Good to see Paul on the new Forum. What that man doesn't know about the NF.....?
Having bought Paul's bike, I can confirm that once I'd sorted out the jetting, fitted a K&N filter and a free flowing exhaust (it's certainly not a silencer) it goes like the clappers. Running on the original 34 tooth rear sprocket, I was clocked at 90 mph by a friend following on a modern Triumph. It blew a head gasket shortly after!
By doing plug chops, I ended up with a 140 main jet, which runs slightly lean. One higher may be better, but haven't got one to try. I had a few blown head gaskets, but now it's torqued to 40 lbs, no problems. While I had the head off on first inspection, I took 2mm off the overall diameter of the push rods (drumsticks) and matched in the tapers, also grinding down the steel cups to match, while narrowing the lock nuts on the rockers. With the lighter valves, the reciprocating weight of the valve train has been greatly reduced, allowing a safer upper rev limit. I've no idea what the engine was revving to, when I was clocked at 90, but it was high.
With twin plugs, the timing can be retarded due to the shorter time needed to burn the fuel. I read that Porsche engines were retarded by 10 degrees, when switched to twin plugs, so aimed towards that. On the NF, this equates to zero static timing. At this, my NF really barks, being extremely loud. Advanced to 4 degrees static, seems to give a softer engine at tick over. There is a definite power band, when the engine changes rapidly from plodder to racer. To harness the extra power (??) I fitted the shiny new 31 tooth rear sprocket in the spares kit, that Paul included with the bike. The sprocket transformed the bike, giving a usable first gear and motorway cruising speed of over 70 mph, with an overtaking speed of 85 mph readily on tap. I have no desire to test the flat out speed on this gearing.
My early intention was to skim 10lb off the flywheel, but I like the easy one swing start and slow tick over pace of the bike, feeling that I have the best of both worlds at the moment. Once the weight is taken off, it can't be put back on.
Did you get a measurement of the compression ratio Paul?