It's now fitted with different exhaust manifolds and modified RS pipes.
The biggest issue was chasing the jetting. As the morning warmed up so I kept having to change the brass and never really got to the perfect setting.
Having said that, it now makes an NF5 feel very lethargic and will likely pass the NX5 down the chute. But........unfortunately for 300 haters like Granty, it still has dollops of midrange, so will out grunt the NX everywhere. If he wasn't such a lazy git and paid attention to my text messages at 7am this morning he could have come up for a ride. Oh well, his loss. He still hasn't answered so more than likely still kipping.
As for running NX5 parts on an NSR, I think you're not gonna have much luck without easy access to a fully equipped machine shop.
For the record, I'm trying this set up on two types of bottom end.
first we have my old NSR300 bottom end which is basically a well modified NSR, including stock (albeit perfectly trued up) crank, and VHM heads at 14.2cc for pump fuel.
Then there's this fire breather, which is a '92 NF5 bottom end. I epoxied and cut the cases for flow. Pistons Wiseco. VHM heads at 13.5cc burning avgas 100LL, PWK 39's (maybe too big, must try smaller) and an adjustable CDI. Pipes, as I said, started life as RS250 NF5 but mow modified the headers a touch. Manifolds are similar to my special NSR250 manifolds, which Brother Stephen has shown to give more mojo on his brake, in that they're matched to the port shape.
It suffers a bit from vibration as the engine's solidly mounted, just as it is in the NF, but hey, what's a few vibes among friends.
Anyway, I'm now very happy with this project, and will finally be able to sort out the people I've been promising results to.
To be honest I'm not sure where to go next. I have a 3MA on the bench which is great now that I've sorted the carburation out, but I think it needs surgery.
Then there's my Honda LS125. I'm thinking reverse the cylinder, out the arse pipe, big carb and and and.......