This is what the 90 degree fitting and the drilled screw look like.

(NOTE:  They have not been cleaned up and there is metal chips on them).

So dumping oil to control pressure with a main jet , in a more useful area , cool. These engines attracted me for several reasons , starter , 650 single and engine is self contained ( no external oil lines ). You’re giving it more places for a leak/failure. I think a small braided line with fittings might be less prone to failure over a rubber hose with clamps and would look far better too. Your bike looks great ! My bike could stand to have an oil cooler for doing 90 on those 105* days , but not willing to risk it leaking. My BSAs all have hoses & clamps & leaks ! All my Yamaha SR 500s had upgraded double top end braided lines to the rocker shafts. I’d hate to hear about you having a problem on the road , oil leaks suck , just before it hits the rear tire. Ride Safe.

Well I got it figured out....I think!

The clutch cover oil feed will be this:

I had a piece of 1/4" stainless rod, and I made a 1/8" hose barb with a 6mmx1.0 thread on the other end.

I then drilled the head and tapped it for the new hose nipple.

This is a view from the underside of the cylinder head cover.

This was a bit scary to do.....as I did not want to drill through any thin areas that would not hold the threads adequately - or drill through any oil passages!!!!!

Ruttly wrote on Yesterday at 20:23:51:


The oil in the head cover that flows to the left front of the head goes down a drain along the head stud - it oils the left main bearing.  Oil also can just fall down the cam chain housing.  I can't see any downside to adding some extra oil up there......you have to remember the amount of oil flowing is coming out of a hole in the jet that is only O.052" in diameter!

I am likely going to make the rubber oil tube up to the head a little long, and temporarily put in a "TEE" and tap in a pressure gauge to see if there is any measurable pressure in that new bypass line.  First the oil passes through the small 0.052" hole that is the desired "limiter" on the amount of flow.  The oil than passes into the 90 degree fitting that has a 0.128" entry hole and a 0.86" hole in the nipple.  The rubber tubing has a 0.125" ID, and the new nipple I made has a 0.093" entry size and a 0.111" exit hole inside the head cover.  The exit nipple on the 90 fitting is the smallest diameter after the restrictive jet - and it has an area 2.73 times the area of the jet!  Any pressure in the rubber hose and fittings will likely be minimal.

The goal of the overdrive oil gears is to bump up the oil pressure and flow at lower engine rpm - at idle DragBikeMike measured very low pressure with the stock oil pump...and this is likely a contributing factor to the large number of failed rockers and cam lobes (made worse when folks lower the idle speed to get a cool thumper sound).

My goal for the size of the orifice is this from DragBikeMike:   So, if you want 10 psi at the cylinder head adjust your bleed orifice to achieve 17 psi at the filter housing.  That would be at 4000 rpm and oil at normal operating temp (200 F).  I will adjust the size of the orifice accordingly.

   

I don't often ride in areas with lot so traffic or traffic lights that would lead to low oil pressure often - I suspect my bike would have done just fine without the oil pump mod....but obviously I am someone who likes to tinker and build stuff!!!!