Cafe Racer Forum banner
1 - 1 of 10 Posts

· Premium Member
7,411 Posts
I agree with Rob. Mostly clutch dust and very fine aluminum.

I use either Mobile 1 20-50w or Royal Purple Racing 41.

The Mobile 1 is pretty dark to start with in the thicker grades. The Royal Purple is of course Purple so you can't tell much there. When I drain the oil I get what look like swirls of silvery stuff in the oil, extremely fine, looks almost like an oil slick on top of the oil. I see very little if any solid matter in the oil after I strain it. I strain every oil change through a fine filter to look for debri.

Using dyno oil you WILL burn it somewhat in these engine during a race. Running these things for ten laps at 12k rpm gets them very warm, it will "roast" dyno oil somewhat. Mine comes back to the pits with the entire head spit spizzling hot..literally. I would say that synthetic is a must on these engines if you expect to keep the valve train alive. The crank and tranny are probably not an issue. Running Royal Purple I've noticed the oil supply side of the head is noticably cooler than the down stream end of the head.

The only thing I really look for is flakes of chrome (rocker pads) or pieces of rubber (cam chain tensioner). Mary's mostly stock engine came back from it's first race with not the smallest bit of garbage in the oil. I very, very thoroughly clean and engine when I put it together so I know that anything in there came after, not before. You will notice after some time on the track a fine black silt that gathers in areas of crankcase, that's probably the clutch material. I've never seen a honda engine that doesn't produce this stuff.
1 - 1 of 10 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.