Pardon me for bringing up the jetting question again, but I can't seem to find the answer I am looking for, even after searching the database.

I will be changing the Keihin mains to Keihin 142F and 145R. I want to know if the needle on each carb must be changed out also after doing the mods? I know that the Dynojet needle has notches so that it can be adjusted. Does the factory needle have these notches also? What alternatives are there to the Dynojet (besides the Dial-a-jet)?

The mods will be:

Twin-air filter (already installed)
Snorkle
NYROC Muffler drill-out (six 3/8" holes)
My primary riding elevation is 800 ft.

 

No notches on the Keihin needles. Buy some tiny washers to shim up the needles; total thickness of the washers in the .04 to .07 inch range ought to do it.

 

Ah..., no notches on the factory needle, but do you still need to shim or otherwise adjust it?

For the washers, I understand a .04 to .07 inch range of thickness, but what about diameter? Since I haven't taken the old ones out, I must confess I really don't understand the physical arrangement of the needle in the carb and how the washers will fit in. I will figure it out when I take it apart, I just want to have the parts and materials on hand.

 

you can cut some shims from coke cans, or a #4 brass washer should be pretty close. most carb shims are .020 more or less, becuase the typical needle clip positions are .040, so they are half a step. most stock meedles can be shimmed with 3 shims if need be.

mine runs fine like it is, and fla is kindof flat..no shims needed on mine, but I don't have the muff mod. all the shims do is richen the midrange up more.. it is still a function of the main as how much total fuel (top end) is passed..with the muff mod, you may need to shim the needles, or may not, or you may need 1 size bigger main in..but if it were me, I'd go with 142/145 turn the mix screws out about 1/2-3/4 turn and see where I was from there..it ought to be close..

 

I used a #4 sized washer from a hardware store. Duh, I'm 10 feet from the washers and my caliper, I'll measure it for you - just a minute.............. I'm back. The washer thickness is .025 and the diameter is .282, just over a 1/4 inch. They fit nicely down inside the slide.

I used 3 washers stacked, but 2 may do the job. Just slide the washers on over the needles, and drop the needles back in their recess in the slide. Hope this helps.