Giff wrote:Turbocharging is impractical and particularly unrealistic on a little V4.
Cost wise, turbo, which you'd have to mount around the rear shock, sealed airbox, sorting the fuelling and rebuilding the engine to cope with the power.
The GSXRs you have linked to are much easier to do that type of conversion because of the type of engine (IL4) and sorting the fuelling (already fuel injected). Parts are also readily available off the shelf.
I have some experience of forced induction, if you honestly think you can stick a turbo on a little V4 then do it and post up the results.

Err that bike was an 86 GSX1100.. they use tiny 32mm carbs :)
The 89 K model is what you want... they also have mikuni carbs but with werid shaped slides.. engines are rock solid though, they tune and turbo well without any strenthening required.. i'm sure they were built out of granite or something :D
As I said in my previous post the exhuast design of the V4 makes things more interesting, but not impossible.
The design of the NC21 and NC24 collector box is quite interesting.
I just like the idea as its novel and different and presents some engineering challenges while keeping the engine the same.