AJS & Matchless Owners Club

Just a thought: the rocker oil holes were deleted on later cylinder heads. If your bike has a late-style head, there may not be any holes.

oh - ok

our engine number is 61/G2 10529
being 1961 I assume it is an early engine with jets then ??

thank you anyway

If you can see the jets (like in Paul's video), it has jets.
In my photo, you can see that the castings above the rockers have no jets.

It was just a thought, because cylinder heads can get swapped around...

clanger9 wrote:If you can see the jets (like in Paul's video), it has jets.
In my photo, you can see that the castings above the rockers have no jets.

It was just a thought, because cylinder heads can get swapped around...

Forgot about that!!! where does the rocker oil feed come from on those heads or doesn't it?

It just drips from behind the rocker arm flanges. Oil feed still seems healthy enough, there's always oil on the pushrod ends.

hi all,
just a delay on this topic , but thank you all for your thoughts exasperation/frustration is creeping in now !!

ok - oil holes poked out all clear

rocker inspection cover off and engine running - nothing coming from the oil jets above the pushrod cups -

BUT plenty of oil splashing about generally - oil drips from rocker spindles and pushrod cups generally wet and plenty splashing about - but nothing out of the jets

rocker cover off - gasket correct oil way right way round - poke downwards about a mile down to crankshaft depth

oil can nozzle into rocker cover oil entry hole and I can push oil out of the 3 little jets - 2 above pushrod cups and the 1 which squirts onto the exhaust valve area - so all 3 holes obviously clear.

there is quite obviously oil getting up there as the spindle drips oil when it's running - but not enough to come out of the jets.

I have screwed the metering screw right in and back out about 1/2 to 1 turn and I'm pretty sure that I can see oil coming out of a hole just internally and vertically above the metering screw - it squirts upwards toward the inlet rocker - should it come out of here please?? as this will bleed oil pressure off.

the return side - I have removed and cleaned the filter element - I have momentarily run the engine without the filter and chrome cap in place and loads of oil is scavenged into that filter tube - replaced the filter and plenty scavenged back into the tank little oil hole.

am I losing the head oil pressure somewhere?? if so where please - it's as if its there but disappearing before it gets out of the jets -

the rocker spindles are snug and firm with no slop or float obvious - I thought if they were sloppy it would bleed out there and not the jets

sorry for length of post - any ideas gratefully received.

I've just seen someone else's thread about the 5th head bolt ---
Re: Length of "extra" Lightweight head bolt

"Postby clanger9 » Sun Feb 04, 2018 7:05 pm

Not at all - I can certainly figure it out by measuring the depth, etc. 5/16" BSF x 3" seems "about right".

I could do with the dimensions of an original so I know how deep the bolt is supposed to go into the block. My guess is (as Paul says) that it doesn't need to be especially tight and it's just there to keep the oil feed to the head leak-free."

could that be the reason ??? as my bolt (I've just discovered) is missing

I can confirm that the 5th head bolt is 5/16" BSF x 3". Make sure the tapping in the barrel is clear of any crud before you fit it.

I made a handy list of Lightweight fastener sizes here (if you spot any errors, please feel free to correct them!):
https://1drv.ms/x/s!AreW5w5WmJsqrFeLbZTlUbrrf_C7

Thinking about your oiling issue: some Lightweight barrels apparently suffered from a porous oilway. I don't know how this manifests itself, but I guess it would mean a lack of pressure to the head. I only know this because the oilway on one of my barrels has been sleeved to address this problem. Just a thought...

PS: if there's plenty of oil up there, I wouldn't worry too much. The oil feed metering screw and jets were deleted on later models, so I would assume there's no harm done as long as everything is oiled generally. By contrast, Moto Morini v-twins have NO oil feed to the heads at all: they just rely on the oil mist. They last for ages...

and here is an image from the quiz of just such a barrel
I believe it manifested itself by oil leaking out of the side of the barrel but only hearsay not experience.

Thank you for this thought.
I've now located a bolt , so that'll be 1 thing less.
It's frustrating when things aren't as they should be !
I'm wondering if the lack of "squeeze" of the head gasket around the oil hole caused by no bolt may allow the oil coming up the oilway to dissipate back down the pushrod tunnel.
It'll be interesting for sure to see if taking the bolt down , pushes the oil up the top