Originally Posted by plumber mike
It's now sporting an 81 XR200 front end.
My bikes engine number starts with SL too. I wonder what kind of frankenhonda I have?
If the engine number starts with "SL" then it is a 1972-73 K0 engine, it'll have no fins on the timing chain side of the cylinder head. 1975s on have small cooling fins there. Top end gaskets (and bolt pattern) are unique to the 72-73 engines, so good bit to know if you ever plan on tearing down the top end, especially if the "bike" is a "75" ...ish.