Complete carb frustration

OK, heres the history. I have later model VM28 pumpers. I got my bike last year and It ran good carb wise. 1 start kick, ideled nicely, smooth enough part throttle to a little hiccup higher in the powerband at like 3/4 throttle. Bike seemed to fall on its face around 90mph and didnt like being there with a lot of hesistation.
This winter I did a lot of stuff to the bike. Taking off the carbs, cleaning them and putting bigger mains in them was one of them. I also did my routine maint stuff. New oil filter, new fork oil, upgraded to a combo reg/rect unit. New brake pads, New throttle cable, (return cable was fine), Installed rear Ohlins shocks, bobbed rear fender, custom seat pan and seat...etc. All in the wrenchmokees/bratstyle bike style.
So leap forward to now, its springtime, I want to ride, I button everyting up, go for some intial test runs to bed the brakes, check for leaks, adjust carbs....I have bench synced them so far, pilots all 1 1/2 turns out....But heres were the problems start. After putting the carbs back together, one of the slides is sticking. If I manually crack the throttle open and let go it goes down about half way and then just slowly falls to normal position. Its not the cable btw, Im doing this on the bench. So I go through and reclean everything with a couple cans of carb cleaner and it seems to be snapping open and close nicely. so I put them on the bike after a day or so and its doing it again. I then take em off and recheck and I remove the set screw off the slide lever arm and its carb #4 thats the offender. I crack em open and shut without slide #4 and it works. I tighten it back down finger tight and its sliding nicely again, I figured I had that bolted too tight on the shaft so easy fix. So its all moving smoothly again. The next day I go to test ride again and its sticking I cant figure it out.
It starts on 1 kick. I let it warm up half choke for a few mins. I crack the throttle and it pegs at like 3-4k and wont go down. No air leaks (I checked) No binding cables no nothing. I cant get them back down with out letting them go down on their own. Sometimes they go down quicker than other times.
This makes the test rides unsafe and I cant even begin to tune from the jet upsizing. Its all jerky when going through the upper rpms to lower rpm transitions....
Ive taken these carbs off about a dozen time for different reasons and I just dont know what to do next....
Pay a few hundred dollars to get them rebuilt? Get some later model Police CV carbs? Get some uber expensive Kehiens?

I JUST WANT THE BIKE TO BE RIDEABLE!!!! :laugh: should I go back to the VM26s and start over?

I had a similar problem on a Kaw S3-400cc triple (2 stroke). With the carbs right in front of me, caps removed from the top, I had all 3 slides sticking.

The amount of varnish on the throat of my carbs and on the slide was so intensely packed on and hardened, I fooled myself several times with Carb Cleaner thinking I'd got them clean.

After all, with the carbs on my white dinner tray right in front of me (I watch Bloomberg TV and clean carbs with a TV dinner tray) -- the fugging slides moved freely enough.

My theory is when they were back on the motor and got hot, the remaining gas varnish was revived by the heat and started getting sticky again due to the heat.

My solution: I gave up using a can of aerosol carb cleaner.

I was real frigging mad, sort of like "I'll show you mofuggers" sort of deal, I tore them down completely, all plastic and rubber bits removed.

I then bought three 1-gallon cans of Berryman's carb cleaner and put all the metal bits of each carb into a separate can of the Berryman's.

I let them fuggers soak for 3 days, I showed them who the hell is boss.

Problem solved. No more sticky.

The important thing here is in my case it was not easy to notice the hard-baked, thin varnish residue on the slides and the carb throats, it was near invisible, but nobody hides from Berryman's carb cleaner gallon cans.

I think Berryman's is the Navy Seals and the gottdang varnish was Osama Bin Stickin,
we know how that one went, Berryman's is a real basterd in these cases.

I still have my S3-400cc and it runs great.

if newoldkz1000's approach has already been done (which was agreat description btw. :lol: ).

i would be tempted to pull that slide out,and after looking in the slide bore for varnish/obstructions.give the inside of the slide bore a few light strokes (with some scotchbrite wrapped around my finger) twisting up and down as i went to create a cross hatch pattern.
5-10 strokes tops,you are not trying to remove metal just brake the glaze(so to speak).i would then do the same to the outside of the slide,just a few strokes again not trying to strip the chrome.

heat expands,cold contracts.this is known

i am thinking they get hot and the carb bodies are swelling up enough to grab a slide that may have some scratches/burrs on it and start sticking.

just a thought,i am no carb expert.
hth,

leon

These are great ideas. Thanks. Im going to try to find a gallon of that carb cleaner. Napa maybe? Im going to take off the carbs....again....and work that slide issue out. :S

Thanks for the help!

hal0tw0 wrote: These are great ideas. Thanks. Im going to try to find a gallon of that carb cleaner. Napa maybe? Im going to take off the carbs....again....and work that slide issue out. :S

Thanks for the help!

I bought my Berryman's at Napa.

This might not apply, because it sounds like the slides are fine when cold, but have a look at the needle and see if it's bent or tweaked a little and rubbing up against the jet that the needle slides in and out of (aka the 'needle jet').

I was working on a Suzuki 600 Bandit and the prior owner, when reassembling one of its 4 carbs, was putting the slide back down into the throat of the carb and did not notice that the needle wasn't lined up into its jet -- the needle got hung up on the floor of the carb and he pushed the slide to force it down and bent the needle a bit, then realized the slide wasn't dropping enough, he pulled the slide back out and then put it in again -- and the bent needle this time lined up and slid into the jet.

I discovered this when I pulled the carbs apart for cleaning, he dumped this '99 600 Bandit because he couldn't get the carbs sorted. The needle will rotate and will rock a bit but this one was tweaked. Could have been binding in the jet. Runs great now.

May not be what's causing your binding but worth a look, and good luck to you.

after soaking them in the berrymans make sure to scrub them down really good with regular spray carb cleaner,the gallon can of berrymans i bought recently at autozone seems to be leaving a film like syrup on parts after extended soaking if i dont spray parts down with aerosol cleaner after removing them. :blink:
im going to harbor freight today and looking at ultrasonic cleaner

I visually checked the needles and they all apear to go straight in with no kinks. Its still slide #4 that is the culprit. I'll try to spend some time on them this rainy weekend to sort it out.

Another note, I did use Sta-bil in the tank this winter. I still started the bike up and ran it for a few minutes every month untill I took the carbs off. I know Ive read stories about them gumming your carbs up and not to use it....
Any truth to that?

After the carb bath, would brake cleaner be the best bet as that leave NO residue behind?

I just want a bike that is reliable. I dont need top speed....ive had that with my R1, I want a ride with no suprises and Ill sacrifice a few hp to make the bike enjoyable.
Im even thinking of BS34s and the stock airbox......but thats a whole other discussion....

Thanks for all your help!