The RRj is the 88 model and the rrk is 89. The air boxes do not interchange and the gearing is different. The 88 model is the full power and the rrk is restricted to 112mph though they are usually desrestricted and its fairly cheap to do that.
The 23's have weak clutches and are taller than the 29 as they have an 18" rear wheel which restricts tyre choice though you can still use the fantastic 090.
The 29 is lower as it has a 17" rear wheel which gives a wider tyre choice. Its arguably not as good quality as the 23. The 29's weak point is 2nd gear. You need to red line it a few times and make sure it doesnt jump out of 2nd gear

FYI, here's the NC29 link: http://www.vsource.org/VFR-RVF_files/Bcbr400rr-mi.htm" onclick="window.open(this.href);return false;

Ciao,

The 23's have weak clutches and are taller than the 29 as they have an 18" rear wheel which restricts tyre choice though you can still use the fantastic 090.

How difficult is it to fit NC29 wheels onto a 23?

How difficult is it to fit NC29 wheels onto a 23?

not as hard as you might think, i did have the 17" on my nc23 rrk but i switched back to the 18" cause i didnt like the way it handled, and plus i love my bt 090 tyres lol

Hmmm...might be worth considering. I may be in the market for another CBR sometime. Except for the tyre sizes, are the only other changes between the 23 & 29 skin deep?

I realise the 29's a bit of an overhaul over the 23 - but can you really feel the differences one has? The 29s seem to fetch more money...