Jerry and Anthony:

The whole length of time I ran alky motors from the late 60's to 2003 or so, timing was set staticly for as much as the engine would stand up to about 6-7 thousand or so, because if it was set any higher, at the higher RPM past that, burned or stuck pistons were sure to result. When the CD ignitions came out, even the early Phelan self excited type used on the Konigs, they supposedly had electronic means in the "porkchops" that the flywheel passed by so as to retard the spark at higher RPM electronically. In the mid 90's I had a 125 made from Honda and Yamaha road race bike cylinders, and we used an MSD ignition on it that came with small plug in modules that allowed retarding the spark at higher RPM to keep from burning/sticking. These modules allowed different degrees of retard at different RPM's, and worked very well, but for some reason MSD went away from that type system, and then you had small switches on the box itself that could be arranged in different sequences to do the same thing. If you did not use that those type devices after they became available and tried to run the same static timing (high)you set for best acceleration all the way to top RPM, without some way to retard it past 6-7 K RPM you would be replacing pistons very regularly. Most of the explanations to this point I have read on this thread say basically the same thing, more advance at lower RPM for acceleration, but it you run it high pushing the envelope too far up the RPM range without some way to retard it, either mechanically or electronically, it gets costly very quick My experience was the same as Fred's, and I am not near as smart, so I think he knows of what he speaks, cause I had those boxes of burnt pistons also, as did others that tried to push the envelope. Of course if you want to run up front, that is what you have to do.

There are several manufacturers of ignitions out there that have these features. Whether they could be adapted to work on a Yamaha of the type described is another matter, although where there is a will, there is a way most of the time, with enough money.