The #32.5 pilot jet in conjunction with the idle screw and air screw controls the idle speed and AFR up to 1/4 throttle where the needle takes over.
The needle and needle jet plays a major part on the AFR from 1/4 to 3/4 throttle, at 3/4 throttle the main jet comes into the scene up to WOT.
Raising the needle clip weakens out the mix, 1/4 to 3/4 throttle, while lowering the clip richens.
The float must be set correctly.
Float level should 20 to 21.5mm on a stock carby.
Then the idle must be set.
Idle adjusting.
Start with air screw 1.5 turns out.
Set idle screw so that it has some sort of idle.
Warm up motor and then set idle screw for a fast idle.
Adjust air screw either way to get the fastest idle.
Adjust air screw a little at a time leaving 10 secs to allow the motor to respond.
Re adjust idle screw for desired idle .
Needle on middle clip, #290 main and plug chop to confirm.
Plug chop.
Warm up motor to operating temp.
Fit new B8ES plug, ride through the gears and hold WOT in 5th or 6th gear for 10 seconds, or as long as you can safely.
Switch off the motor and pull in the clutch, roll to a stop.
Take the plug out and replace the old one for the ride home.
Carefully cut the threaded end off the plug to expose the insulator.
There should be a smoke ring of a cardboard or biscuit colour around the insulator.
If it is non existant or a very light colour, you are lean and require a larger main jet.
If it is a lot darker you are rich and may go down a size in main.
I prefer to run a little on the darker side, I may loose a little power but it is worth it for the peace of mind that I won't need a rebuild so soon.
Heres one posted by Awk a while ago, this is a good to go plug.
This one is a little rich, but I would run it, I like to be on the safe side.
