VM Enricher/Choke too strong!

Hi guys.

Nearly have my tune perfect with the VM30's on my CB400N. However, one problem which I haven't found a solution for is the choke (I know, enricher).

The bike needs them on to start when dead cold, which is fine. However, when I flick them on and then start the bike, it will kick to life instantly and rev up to about 4000rpm and if I don't touch the bike, after a few seconds it will start to choke up and get too rich causing the rpm to drop and then stall (too rich). Now, if I flick them on and start it, kicks to life and revs up to 4000rpm, then flick them off, the idle will drop instantly to something way too low which then stalls (too lean).

I can work around this by upping the idle and that's all good for starting cold but then it's way too high once it's warm.

So the problem I'm seeing is that the chokes are way too strong and providing far too much extra fuel when they're on, but if they're not on and the bike is cold then it stalls. It makes starting when cold a frustrating procedure.

So, is there a way to lessen the effect of the chokes? Like, change a jet or block a hole or something?

interesting problem,it is actually the combo of air and fuel causing the high idle while on
you could experiment with some brass tubing and restrict the overall airflow at the bellmouth inlet passage
thats what i would try

Hmmm... it's not the high idling that's the problem. It's that it jumps up high (to around 4000rpm) then after a few seconds starts to drop and then dies without me touching a thing. My theory is that it's because it's far too rich as with any other bike I've had with an actual and gradual choke, you start it on full choke then drop it back to around 1/2 as leaving it on full not only rev's too high but will eventually stall it.

It seems strange to consider that I might be the only person with this problem. I thought if it happens to me it would be happening to most people with VM's. I guess I'm looking for a way to not only restrict the air, but moreso the fuel.

if you restrict the air less fuel should be pulled up as well
i dont think you really need 4000 rpm's anyway and it takes air to get a high speed like that
it is a start and would be easy to try,then you could play with restricting fuel in the pickup as well if need be

Try holding the plunger in a 1/2 engaged position and see if it helps.
If it does you should be able to bend a few things in the linkage to get it to engage only halfway.

that mite be the answer a lot of the 2 strokes what have cables on the enricheners use a friction adjust lever on the bars

My Mikuni carbs on my KZ had enricheners and you could set them at any level needed. I used to start on full most of the time and once started reduce to half.

Have you adjusted the pilot system yet? If not, it may be set too rich and then the added richness from the enrichener is just adding to the problem. Try getting the bike running and up to temp and then adjust it as per the VM manual.