Oily XR Rocker Box

Actually my bike is an XLR 250, 1992. This is a Japanese import, basically a detuned XR
250.

I need help on two items:

There was an oil weep from the left front cylinder-barrel joint. Took off rocker box and
the left front valve "well" was swimming in oil, flush to the level of the rocker box joint.
The right well drains into the cam chain tunnel and was "dry". I would have thought the
left front well would have drainage flows cast into the head. It seems not. This explains
the leak/weep at the cylinder head directly under this valve well. It explains why one
port of the exhaust, adjacent to the left well, is black and oiler than the right ( cam
chain side)

My question is: Is this oil buildup normal on XR 250's? If not, why and what remedies?

My second problem is the cam chain. How can you tell if it is worn when still on the
bike? Should you be able to lift it AT ALL clear of the teeth of the cam-sprocket? Can
you test it for looseness in place? If so, how. I am getting a weird slapping-pinging noise
at about 25% revs when the bike is pulling (opened up off the cam, so to speak) hard.
It sounds like its from under the fuel tank.

Thanks for help. I am hundreds of miles from a dealer.

email: pamoja1@wananchi.com

Cheers

Peter in Africa

Oily etc

Yes, it's am RFVC, 99% identical to an XR 250.

It is hardly smoking. It is only rich and a little oily in the left exhaust port. It is rather leaking/weeping oil at places noted, due to oil build up in the left front valve well/seat spring area. I am surprised there are no channels in the left front vale well of the cyl head to drain oil back.the job done by the cam chain hole on the right side.