750ss - M750 engine whats the difference
 

I now have a 1991 750ss and a 2000 M750 both carbed 5 speed wet clutch models both have termis ,the 750ss seems more tractable and smoother and seems like a higher tickover , both are set up on same carbtune unit for balance etc so I wondered if the 1991 model might have bigger valves or something seems mainjets are slightly larger too both bike run great but different character of engine ...YES I know the chassis and ergonomics are not the same but the engines seem so different? curious.

I wouldn't have thought tere would be that much difference, maybe a few changes to allow for emission changes over the years and possibly slightly different compression as fuel is not quite what it was.
i think the heads are slighty different as the 2000 M750 ones are as I understand it the same as those fitted to the 750SSie
The primary drives as well as the final drives are different so that will also make it feel different.

Yes The final drive and primary ratios probably have some thing to do with it, my M750 has a stage 2 tune with Dynojetted carbs K&N airbox mods ,termis and reworked valves and goes so well many people think its a 900 but the 750ss which appears standard apart from the termis revs more freely and smoothly. maybe its the aerodynamics of having the fairing.