Mikuni Jetting 1974 CR 125 - Experts ?

[mtbrider]

The Mikuni is finally on with my home made remote choke and it is running and idling well. Current specs are:
Mikuni VM 32
main  4 / 042 200
pilot 35
needle jet 159 Q6
jet needle 6DP17
throttle valve VM 34 / 110  3
air jet        BS30 97 2.0
needle valve VM 34 / 39  3.3

Seems fine up in the rev range however is bogging down badly from take off. The needle has a very aggressive taper so it seems to be dumping too much fuel in when you throttle on drowning the plug.
Tried a 6F76 of a 250 but same problem. Any ideas on size to stop this problem.

[JC]

With my limited knowledge of jetting it looks like too big a slide cutaway for 32mm on a 125.
A 2.5 maybe worth a try instead of 3.0.

Having said that, my Mik manual specs for VM32 are as you've listed except 6DP5-3 needle, but its recommended for 200-250cc 2T, not 125.

The manual gives specs for 30mm for CR 125 Honda if thats any help. (I have found that they are often close as a starting point for the next size up carb)

Also I did have some specs from a friend who ran Miks on CR125 Hondas, but can't remember what size. Will see if I can find them if you like.

[Graeme M]

I'm no jetting expert but a Q6 sounds mighty rich for the needle jet. The specs for an RM125S with a 34mm suggests a P3/P4, which is several steps leaner. Worth considering?