250 cdi jetting

[27maverick]

My 86af motor has the 250 cdi fly wheel. My carb is 41 from john at sudco. The bike starts with 3 to 5 kicks. Idles good fuel screw 2 turns out the pilot is a 60 main 195 , I have 4 needles from john , The richest needle is the one installed. The bike would always rattle at about 75% throttle, just before going completly on the main. But the plug color would be more black than brown. With the richest needle now that rattle is gone at 75% but the bottom to about 75% it will load up and really never clean out until super hot, and then it still loaded up. I went to a 55 pilot and now it cuts in and out like it's running out of fuel. I can try a 58 pilot but it's hard to believe such a small change is going to help this issue. The bike runs good on the main. The only needle that gets rid of the rattle is the one in it. but now it runs like shit in the low to mid. I'm thinhing the 250 ignition has something to do with this. The more rpms the more fuel and the transition from needle to the main seems to be wrong. My jetting is richer than every body else, alot richer, but it is what it wants according to the rattle. Does any one else had this problem with the 250cdi abd fly wheel.

[Roostius_Maximus]

i'm only at 50 pilot and 178m, and i figured that was alot.
did you to the 1/4 rpm hold and dial the airscrew to get it tweaked in?
its not got a vaccum leak between the boot and reed or something?

[fastkart]

Holy crap thats alot of a fuel!

[27maverick]

Its has new boysen reeds and the plug is dark brown to black, if there was a air leak it should be white correct? It is a 41, does any one have a 41 with 250 igniton and if so what is your jetting? My needle is a ceg in the richest clip. I believe a 58 pilot is going to be the next step, tried to call john at sudco but there closed until next year, must be making the big money?

[fastkart]

If there's an air leak, you'd need to richen your jetting alot to compensate. To check for an air leak with the motor running, take a can of carb cleaner and spray around the gaskets on for the reeds and the base gasket... if it changes how the motor runs, you've got a leak.

I have a Sudco 41mm PWK with a 250 ignition and at 1000' my main jet is around 185 depending on the temperature.

Reeds won't change the jetting appreciably. +/- one jet is about it.

[27maverick]

Checked the reeds, they were not good even though they were new. There was one side that was not closed very good. Bought a complete new boyesen rad valve installed it. Cleaned every thing up but I still have a stumble right as it starts in to the mid, like it is lean. When I went to a 55 pilot it was real bad, now with a 58 it's almost gone, maybe back to the 60. Installed the hydraulic clutch and going to try it to day. The master is a 9.5 bore, that's what the factory teams switch to instead of the 10. Feathers better and the feels better when slipping it. I switched to the 9.5 on my 300sx from the 10.