Carb vent/crosswind stumble/etc

[mustangGT90210]

Alright so I've seen a few things about the cross wind stumble and other stuff related to the carb vent hose. But no one seems to have the same thing going on I do. I don't have the plastic T in my carbs that the vent hose would even hook up to. I imagine it broke or something before I bought the bike.

What kind of issues could that cause?

[Badot]

Alright so I've seen a few things about the cross wind stumble and other stuff related to the carb vent hose. But no one seems to have the same thing going on I do. I don't have the plastic T in my carbs that the vent hose would even hook up to. I imagine it broke or something before I bought the bike.

What kind of issues could that cause?

Fuel starvation symptoms at speed and/or with a strong crosswind.

[mustangGT90210]

Guess I should make up a couple hoses and run them to the proper place then! I've got a serious stumble at speed, hopefully this is the cause

[bombsquad83]

You should also clean your gas tank vent if you haven't ever done it.  It helped my issues with lean stumbling.

Check out ben2go's tutorial in the FAQ section

[dmoore]

Where is the tank vent located?

[bombsquad83]

The vent is integrated into the gas filler cap.  Here's the link to the tutorial. http://gstwins.com/gsboard/index.php?topic=41061.0

[mustangGT90210]

My stumble is in all gears at the most minute of throttle openings. Like only when I'm just cruising to maintain one speed it pops and stumbles. Could that be a mix screw thing also? I just re jetted to 150/40 with a straight pipe and lunch box.

I'll check into the gas vent next time I get a shot! Never actually rode the bike with the gap I got from addidas before the re jetjet so I'm still figuring out the kinks in my tune.

[adidasguy]

Probably all the rejetting and stuff - you're to lean? (adjust mixture screws)
Carb float height? (check with a clear U-tube from the drains).
  Gas cap: try running with cap open if you suspect that. If it is, clean the vent hole.

[jestercinti]

My stumble is in all gears at the most minute of throttle openings. Like only when I'm just cruising to maintain one speed it pops and stumbles. Could that be a mix screw thing also? I just re jetted to 150/40 with a straight pipe and lunch box.

I'll check into the gas vent next time I get a shot! Never actually rode the bike with the gap I got from addidas before the re jetjet so I'm still figuring out the kinks in my tune.

Gas vent...When it stumbles, stop and open your cap.  Do you hear a 'Woosh!!??"  If so, you have a cap vent issue.
Look for kinked hoses.  Look for hose routing.
Then look at the float height
Did you turn on the tank petcock all the way?  Look at the notch.  "--" means off, "|" means on.  <-- Straight up and down.  Not "/" or "\"

[Badot]

Do you have your needles shimmed?

[mustangGT90210]

Float height I eyeballed cause it was a little off before, guess I'll check that again!

Needles are shimmed with 1 washer, per the wiki for my set up

I'll try running with an open gas and see if it helps, hope its something simple like this

Hoses are all good, I'm anal about that and the tank petcock because they got me me before.

Thanks guys! I'll be back to bend your ears Thursday after I check out these ideas!

[mustangGT90210]

Float heights checked out perfect, turns out my right carb didn't have a washer under the needle (coulda swore it did), so now both carbs have a washer. They are split washers that I put back to the proper shape and it all slides smoothly though. I read the plugs and they looked pretty decent, first time I've seen chocolately color creep into them in a long time!

So today, float height, needle shimming, mix screws set to 3 turns out. Stumble is gone, power delivery is smooth! But I've introduced a new problem.

I've got a idle hang now. Before I messed with the stuff today, this bike idled phenomenally and didn't hang. Now it runs great, but has a hanging idle sometimes. I used carb cleaner to check for air leaks, and yielded no results. Could sticky slides cause an idle to hang? I'm pretty stumped where it came from.

[Big Rich]

Not the slides - because without the butterfly valves being open sucking more air in, the slides don't mean much.

So.....air leak or a sticky throttle cable.

[mustangGT90210]

Throttle cable isn't sticky, it snaps back every time as it should.

Where else is there to look for an air leak aside from the diaphragm covers, and the intake boots? I have a lunchbox on the bike also

[bombsquad83]

Make sure you didn't loose the small o-ring that goes between the carb and the diaphragm cover for the sync port hole on either carb.

[mustangGT90210]

Make sure you didn't loose the small o-ring that goes between the carb and the diaphragm cover for the sync port hole on either carb.

I have not, I'm careful about that since I found out the hard way lol. Could it be one of them is old and that causes my issue? I've got one that's a year old from when I rebuilt the left carb, and the other one is who knows what age, and overall a LOT thinner of an o-ring

[Calpantera]

Make sure you didn't loose the small o-ring that goes between the carb and the diaphragm cover for the sync port hole on either carb.

I have not, I'm careful about that since I found out the hard way lol. Could it be one of them is old and that causes my issue? I've got one that's a year old from when I rebuilt the left carb, and the other one is who knows what age, and overall a LOT thinner of an o-ring

Did you change the slide diaphram and not the oring? If the oring is thinner it might not be seating correctly..

[mustangGT90210]

Well, one side has a new diaphragm, the other has a new o-ring lol. Hopefully that's the issue here!