does a timing advance make a noticeable difference with the ms 290 ,310, or 390s. Just wondering if it’s worth my time doing it to my 290 or 390. Both are muffler modded. The 390 has a pop up piston in it.
The key is made to the flywheel on the 1127 series saws no such thing as an offset key for one of these you are correct however in that the taper holds the flywheel stationary on the shaft.When working with tapered shafts its actually the mating tapers that holds the shaft in place. The key is insurance the the two mating parts won’t miss aline. I would lap the shafts together first. Then clean and assemble with the offset key.
On the Swedish dirtbikes there is no keyway on the tapered primary output shaft. The correct torque on this taper holds it.
Have you looked at the fly wheel in your 350? It’s very similar to what this gentleman has. The key is cast along with the fly wheel at the same time. It’s part of the fly wheel. File part of it away, assemble it, and tighten the nutHelp me understand there are different ways to advance the timing. Are you talking about filing the key way slot in the flywheel?