Bike idles well and runs okay at small throttle openings, but still misses and farts about when I wind it on. Plugs are black and sooty (dry soot) so I changed them for a fresh set of B7ES. Made no difference. JB Nicholson (Modern Motorcycle Mechanics) says mid-range hesitation is caused by leanness, so one should richen by raising jet needle (i.e. place clip in the bottom-most of the three grooves) until any hesitation disappears. I did, and things got even worse.
I also found that the RH carb nuts were backed off too much. I could grab the carb and move it round on the stub, so probably have a manifold leak. I tightened the nuts to the point where the slide jams, then backed it off until it freed again. This seems to have fixed any leak.
I carefully examined the old worn-out carbs that were on the bike when I bought it. The jet needles on these are fully lowered, i.e. the clip is in the top groove on the needle! Yet I have just junked the standard airboxes in favour of a K&N type, so surely must need to richen the mixture, not lean it out!
I took the bike up the Tamavua ridge, missing and carrying-on. By the roadside I removed the slides and moved the clips to the top groove. Then I rode on to Sawani. The difference is MAGICAL! Not a single cough or splutter, pulls strongly all the way. Took it up to 85mph on the Sawani-Nausori straights – "goes rool good!" , as an Aussie would say.
Back in town at the lights, it wouldn’t idle and only ran on one pot. I suspect one float needle may be sticking and flooding the carb intermittently.
Looks like the mid-range carb problem is now sorted.
Next – install oil filter and oil cooler kits, and clean/bleed brakes.
