Very High Idle

[fatbiker]

As for doing the Shotgun and Peashooter, I assumed that since the carbs went in for a cleaning they wouldn't need anymore. I've decided that they were not cleaned properly and not every part that needed replacing was replaced. I knew they weren't going to replace the slide diaphragms as I asked them not to due to money constraints.

 

[davesax36]

Somewhere on here there's a video of my bike doing the same stuff yours is doing. A sync and pilot jet cleaning fixed mine. Does this sound familiar? I shut it off because it would just rev and hang and I didn't feel like making my neighbors mad.

http://www.youtube.com/watch?v=mxb4euGQlP4

 

[fatbiker]

As soon as I start my bike it immediately takes off and revs to 6K then slowly climbs higher. I am going to pull the rack, completely disassemble each carb one at a time for cleaning and inspection, plus remove all rubber boots including the v-boost assembly and check for leaks. If all this fails it's going to a local mechanic who specializes in 70's and 80's bikes.

On a side note, grey smoke pours out of the right muffler everytime I fire her up. Also, when I turn the bike off a sort of fog billows out of one of the carbs located on the right side. I assume this is where my problem is but I find it hard to believe that one carb can cause the engine to rev so high. Am I wrong in thinking this?

Fatbiker

 

[alorio1]

Do some research on screws that hold the intake ports on. On one of the intake ports one screw is longer and one is shorter. The PO might have these screws mixed up and the long screw is bottomed out allowing air to be sucked in and the short scew is not going in deep enough to seal off the oil gallery that it is screwed into. Maybe someone will chime in and correct me about which screws go where and on what cylinder this is on....but this could be your problem, then again I might be out in left field with this thought.

Here is a post that shows the bolts I am referring to...

http://www.vmaxforum.net/showthread.php?t=16994&highlight=intake

 

[jfeagins]

Yes, all 4 carbs are as far down in the rubber boots as possible. I used a rubber hammer to gently tap the down then tightened up the clamps all the way. I did have to loosen the connecting brackets and re-align the assembly to make sure they were level. First time around they were not.

As for the choke assembly, it SEEMS to work just fine. Right now it's warm here in Houston so if I turn the choke on it bogs down the motor. Off, it revs up to 6K and beyond.

As for doing the Shotgun and Peashooter, I assumed that since the carbs went in for a cleaning they wouldn't need anymore. I've decided that they were not cleaned properly and not every part that needed replacing was replaced. I knew they weren't going to replace the slide diaphragms as I asked them not to due to money constraints.

I can't imagine any clogging in the pilot jets causing a high idle - in fact, I'd expect that to cause the opposite, if anything at all.

To me, at this point, and without benefit of seeing those carbs my own self, I'd say you are going to have to re-pull them for addt'l disassembly and inspection. Perhaps you have one or more choke circuits with bad plungers. Maybe something wrong with one of the coasting enrichener diaphrams. Something somewhere is allowing more air into your idle mixture, otherwise it would not be allowing the revs to increase until after the main butterflies begin to open.

IMO, if you had anything seriously sticking in the float chambers, the bike would flood out and cause entirely different symptoms.

I wish you were closer to MO so's I could see them and/or help out in person.

Would sending them off to Sean, or Danny (the real carb gurus around here) even an option for you?

 

[tugla]

ive seen a/f out, sync out, stuck floats, clogged jets all cause that poping in the previous video. and either air leaking in, can be tested with unlit propane plumbers torch around joints and such, and also stuck or sticking slides holding up the idle like that. id take them off and start over, set sync by eye to get it close after going through the carbs fully and setting floats and while there check bolts and orings on intake along with all carb boots.
Im sure sean and dan have a more narrow search field but this get you in the right step.

 

[tothemax93]

Forgive me if this was already said, but could it possibly be a pinched throttle cable. Maybe its getting throttle upon start up. Maybe check and see if it's free. Just a thought. I went back and read the first post so I guess you already checked that. Is it still possible that the throttle isn't going completely back even though the cables are free.

 

[fatbiker]

Today I took apart the carbs and gave them as thorough a cleaning as I could. Installed them then did the Shotgun on them. At first when I started the bike it idled around 2K which is an improvement. I then hooked up the carb synchronizer and the vacuum on both carbs on the right side were thru the roof. I adjusted them to match the other two carbs and the rpm's went back up to 6K again. I checked to make sure the choke was closed on the two right side carbs and it was. If I open the choke the engine bogs down. I took at look at the carb boots and the v-boost boots to see if they looked bad but they didn't. I did not remove them so maybe I missed something. Perhaps and intake manifold leak? Valves out of adjustment? Something on the right hand side is askew. Suggestions?

Fatbiker

 

[davesax36]

Did you get the jets out of the jet block? I had smoke, high idle, coughing carbs... it was clogged pilot jets, terrible sync, and screwy idle adjustment screw settings. Cleaning just the bowls doesn't get the junk out of your jets and emulsion tubes.

