AJS & Matchless Owners Club

Can somebody tell me if the guide pin threaded body has a fibre washer fitted under the hex. head or is it designed to go fully home.

I've got a thin fibre one on mine

Just so you have both answers: No washer as it affects the amount the guide pin contacts the pump.

No fibre washer listed in parts list. Never fitted one to any of my singles over the last 39 years. So its 2:1.

Thanks for the replies gents, as Clive points out there is no ref. to one in the parts book and that prompted me to ask the question.

No fibre washer on mine.

Johnny B

I correct myself and apologise from the heart of my bottom. I don't have a washer either.

Dropped the guide screw body today and found the guide pin had been put the wrong way into the holder and it also had a fibre washer fitted under the holder head.
Turned the guide pin the correct way and removed the washer but the holder or guide pin now tightens on the plunger before screwing fully home so it stops the slight to and fro movement of the plunger when pressed at the ends.
Reading the manual the plunger can be withdrawn from the rear end of its housing, am I reading that right?, and if thats the case is there a special way to reinsert the plunger to engage with the guide pin.

Hi

The workshop manual has this advice:

'Refitting the oil pump plunger. First renew the paper
gaskets on the pump end caps, stick the gaskets to the plates
with jointing compound.
Remove burrs or particles of old gasket from crankcase
faces. Take up the oil pump plunger, oil it and insert in
crankcase. Clean the interior of screwed body (6) (Fig. 1).
Oil and insert guide pin (5) as illustrated, the pin should
revolve freely. Fit the screwed body and pin with extreme
care to ensure the guide pin is located in the annular groove
in the pump plunger, using the finger to do so. It may be
necessary to revolve the flywheels to locate the pin. The
screwed body can be finally tightened with a spanner. Failure
to observe these important instructions can ruin the pump gear
beyond further use. Now fit the two end caps'.

You should be able to gently push the pin in whilst moving the plunger fore and aft to 'feel' it locate.

Regards Mick

Arty you say the pin was inserted the wrong way. The correct way is with the shouldered section inserted into the holder. Put it in the other way and there is a risk that oil in the holder will stop it going fully home, and the other end, being stepped, will not induce enough movement in the oil pump.