Some models the nuts holding the sprocket on are on captive bolts, not studs. They look similar to what cars have for the wheel nuts. Are you sure they are studs ? If they are the captive bolts they might just knock out with a hammer and the new ones get drawn back in with a nut and some improvised spacer.

The studs in the sprocket hub are stripped out. The hub is probably walloed out also. Probably will have to have a new sprocket hub. I doubt I have the ability nor the tools needed for this job. Thanks for all suggestions/opinions! 20240225_155255.mp4 20240225_155255.mp4 20240225_155255.mp4 20240225_155255.mp4

You'll get the hang of it. It's handy for posting just a few pages.. wiring diagrams etc. I looked in manuals I have and it seems to be fairly common build. All you'd need to do to get the old bolts out would be undo the nut that holds the sprocket hub on and slide the hub along a bit. If it's seized on the splines it might be a bit trickier. Then I'd try wedging it first off, and if that didn't work I'd pull the wheel hub etc and use metre long threaded rods to improvise a puller to pull the hub off. I always have two in my workshop so I'd get a third and put one through each bolt hole and use some old steel plate or puller hub I'd have. You might be able to use the sprocket with something behind it against the axle so the sprocket doesn't bend. Threaded rod from the engineering supply shop's fairly cheap and handy to have.

I don't know about anyone else but I haven't been able to see your videos or that picture P52.. It might be that you need to save them as some other file type before uploading them.. Doh.. Tried again and the photo did open.. As you were...

Yeah not sure why but they are always stripped out, remove the wheel , remove the 3 bolts holding on the sprocket protector, 3 more nuts hold the sprocket on the hub, wet them good with PB blaster and hold the back side with vice grips or something similar to get the nut off then you can better evaluate your hub, im sure it can be saved .

How were the valves, guides and seats when doing the top end? Did you adjust the valve lash to spec?

So it had this same problem before you replaced the carb twice, and did the head up ? Initial impression, since it's popping out the inlet and exhaust, would be that your ignition is failing.. It might be that the ignition timing is going erratic.. I think I'd put a timing light on it and watch the timing and that the spark doesn't fail as I rev it up. Could be the cdi or a wiring fault. You could also check the charging system is regulating as it should.

I would check the timing to make sure nothing moved while replacing the cylinder.