 

[dannymax]

Today I took apart the carbs and gave them as thorough a cleaning as I could. Installed them then did the Shotgun on them. At first when I started the bike it idled around 2K which is an improvement. I then hooked up the carb synchronizer and the vacuum on both carbs on the right side were thru the roof. I adjusted them to match the other two carbs and the rpm's went back up to 6K again. I checked to make sure the choke was closed on the two right side carbs and it was. If I open the choke the engine bogs down. I took at look at the carb boots and the v-boost boots to see if they looked bad but they didn't. I did not remove them so maybe I missed something. Perhaps and intake manifold leak? Valves out of adjustment? Something on the right hand side is askew. Suggestions?

Fatbiker

Send them up, I'll put them on the test bike and see if the problem duplicates.

 

[Thevmaxrider]

Send them up, I'll put them on the test bike and see if the problem duplicates.

Excellent idea Dan-o! My first instinct is a major air leak somewhere, but it also sounds like there have been a lot hands on those carbs.

 

[fatbiker]

Not sure if I cleaned the jets in the jet block. Don't know what the jet block is. There was one section on the carbs that looked like a metal plate held on with 3 Phillips head screws. They were on so tight that I striped one and gave up on removing the plate. This is the only section that I did not disassemble and clean.

It's true that lots of hands have been on these carbs. I am owner number 3 or 4 and lots of poor work has been done on the bike. I'm working to get the bike back to stock then let the mod monkey run wild.

Even though it's possible, I find it hard to believe that only the two right side carbs are acting up. I believe it's a vacuum leak and I am trying to figure out the best way to go about solving the problem. Perhaps I'll buy new carb boots and v-boost boots and see if that helps out. Any idea the best place to buy these boots?

Sent a PM to you Dannymax.

Fatbiker

 

[Traumahawk]

I believe that Sean ([email protected]) sells them. Best way to get him is to send an email.

 

[dannymax]

Not sure if I cleaned the jets in the jet block. Don't know what the jet block is. There was one section on the carbs that looked like a metal plate held on with 3 Phillips head screws. They were on so tight that I striped one and gave up on removing the plate. This is the only section that I did not disassemble and clean.

It's true that lots of hands have been on these carbs. I am owner number 3 or 4 and lots of poor work has been done on the bike. I'm working to get the bike back to stock then let the mod monkey run wild.

Even though it's possible, I find it hard to believe that only the two right side carbs are acting up. I believe it's a vacuum leak and I am trying to figure out the best way to go about solving the problem. Perhaps I'll buy new carb boots and v-boost boots and see if that helps out. Any idea the best place to buy these boots?

Sent a PM to you Dannymax.

Fatbiker

Those little flat covers go over the coasting enricheners (shut-off diaphragms, anti backfire valves...they go by different names) They probly won't be causing your problems.

Got your PM, thanks.

Have you tried the unlit propane cylinder test for air leaks, point an unlit stream of gas at all the possible air leak locations, the idle will change drastically if you hit it....altho the 6K idle may complicate things.

The carbs need to be dismantled to this point for a proper and complete cleaning.

 

[fatbiker]

I have a can of ether that I used to spray around the carbs, boots, and any point I though might provide a leak. With the engine running at 6K and slowly climbing I could not tell if the engine surged due to the ether. I can un-sync (proper term?) the two carbs and bring the RPM down to 2K and try it again. Will give that a shot later today. If all else fails they're going to DannyMax.

Fatbiker

 

[jfeagins]

I'm watching this movie to the end. Can't wait to see where all that extra air is getting through.

 

[Redbone]

Just to point out the emulsion tubes in Danny's photo, lower RH corner of each carb section.
Precision work that Danny does for sure!

 

[dannymax]

I have a can of ether that I used to spray around the carbs, boots, and any point I though might provide a leak. With the engine running at 6K and slowly climbing I could not tell if the engine surged due to the ether. I can un-sync (proper term?) the two carbs and bring the RPM down to 2K and try it again. Will give that a shot later today. If all else fails they're going to DannyMax.

Fatbiker

Ether would probly work better than propane actually.

View attachment 42389

I'm watching this movie to the end. Can't wait to see where all that extra air is getting through.

Speaking of 'extra air'.................:rofl_200::rofl_200::rofl_200: Just kiddin'!! unk:

 

[fatbiker]

Looking at the teardown picture DannyMax provided, I could not remover the metal piece located in the bottom right of the box. Not sure if anything in there would cause high idle. The diaphragms in the top right of the box are not torn nor do they have any holes but they look like the original pieces. Everything in in the picture was taken apart and cleaned then reinstalled with new gaskets.

Fatbiker

 

[jfeagins]

The bottom right piece is the jet block. W/o removing it, you wouldn't be able to adequately clean the teeny weeny jets & passages in there. Those circuits do control idle mixture, but if partially or wholly blocked, would not create a high idle condition. IMO, the opposite would be occurring.

You didn't, by chance, remove and/or misplace one or more of the little rubber stoppers that position into one end of those jet blocks while you had them apart? If so, that might play hell on things.