Blanking the PJ's can make setup on a race bike easier, as you can just concentrate on the mains, but on a road bike they generally tend to give you a slight margin of saftey. In very basic terms, the higher the RPM, the more fuel drawn through the PJ's (and hence a richer mixture). High RPM and weak is BAD... high RPM and rich is not so bad - you just lose a little power!
If you haven't modified the airbox, then I expect 138 will be too rich. If you have modified the airbox, I wouldn't be surprised if 138 was still too rich, but you will never get me quoting jet sizes.
No idea about the CBR wheel. Anything can be made to fit (probably better off looking for an NC30 front wheel), but why bother? In my experience an NSR with a 120 front tyre steers like a pig. The stock tyre sizes work the best.
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Andy.
NSR-WORLD.COM
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