Carbs ?

[Rick Morrison]

Can anyone ID these carbs ? Thanks

[onchiman]

They're Mikuni VM style carbs.

[Nessism]

They look like the stock VM26's as installed on pre 1980 GS750/850/1000's.

[rustybronco]

Look at the left carb with the open vacuum port, someone has had those all jumbled up.

number 2? in the no 1 position, un-capped.

[Rick Morrison]

Thanks ! Now for another question. My bike seems to run great except at idle. The idle will randomly fluctuate, its more annoying than anything. I've tried to adjust the idle by way of the idle screw, but if I have it set high enough to keep it running eventually the idle will run up to 2500-3000 rpm. Is there a ghost in my bike ? Weird !

[hampshirehog]

I should let Rustybronco reply as he spotted it - your vac tube is open and drawing in air - you'll never get the bike to run well like that. You'll need to remove and split the carbs and re-order them.

[Rick Morrison]

rustybronco, I've never messed with carbs before. What do you think should be the first order of business dealing with these ?

[rustybronco]

I would take them apart, check that they don't have mis-matched jets and clean them.

but the bigger question is what did they do to the no 1 carb, replace it with a no 2 and plug the fuel and vent holes, or did they mix them around.
I think I can see evidence of the fuel rail hole plugged off with something...

how many vacuum ports (not the vent connectors) are there? if you have a port on the No 2 carb, then you can try to cap the vacuum port on the No 1 carbie.

***how about a better picture of the No1, or of the carb rack with the tank off***

[Rick Morrison]

I'll try to get some pics posted with the tank off later today or tomorrow. Thanks !

[Big T]

The first thing I would do is to put a cap over that vent port on the #1 carb and see what happens. That may solve your idle issue after you readjust some settings

I also see that the float bowls are on the wrong sides

[Rick Morrison]

I don't have a vent cap, do you think some electrical tape would suffice to test it ?

[Big T]

Duct tape or a heavy piece of plastic sheet and a tie wire or zip tie.

Anything that will block it.

You can probably get a cap at NAPA

[rustybronco]

A piece of vacuum hose with a small bolt in it will do nicely.

***EDIT*** But the question still remains... are the carbs vented properly.

[rustybronco]

this should help

VM26SS carbs that Bryan (bplubin) and I finished tonight.
no port on the No 1 carb.



No 2 is the vent for 1&2, No 3 is the vacuum port for the petcock, No 4 is the vent for 3&4
they must be assembled correctly or you may have a vacuum port that is open to atmosphere where it shouldn't be.