vm 26ss carb air jet

[Anonymous]

Hello

Does anyone know if you can remove the air jets on these carbs. I am refering to the air holes at the mouth of the carbs where the air filters go on. Someone suggested that I had a idle curciut problem (fouling on all four plugs no idle without the help of a throttle) I have looked at the links that have been generously shared with me, but the carbs are of a slightly different configuration. And although I can see something in these access holes they don't appear as though they can be removed. However this doesn't make any sense to me.

Thank you once again

 

[Billy Ricks]

The only difference between your VMs and the ones in the link is the way the slides are raised. Everything else functions the same. I don't think there is anything at the mouth of the carb to be removed. There is a screw that controls the amount of air going through the idle circuit. Consult the guide I gave the link to.

 

[frosty5011]

No, the air jet as pictured in the above CV carb........cannot be removed on the 26mm VM carbs. At least not with a screwdriver. They seem to be fixed-size pressed-in brass inserts.

 

[KEITH KRAUSE]

They should not need to be removed unless someone butchered them.
How about some more info about your rich carbs? What model are they on and what mod's, etc. I'm sure we can help.

 

[saaz]

The air jets are probably the last thing you want to try and change. The pilot jet, pilot scew and air screw can give you a lot of adjustment, and will be a challenge to get right.

 

[Anonymous]

They should not need to be removed unless someone butchered them.
How about some more info about your rich carbs? What model are they on and what mod's, etc. I'm sure we can help.

Hello Keith,
Well they are Mikuni vm 26 ss's, The bike is a 79 gs 850 I'm running pods, 110 mains 17.5 pilots, and have raised the needles and stock 4 into 2 with no baffles. The bike ran great before the top end rebuild (plugs were tan). The bike still runs great except the plugs on all four foul badly, and the bike won't maintain an idle. I've cleaned the carbs very well. I've noticed that the float needle seat o rings are shot on a couple. Could this cause the rich problem? Should I raise the float height, I set it at 24mm. The petcock is on an aftermarket tank, it is a simple on/off style(no vaccum activation. Thanks :lol:

 

[Billy Ricks]

If you have dad o-rings on the float needles or the float valve bodies then even with the floats set right the carbs will flood. There are o-rings on the float valve seats that can dry up and fuel gets past there.

 

[Anonymous]

If you have dad o-rings on the float needles or the float valve bodies then even with the floats set right the carbs will flood. There are o-rings on the float valve seats that can dry up and fuel gets past there.

Hello,

Could I just match up these o rings with something from an auto store?
I know that if I order them via www or a bike store that it will take forever to get to me.

Thanks

 

[Billy Ricks]

What I found that is almost the perfect size are the o-rings that are used to repair the pump up garden sprayer tips.

I have gotten o-rings for them at PepBoys. You won't find quite the right size most likely. They are usually too thick or too thin. I used the ones that were slightly too thick. But I got them considerably smaller than what was needed then stretched them over the seats. A little oil on the o-rings keeps them from breaking when you stretch them on. Also use a little oil to palce the seats back in the carbs. This will keep you from shaving any of the o-ring off inserting it in the carb body.

 

[Anonymous]

With respect to the Orings, Robert Barr is creating a kit for the VM carbs. I sent him a carb from a '78 GS750 and he is measuring and ordering the correct rings. I expect to hear from him soon. When they become available all of us with the VM carbs will benefit greatly.


Harrison

 

[KEITH KRAUSE]

Hello Keith,
Well they are Mikuni vm 26 ss's, The bike is a 79 gs 850 I'm running pods, 110 mains 17.5 pilots, and have raised the needles and stock 4 into 2 with no baffles. The bike ran great before the top end rebuild (plugs were tan). The bike still runs great except the plugs on all four foul badly, and the bike won't maintain an idle. I've cleaned the carbs very well. I've noticed that the float needle seat o rings are shot on a couple. Could this cause the rich problem? Should I raise the float height, I set it at 24mm. The petcock is on an aftermarket tank, it is a simple on/off style(no vaccum activation. Thanks :lol:[/quote]
If you have bad o-rings on the float valves, a rich mixture will result. Replace them. Be sure you get o-rings that are for gasoline.
Sounds like something involved with the motor re-build is causing the problem. There are a lot of things that can cause all 4 cylinders to run rich. We'll throw out "inside" jetting because you said it was fine until the motor re-build.
Before changing things inside the carbs, you need to check the ignition timing first and make sure the plugs are all firing well and at the right time. Be sure the plugs are the correct rating and gapped correctly. The battery must be strong enough too. Valve clearances need to be within spec'. The carbs need to be synched with a vacuum tool. Air filters clean and oiled (if they use oil). On your carbs, with your filters, I would try setting the pilot screws (underneath) at 1 1/2 turns out. Then set the side air screws for the highest rpm. Warm up the bike first and then set them in 1/4 to 1/2 turn increments until you achieve the highest rpm. Turn "2 at a time" to more easily hear the rpm's. Then turn the idle down to about 1,100 rpm using the idle screwknob. Make sure the vacuum nipple that fed the petcock is plugged good. Remove the 2 floatbowl vent lines. They should be removed when running pods. Now sinc' the carbs if all the above is right.
If all of this is done and you're still too rich, let us know.

 

[KEITH KRAUSE]

Another thing. Did you replace the rubber manifold o-rings? If not, replace them and put some hi-temp' bearing grease on them to help them last. You can't do any adjustments with poor manifold o-rings.