Domi 88 cylinder head oil return

Should not be there. Can only assume that this is a mod to encourage more oil to flow down to cam followers. If the inlet valves have seals may be a good idea, perhaps in your motor hardly any oil gets up there anyway?, like mine used to be.

Previously Graham Martin wrote:

Previously robert_tuck wrote:

Should not be there. Can only assume that this is a mod to encourage more oil to flow down to cam followers. If the inlet valves have seals may be a good idea, perhaps in your motor hardly any oil gets up there anyway?, like mine used to be.

Thanks Robert those are my thoughts too. My problem has been oil forcing it's way through the exhaust ports and this might be the reason. If I remove the plug and I've checked the chamfer on the tappets are facing forward, I just might have solved it. Fingers crossed.

My 1957 88 cylinder head has this hole which I understood to be the drain for those valves the other valves drain thru the hole in barrel to crankcase? I have excess oiling to the valve gear even with the hole clear.

Oil in the exhaust ports is likely to come from guides not sealed to head . I would tap them part out ,seal round with RTV and tap back in. Should be able to see oil track from guide in the ex port.

Hello, This oil way is NOT a mod has you so call it is a drain hole and should never be blocked up!!! , and you should NEVER EVER KNOCK OUT VALVE GUIDES COLD HAS they are An INERFERANCEFIT and a good Gas or electric oven shouldget them hot and they should fall out please use suitable glovesto handle the hot cylinder head and a good size wooden chopping block or make one from a 9 inch by 3 planks of wood and good peace of planed pine or hard wood are both good for this job also you can make a nice wooden engine stand has well most usefulwhen rebuilding a Nortonengine singles or twins and you can make a wooden engine fork this goesover the mouth of the crankcases and is marked out to fit over the barrel studs this stop the movement of connecting rods and pistons and most useful when fitting the barrels use a nice peace of ply for this sanded down and primed with MDFsealer so no splinters come off

to save you arms and money plan ahead before any engine rebuild or strip downs and get your information right for your model do your home work

have a lot of nice rides out and fun in the sun yours anna j

Anna, you really must think before posting. I never suggested valves guides should be removed COLD. I never said the oilway was a mod. The plug is. I know you have good information to impart but it does not help if you ramble on.

Anna, you really must think before posting. I never suggested valves guides should be removed COLD. I never said the oilway was a mod. The plug is. I know you have good information to impart but it does not help if you ramble on.

Just to round this off:

The obstruction would not move with air so I filled the hole with oil, used the shank of a drill as a piston and it flew out no trouble. The obstruction was of a similar size to a roller from a bearing but not as hard. There is no way that such an object could have got there without being carefully inserted so either the previous owner had upset a mechanic or someone had a very odd theory on oil supply!

When I acquired the bike the engine was encrusted with oil & muck and this little plug probably explained why and suggests the previous owner was riding it in this condition. As they say there's nothing stranger than folk!