Poor head oiling 99

For the Jubilee model the factory made a special oil tank return union adaptor and the tank end of this had approximately the same size of hole as the transverse hole through which the oil passed up the rocker feed pipe. Both of these holes should be about 7/64" or 2.78mm in diameter. You can restrict an existing oil tank adaptor by tapping the tank end for a small grub screw drilled 2.78mm to suit.

A quick fix can sometimes be made by wrapping a short length of split fuel tubing across the outlet hole inside the oil tank.

However......if the oil intended for the rockers is struggling to climb up the feed pipe then it is generally a sign of a worn-out oil pump. Especially the scavenge gears which spend much of their running time sucking air and rubbish from the sump.

Get your pump serviced first before messing about with restrictors.

Previously robert_tuck wrote:

Not enough oil is getting up to the head.I intend to reduce the return outlet in the tank. Does anyone know the bore size of the Jubilee fitting that is the normal fix for this.?

Hi Robert.Don't know the size of the orifice off hand but if you buy the part it won't matter, just fit it. May I suggest theproceedure I took to sort out the same problem.On my bike the original thin bore copper pipe that fed oil to the valve gear has been removed apart from a 3 inch stub. It has been replaced by a rubber pipe. To check oil flow to the head I remove the rubber pipe and connect a five foot length of narrow bore transparent plastic pipe to the stub the other end I connect, open ended, by a bit of string to the garage rafters. When the engine is ticking over the oil in the plastic tube quickly rose to about 4 foot above the oil tank. If it does you should have sufficient pressure to get oil to the head. Don't rev up or the oil will shoot out of the end of the pipe and give you a shower.

If you are getting a good flow of oil I would suggest you replace your oil pipe, first checking it to see there is no blockage in the pipes or the two unions in the head. The union bolts carrying the oil into the head should have punch mark on the top to show when the hole in the bolt aligns with the oil pipes to give least restrictionto oil flow. By the way, if when you remove the union bolts from the head you squirt some oil into the holes you should see this trickling out onto both rocker shafts Naturally, remove covers first of all. You can also check the ends of the rocker shaftsare not blocking the outlet holes.

Alternatively, just slacken of the rocker shaftcover screws a couple of turns, start the engine and you should see oil leeking out. If it does the problem is in the head, if not it's before. Someone has already suggested temporarily blocking the hole in the return pipe inside the oil tank. If you do, you should see an increase in oil flow to the head. All the best. Peter M.