Hi Alex,

I use my 28 as a road bike. These are my observations.

Many run RVF400 forks. Others have RS250 NX5 forks but they will cost you a pretty penny. Tyga do triples to suit both. They also do triples to suit the stock forks. I rebuilt my stock forks and run Tyga billet triples and to be honest I'm very happy with them. I really don't see any need to go to USD forks at all. You also lose steering lock. Rear shock is another story. I've been thinking about getting a fully adjustable Ohlins unit which is now available for the 21 and 28.

Many run the head from the rear cylinder on the front cylinder. You need a different radiator hose and an expensive stubby spark plug to clear the radiator. Others here may correct me if I'm wrong but you don't gain a lot of HP from it. For a road bike, not at all necessary unless you are chasing HP.

From my perspective best and cheapest gains performance-wise are wire splice (to delimit the ignition), decent exhaust (although I've heard told the 21 exhaust is pretty good; just heavy), make sure the engine is in good condition, airbox mods and good power valve cleaning/adjustment. All cheap with a 21 and you will end up with 60 plus HP with a virtually stock bike for no more effort than a re-jet.

With my 28, as well as the rather expensive HRC ignition that is needed for that model to delimit the ignition, I also installed billet exhaust manifolds, performance reed block and had some mild porting done. It's putting out a reliable low 60s HP running slightly rich. Radial front brake master cylinder (from a CBR1000RR as it accepts the same brake light switch) and braided brake lines are also a good upgrade. From there it's more and more money to chase less and less HP gains with less and less long term reliability.

Cheers
Jim