Arrrggghhhh. Aylesbury! Glad that I'm away from that place!!!! 23 years was more than enough.

Actually from Wendover, but close enough.

Back on track, I would say that it'll be best to get your 18 running right as it is before you start modifying it.

For some reason the 18's seem to be more critical than 21's and 28's when setting up the RC valves. In the past I've had a couple of static fiddles, with no great results, then just blasted it up the road, held it nailed in sya 4th gear and at max rpm hit the kill switch, just like a plug chop, only to find that the RC valves were a couple of degrees out. Dialled 'em in and was ready to rock.

Also, have a good look at your air filter, and get a new one if necessary. try giving it a wash in some mild detergent and warm water. if it falls to pieces then you're probably due a new one anyway. If it cleans up ok, don't forget to oil it when you put it back. MX shops are the best place to get filter oil as they seem to get through tims of the stuff.

You're carbs might also be in need of some TLC. this would be a good thing to look at anyway, whenever you buy a used bike, especially a used NSR. make sure the jetting is stock (if all other parts are stock) and squeaky clean.

With all things being in good nick, the 18 should be a real hooner, even in stock trim. Honda did a really good job of making every new model just that little bit slower. When we've restored 18's from the dead, we've always joked about the 'classic' styling, but never about the stock engine.