Idle problem

[Marcarl]

So now that everything is back together, well almost, I have a nagging problem. Had the motor out for second gear, cleaned the carbs but did not break them down, just took out the diaphrams, used carb cleaner all over and through out, installed new diaphrams and all seemed to be good. Balanced the carbs last week and now I can't get the idle below 1500. All carbs are balanced but I have a problem with #1. When I take the plug off of the vaccum port there is very little change in the engine. Not so with the others. When I took off #3 the engine almost died, #4 and #2 there is some change as would be expected but not enough to worry if the engine will die. I replaced the lower throttle cables but they are all slack, the idle speed screw is backed right out, I checked the chokes and they are all pushed in. Sometimes though, the idle will come right down and momentarily behave as it should, but mostly not and I cannot controll it.

I need more ideas,,,,,,,

[StarFan]

Pilots screws properly adjusted?

[Marcarl]

Pilots screws properly adjusted?

Never touched them, so they should be good enough. I think.

[scotty]

It sounds like a nasty vacuum leak. Are the carbs all fully seated in the boots on the engine?

Scotty

[Neil86]

First remove airbox lid and filter...are all the slides closed up or is there one stuck.....and check the throttle butterflies are all relatively closed. Roll on the throttle and release to see if they consistently return to closed. I would do these checks with engine off.

If your YICS chambers are still hooked up....check for damage to the hose or the chamber itself.....the seams separate over time causing intermittent leaks as the engine vibrates. Several 83-85 bikes run with the YICS abandoned.

[Marcarl]

It sounds like a nasty vacuum leak. Are the carbs all fully seated in the boots on the engine?

Scotty

They are that, seated well, everything looks good. Thing is, sometimes it idles well and other times it just won't come down. Take the plug off and there is very little change on #1, put the carb sync on and I pull 14 in. vaccum?????????????????

[Marcarl]

If your YICS chambers are still hooked up....check for damage to the hose or the chamber itself.....the seams separate over time causing intermittent leaks as the engine vibrates. Several 83-85 bikes run with the YICS abandoned.

Took it out last year, and sent it on it's way. Now have the vaccum hoses \ports: #1 to #4 and #3 to #2.

[Neil86]

Check your Jason mod hoses then....some can't take the heat and disintegrate.

Sorry for asking but the carb synch was done with the Jason mod hoses removed and ports capped correct?

[Venturous Randy]

Check your Jason mod hoses then....some can't take the heat and disintegrate.

Sorry for asking but the carb synch was done with the Jason mod hoses removed and ports capped correct?

 

Good point. Carl, how does it idle with the sync tool hooked up? Also, recheck your plugs on the YICS ports. I had a plug that split. Try running it with the Jason mod off and ends plugged and see how that does.

RandyA

[Neil86]

Took it out last year, and sent it on it's way. Now have the vaccum hoses \ports: #1 to #4 and #3 to #2.

 

Okay....this may be part of the problem....the Venture cylinders are numbered

front left-#2......front right-#4

rear left- #1......rear right-#3

 

You want the hoses for the Jason mod hooked up (1-2) and (3-4).

[BradT]

It Could be dirt in the carbs as well. Had similar problem before and they were just dirty

 

Funny how everything worked before your fixed it.

 

BRad

[Condor]

A couple of times when syncing, I've set the idle on #2 at 1000 rpm and then did the sync dance. When balancing L to R the idle would increase a bunch. Reset the idle back down to 1000 on #2 and re-sync'd. No problem with idle after that. I think... what's happening is the first time the idle was set the off side carbs were actually controlling the idle even though the screw is on #2, because they were set tight. When I balanced 1&3 to 2&4 it open the 1&3 butteflies up even more and the idle increased.....maybe???? Since then I generally back off the 1-3 screws about a half turn and I can't remember having problems any longer..... or maybe I'm just lucky...

[Marcarl]

Played with it all day yesterday, off and on and then when I was done playing with the cables it idled. OHHH right, but when I turned the idle screw down, nothing changed, so I got it to idle, but something is still wrong. So we went out for supper last night, carb cleaner in the tank, wifey on the back, all the way to Cambridge, about 40 minutes, and all was well. On our way home it decided to start this fool game again and idle at 1500. Now when I crank hard on the throttle, in the reverse direction of speed, I can bring it down somewhat. I think a deeper investigation into cables and such will be in order. For now I'll ride and all you folks stay out of my way, you are forwarned!!!!!!!!!!!!!

I'll let you know what the outcome is, probably something little and easy, and possibly even a little dumb. Who knows? IN the meantime I'm open to more ideas. Got lots of things to check out, enough to keep me from riding all summer, as though that will happen,,,,,,

[muffinman]

Carl I know what the problem is

Look in your service manual (paper one) there is a not in the carb section that says DO NOT MOVE THIS or some other such wording.Get that cable set back to the factory setting and your problem should be solved.It took me 4 days to get it right on the 84 after I adjusted the cables like and idiot that I can be.

It is hard to believe but this one cable can cause all kinds of problems with the idle on the first gens and it will make the bike run real weird I thought I had a real problem with the coils till I actually read the book.Sorry I cant give you page number but I am at home and I think that the paper manual is in the Rv.

Jeff

[Marcarl]

Well I solved the problem, sort of. First off I found it really helps to have the throttle stop screw backed off far enough so that it will kill the engine, I did, but the sync screw on #1 was was also backed off too far and so that screwed things up some what. Once I discovered this I was able to get the sync perfect and it ran better but the idle would still hang up when it warmed.

So the next thing I did was to adjust the cables to factory spec's, as I was informed, and now it will idle at 900 rpm, but it still hangs up at 1200 rpm, although with a little push on the throttle it idles fine. Don't know quite what to do about this, but someday I will find it and then all will be well. As it is, I ride and enjoy.

[Squeeze]

Carl, i think you have either a minor Vacuum Leak or there's a lean Conditon in the Carbs. A missing O-Ring on a Daiphragm Bowl could probbably also cause this.

[93 venture]

I seen where you had cleaned the out sides of the carbs, have you tryed lubing up all of the moving parts on the carbs and cables?Maybe sticking from being dry.