Andy wrote:Lots, and I mean lots of small changes between 1987 (MC16) and 1988 (MC18 Mk1) took the power from 45hp to 60hp.

It's not quite as simple as just bolting the later parts on, but it can be done, although you'll need to spend a lot of time setting it up correctly.

First off; don't bother with high compression. NSRs really don't like it. Yes, there is a very small increase in compression year-on-year, but they are very small increases. In my experience it's a bad idea trying to run high compression.

As Jasper already pointed out, the MC16 runs 28mm carbs whereas all the other models run 32mm. The MC16 doesn't run a powerjet or any air correction. Simply bolting on MC18/21 carbs will take a lot of setup to get right. Just FYI, the MC16 TT-F3 is rated at 68PS with 28mm carbs... they're not actually as bad as you'd think. To really make the most of the MC18/21 carbs you also need the corresponding ignition & air correction. A lot of hassle!

MC16 expansion chambers are a bit crap, so you could consider some R2J pipes/silencers, and the crankcases can be improved greatly. You can see how if you get hold of some MC18/MC21 cases. The MC16 exhaust ports are very small, but be careful modifying them too much. MC18 cylinders can be used, but you need to be very careful setting the RC Valve up. Any gains from the MC18 porting are immediately negated (or worse!) by bad RC Valve operation.

The best thing, in my opinion, is to optimise the MC16 stuff; especially the crankcases.