of my era so I'm on a bit off a learning curve. Thanks to everyone for their help

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Re: Adjustment of oil feed

Postby onthebuses » Wed Nov 15, 2017 5:05 pm

Thanks for that ill measure mine and compare ....... It completed 27 miles yesterday its first run since 1969. Not sure what to expect but top end did sound a bit noisy and she did appear to be running hot ... Plug colour looks good but my this is out of my era so I'm on a bit off a learning curve. Thanks to everyone for their help

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Re: Adjustment of oil feed

Postby SPRIDDLER » Wed Nov 15, 2017 5:11 pm

It depends what sort of noise you have. The things that are most likely to make an untoward top end noise are an oversize pushrod to rocker gap (should be zero gap warm but p/rod can still be turned easily with fingers) or the decompressor cable is badly adjusted (no slack) so that the zorst valve is contacting the decompressor shaft, or the hairpin (?) valve springs are incorrectly fitted and tapping on the rocker box (look for witness marks). Piston slap is also a possibility, especially on start-up when the engine's cold.
Overheating can be as a result of retarded ignition timing (you did set the ign timing with the A/R lever at full advance didn't you?), weak mixture..................
I assume you have the Owners Manual and the Workshop Manual?
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