Crazy high idle

[Yfx4]

I took the fat chick out for a ride this am. It started fine, idled great when I left. about 30 miles out I saw a popo and lowered the throttle hand, it did not slow down. made a couple stops, it would not idle less than 3500, sometimes 4500. Yes, the choke was off......

I checked the cables...they are slightly loose and both push/pull. they idle screw makes no appreciable change.

I am guessing there is a vacuum leak? The carbs were rebuilt/synced 250 miles ago and it ran great until this am.

Where to start on the vacuum?

Christbiker......when is the next wrench session?

edit:   Forgot to say, when I shut it off I used the kill switch and it either backfired 2x or had run-on that I had to stop by putting it in gear and release the clutch.

 

[Patrick]

The idle increases on its own to 3500 or 4500 ?

How does the throttle feel ? Does it work and feel like it should ? Does it have a lot more free-play ?

When all shut down and quiet, can you hear the throttle coming back against the stop ?

Have you removed the hand throttle to get a good look at those cable ends ?  Or raised the tank to look at the carburetor end ?

[Yfx4]

Once it warms up the idle never goes down below 3500.

The throttle feels ok. I took the cover off the throttle  and inspected the cables they work fine and show no unusual looseness. I have about 3/8 inch of rotational play from hand off the throttle to cable tight.

I have not pulled the tank.

I hear it hit the stop when I release the throttle and let the springs pull it back.

[Ricky-D]

I would say the first thing to do is to slather (spray) all the linkage

on both sides and behind the carbs also with some kind of silicone spray

or lubricant. Remove the chrome covers to help access all

areas, springs and stops.

Not to worry about a mess at this time. It'll clean up easily.

***

[Yfx4]

Would it be easier to access if I pull the tank?  Or can I do it all together?

if I push up on the throttle linkage between the rear two left carbs I can get the idle to go down....it pops up again when I let go.

[Patrick]

It sounds to me as though you have a linkage issue, something is not right. Seems like the tank and maybe the air box needs to come off. 3/8" is excessive and maybe the problem with cylinders 4 and 6 linkage needs to be looked at.

[Yfx4]

I lubed all the springs and linkage.

Tightend the cables so there is almost no play in them.

in the garage it idles just below 1000.......it did before too.

I will take it for a ride later or in the am to test it.

thanks for the ideas. I don't really wanna pull the tank. ......the honey do list is long.......happy wife and alll......

[salty1]

Curious  to hear how this worked out for you. ???

[Yfx4]

I am too......

[Ricky-D]

It is imperative when tightening the pull/push throttle cables to leave

ample slack in the cable system.

Slack should be adjusted with the handlebars turned all the way to

the stops, both left and right side.

Failure to properly adjust the cables can lead to throttle linkage

damage, broken throttle parts along with premature wear on all

the throttle components.

An improperly adjusted cable system can also cause a sluggish

throttle return which, in cases can be dangerous for the operator.

***

[Michvalk]

Or, it could be vacuum plugs on the intakes leaking from cracks

[Yfx4]

Lube on the throttle links seems to have done the trick. I was able to get out for an hour yesterday am.......it all worked great. It idles at about 1100 now....I will adjust that.

thanks for the reminder about throttle slack. I did adjust it and check it with the bars turned both ways.

Thanks again for all your help!!!!!