Honda cb250 k4 cam shaft

[bumble]

 
I have a 1972 cb250 k4 which keeps on siezing on the end bearing on the cam shaft on the left hand side, I have heard that early k4's had this problem and it was something to do with a gasket in the bottom end restricting the oil supply to the top end. Has anybody else had this problem, and got any suggestions as to the cause or a cure?

[Grizzly]

Hi Bumble

I have had similar problems with a CD 175. I am not familiar with the 250's, so this info may or may not be relevant.

 
Behind the o/s engine cover is a gauze screen that can get blocked and stop oil supply to the cam bearing.

Also check that the centrifugal oil filter is clean.



Grizzly