we started the mikuni tm40 pumper carb project. we put the carb on with a crude step ring and got it running using suzuki dr650 jetting. seemed to run ok but we could only blip the throttle by hand since we did not have a throttle cable that fit. the actual carb is an hs40, the harley version of the tm40.
 now were looking for the correct head to carb rubber boot to fit the pumper and also having a throttle cable made up. it looks like a ls650 cable with suzuki dr650 fittings at the carb will do the job. more later.

not the carb to filter boot, that was not attached at this point. the head to carb spigot.

here is the other side of the carb.

i wound up with 2 of these carbs, i won one on ebay and snagged one at a swap meet the next day. both were ex-harley carbs that aside from the jetting are the same as the mikuni tm40 pumper. the conversion for the suzuki dr650 with the tm40 is well known, as is the correct jetting. i set one up on my dr650 over the winter. i would not make a claim for massive hp gains, but the motor comes on right from the bottom and any surging is gone. instant throttle response, well worth the effort. so the 2nd carb is being installed on the neighbors ls650. procycle.us stocks the tm40 carb, jets etc.

Well done on the mikuni pumper, I have a keihin FCR41 with ap.
Clive W  

No my FCR does not have a decel bleed valve, it's the earley model (not mx) I got it in '02, it was one of the first ones with a choke, still needs a couple of ap squirts to start though.  

Clive W  

I have a slightly rich idle setting which helps starting also I have tried new needles with richer parallel sections and have setteled on one step richer than o.e.
I have ordered another needle with a 1.25 degree taper (o.e. is 1 degree) to try, and have a selection of main jets (160-185) and main air jets (190-220).
Here is a pic.

Clive W