This weekend I finished up the SL100, at least the first phase. My intention has been to get the bike running properly in stock form, so my daughter could ride and enjoy it before boot camp, and then later as time allows will modify and improve for when she rides it in vintage mx.
After finishing the clutch, I went back to the carb. The new needle and orifice needed installed, so once again I took the carb apart and with some gentle persuasion had the orifice out. One look under the magnifying glass told me the whole story. No wonder I could not get this thing to run right! The orifice was rough, worn and egg shaped, the needle somewhat less worn but still showing signs of a long hard life. Put in the new pieces and fired it up. It was so lean now it would hardly run. I tried raising the needle one notch which helped a little, but it needed more. When I originally rebuilt the carb I'd put in a 105 jet that in some books is shown as the stock size, but in others it shows a 110. I had a new 110 so put that in and it really started to come around. A few finer adjustments and at last a decent running 40 year old baby thumper!
The old worn parts, towards the bottom of the orifice you can see that it is egg shaped;
First ride on her "new" bike;
That does it for now. Back to the vintage twins!