Motorcycle Repair: CT 125 1981, xl models, point gap

Question
Gday Bill, I bought a CT 125 and wanted to know what the point settings are for this bike? Can I adjust the timing using a timing light and what is the proceess for setting the timing.
Thanks

Answer
Gday, Greg.... CT125s were 1 year only bikes in the US, but apparently used a bit more Down Under, right? Sure it is a 1981 model? They were only sold in 1977 over here. Most 80s 125s had CDI ignitions for CB/XL models. Anyway, you mentioned points, so we'll go with that!

Point settings are .014" give or take a thou. .3-4mm for you over there in metric land.

First, remove the point plate and check the mechanical spark advancer for proper function. They often seize up and that really messes up the ignition timing, either at idle or high speed. If you take the point cam off the advancer base, MARK it first. Otherwise, 50-50 chance of putting it back right again and if you miss, it won't run!

Once the advancer assy is back on the end of the camshaft, grab the end of the advancer (before you put cam lube on the point cam) and try to move the camshaft laterally, just to be sure that no cam bearing damage is present to throw off the point gap settings. That was a real problem with the early 1-piece cylinder heads from 1970-75. Now, you can put a dab of point grease on the point cam and/or drip a drop of motor oil on the felt, if it is still there.

Once the point faces are all cleaned up, turn the motor over with the crankshaft bolt and watch for the points to open to the highest gap, measure and adjust down to within specs. Once the gap is set, then move the point plate until the points just start to open when the F mark on the flywheel is aligned with the pointer. You can use a 6 or 12v test light, depending on your systems battery voltage to monitor the open/close events. No need to check it when running. Rotor spins in the crankcase full of oil, so it will get tossed all over the place anyway. Static timing should be more than sufficient. If installing new points, set them a little on the wide end of the specs, as the rubbing block will wear down in the first 100 miles/km and the timing will retard, as a result. So, set the points at .4mm and have them open a bit ahead of the F mark, if they are NEW points only. Otherwise, set them as suggested above, right on the F mark.

Okay, got it?

Pretty simple stuff on a pretty simple machine. Hope this fully answers your question...

Bill Silver