Motorcycle Idling a little high, wont come down. Advice?

Question

I have a 1982 Yamaha Virago 750cc's. I just tore apart the carbs and cleaned them out, and replace the spark plugs. Made some other minor repairs. Now the bike is back together. Fired up Beautifully. But it's Idling around 3000 RPM and wont come down.

Before the repairs the idle would wander incessantly, climbing up for no reason, or bog out and stall. So I'm glad its holding a strong steady idle, but is 3000 RPM a good Neutral RPM? Is there a way to drop it down?

Before you mention the obvious: I did not make any adjustments (that I am aware of) to the carbs so that they would run richer. Yes, the choke is completely closed, and yes the limit screw on the Idle control is all the way down. Still holds at 3000 RPM.

My one guess is that when I re-installed the throttle cable on the carbs, I may have taken out too much slack. Like to know if there is anything else I should look for next time I have the tools out.

Thanks.

I did all the mechanical work myself. I'm not letting anyone else near this bike.

Its a virago, the air intake is under the seat. There is no horn to obstruct.

Even if the air intake was obscured, that would cause the engine to suffocate and stall, not run rich and climb. Correct?

And keep your opinions on Yamaha to yourselves. I'm here for technical advice.

Answer 1

Your thought about the cable adjustment is a good one.
Another thing to look for is the cable routing. If it is not in the right place it can become tight and cause the same thing. A second would be if the tang that the screw sits on is bent. The item that clues me to this is the fact that your idle is at the very bottom. This is never the case unless something else is out of place.

3000 is high. I don't know the spec, but it should be closer to 1000.

Added: If the intake was obstructed it would run rich and slower, not faster.

Answer 2

I had a virago 920 and a 750 they were my first bikes. I had to do some carb work on them.First off when you had the carbs off did you check the float level on each carb and you can do that by hooking a clear line on your bowl drain hold the line straight up and it will show you the fuel level. Make sure your throttle cable is not snaged up and is working properly. You might have to set your main idle I set mine to 1200rpm make sure your boots for air intake is not leaking and to check you can spray some either in there while it's running. Check your pet cock to make sure it's not cloged and maybe slip a new screen in there make sure your tank dont have junk or rust in there because cleaning them carbs get old fast I pulled mine off atleast 20 times yeah it got old but did get it right. The only thing I hated about the virago is the engineering of the starter,yeah and they cost three hundred bucks. Make sure you have good compression good plugs ngk's work great with the propper gap. And if you do all that and it still has problem your fuel and air mixture will need to be set on each carb that will cost $50 bucks to have the bike shop adjust that for you if you dont have a jet kit. Thats about it I hope that info will help you goodluck

Answer 3

I used to have one of these...i had the same problem. Problem one-Hitachi carburetors. The throttle linkage binds up from time to time, it may be dry now that you've cleaned it all off. Little wd40 of 3-in-1 should help.
Make sure the retaining nut on the throttle linkage is snug but not tight.
Next problem-Cable routing. I noticed one day that the bike would coast on a left corner, but have torque on a right. Cable was routed wrong when I bought it, I actually bought a longer cable for it, took care of that problem.
750 v's are good bikes, so good luck.
Keep the shiny side up, Brother.

Answer 4

To get the carbs off those bikes, the intake manifolds usually get removed.
The o-rings may be leaking.
Someone in Answers suggested aiming a propane torch at the manifolds around the carbs & engine (not lit of course).
If there were a leak, the vacuum of the engine would suck in the propane and change the idle.

Answer 5

Check the simple stuff first..

You should have a little bit of slack on the throttle.....so up to a quarter inch of twist on the throttle without any movement of the carbs.

Adjust the idle adjustment screw - if there is one ?

Check the air/fuel mixture adjustment screw - again is there one on this bike ?

Check for leaks, holes, worn o-rings or gaskets.

Check your choke cable and make sure the choke is not permanently on !!

Hope you get it fixed.

Er.

Answer 6

Adjust your carb. That's all I can say. Flush the system. Mhm. Since you cleaned the carb, you MIGHT of knocked something out of balance. Just try screwing with it a bit. Your timing might be off too.

Answer 7

probably got the cable routed to tight, easy mistake to make. dont let anybody down you choice of bikes, the virago has a bulletproof motor. they always go over 100,000 miles before needing an overhaul.

Answer 8

Possibly air getting in,3000 is a bit high.

Answer 9

Most above is good advice but it could also be rich with a vacuum leak. frie it up and use carb cleaner around the carbs and cyl.head.If it starts to slow its a vacuum leak.IF it stalls its a bad leak.

Answer 10

WHEN YOUR CARB WAS OVERHAULED, MAYBE THE IDLE SOLENOID VALVE WAS RE ADJUST AND OR DILUTED! YOUR CABLE IS ONE THING... MAYBE IT WAS THEN PULLED AND NOT LUBRICATED ENOUGH TO GO BACK TO ITS NORMAL SPEEED! 3000 RPM IN A N IDLE SPEED IS REALLY HIGH FOR THAT CASE.... MAYBE YOUR MECHANIC ADJUSTED IT DURING OVERHAUL...