Hitchcocks Forum

..lots of cork inside the rocker assy.. in both..
How does it get thjere and where can it be from?
I am worried a bit (in the process of rebuilding the engine) that cork particles might be stuck in the oilcanal of the crankshaft..

I think you have to consider two possible answers. First, and worst, this could be cork fragments from the cork seal on the quill of the big end oil feed. That wouldn’t be good news, mainly, as you say, because particles could have found their way into the oilway drillings to the big end.

Second, you may have cork gaskets that have deteriorated and broken up. But I think this is unlikely.

If you are rebuilding the engine you are presumably stripping and rebuilding the crank?

For the cork fragments to have made their way up to the rockers, it sounds like they have already been pumped through the big end and into the sump before being picked up by the scavenge oil pump which feeds the rockers. The gauze strainer on the scavenge-side drain plug should have picked out any larger pieces but will still let smaller stuff through.

To avoid this happening in future, the cork oil seal in the worm nut can be replaced with a neoprene version, part number 16704A, or you can fit a worm nut which already has a neoprene seal bonded in, part number 144452.

A.

Hi, how do you know its cork? As stated below if quill seal it would have to get past bigend, sump strainer and past rocker. If large enough to identify most likely a cork rocker cover gasket. I cant from memory remember any cork items beyond the quill and clutch plates being used. Vince

The only way cork could get into and through the big end would be if the cork seal [if you have one] were damaged when fitting the timing cover and / or quill bolt into it, and not due to normal running of the engine. As Adrian states, any 'cork' you have found in the rockers has already got past the big end and one gauze strainer, unless it has come from something else, but normally there wouldn't be anything. I have seen cork rockerbox gaskets before now, perhaps your machine has had some at some stage? I have had less trouble from cork seals in the end of the crank than either the push in or bonded in rubber seals, to be fair and I have just used two in my last two rebuilds.

The 'quill seal installed was indeed cork, but this one was not so damaged it could provide for all the cork(!) found on the rockers..
I've blown air through the oil duct and it is free.
There is-now- no other geasket of cork in the engine, so i am puzzled.. trying to comfort myself that if it gave crankshaft problems, it would have run into destruction already.

I read somewhere the neoprene quill seal was not so great?

Thing is indeed, it is the only way it gets there through the oil ducts?
I will make autopsy of the old oil filter and report here..

Nevertheless first 1000km's are eh.. what's the word?

Pics..
It feels and looks exactly like kork, but there's more
Could not find any on/in the oil filter.

What is this?
Beside some strange gasket(?) remnants?
Seeds? Really??

Those do look like apple seeds.

Also by far the roughest looking timing chest cover casting I've seen.

The cork-looking pieces look far too big to have passed through the filter screen on the crankcase drain bolt. I presume you have removed this and checked the filter. There is no real way for the seed material to get from the timing chest to the rockers because it would have to pass through two gauze screens and the oil filter.

The only conclusion I can come to is that foreign material has been deliberately introduced into your engine at some point. Either by kids messing about, someone with a grudge against a previous owner or -as an outside chance because you do hear of some odd things- some weird Indian superstition about magic properties of some sort of fruit.

This engine does not have a filter at any of the drain plugs..? I took the engine cases apart for rebuilt and there was no filter? Where should it be?

And the casting.. The bike was imported by a private person and seemen an inland version (single leading front brake, 17T sprocket, iron layshaft bushes)