Topic: Idle Issue.... speeding up

[luke000]

I just picked up this bike it would not fire on two cylinders, that was fixed by plugging in a wire going to a coil, now the bike is firing on all 4 but when it idles @ about 1000 RPM then if I blip the throttle it speeds up to 3000 then wont go back down until I put load on the engine like putting it in gear and lightly releasing the throttle then it will stay at 1000 RPM for a while any idea what's going on? Also the engine will be at 1000 and will rev to 3000 on its own without me touching the throttle.  I have two videos that might help explain what I'm talking about.  I don't think its the cables because the throttle returns fast and crisp.   

The videos are on      youtube .com / watch?v=WM2gDRjVAok&feature=youtu.be      and     youtube .com / watch?v=-G2pDbHoAvs&feature=youtu.be

[Stev-o]

Are you setting theidle when the motor is warmed up?  I like mine to idle a little at about 1500.

[FuZZie]

You have any idea how long it sat before you got it started?
Could have some gummed up carbs maybe

[Gordon]

What you are describing is a classic symptom of either unbalanced carbs and/or an intake leak.  To check for an intake leak spray some carb cleaner around the intake boots while the engine is running and listen for a change in idle speed.  To check for carb balance you'll need to hook up a 4-carb manometer. 

[grcamna2]

 +1 on what Gordon said.

[70CB750]

I had similar problems due to throttle cable routing.

I would check carb slides, throttle cable, throttle handle - just to make sure it all closes up the way it should.

What year?

[dave500]

ok,,you just got this this bike,,go over the ignition entirely before you tamper with the carbs,,,entirely,,,if it has the points system still in it it WILL need to be gone over fully,,dont tamper with the carbs at all untill you have your igniton sorted fully,in the faq on this site you will find points setting etc,use the search function,you might need to buy some small tools,dont frigg with the carbs untill you have the ignition sorted,fully and properly,if you dont get your ignition spot on first you will do carbs over and over,,too many people jump straight to the carbs as the problem,the most hardest thing to remove dissemble and vacuum balance,,when most of the time the ignition is the culprit,check your air filter,see how it runs removed?,,but get that ignition spot on first  before your tempted to pull carbs.

[grcamna2]

I agree w/ Dave500 on that; the advancer unit can have problems & keep your idle too high...sometimes they get dry on high temp grease where the pivot is & freeze up or the springs get stretched out & they stay too advanced.

[BobbyR]

Dave is correct. The key to getting these bikes to run well is a point by point exercise. You sort out each system and get it optimized. Then you get to the carbs and intakes. Not everything is carb synch, nor is everything ignition. It is a group of subsystems each one doing it;s job.

[phil71]

hit it with a hammer.

[dave500]

when in trouble or in doubt,,get a bigger hammer out?

[phil71]

There's a page in the shop manual for the 1960 thunderbird for troubleshooting poor radio reception. It says, word-for-word, "reach under dashboard and locate receiver unit. Jar receiver with the hand".
The FORD SHOP MANUAL actually says "hit the radio with your hand." Amazing.

[70CB750]

Russian computers had a hammer as part of the service kit. It was supposed to reseat  lamps by hammering on the case.

[bollingball]

I agree allways start with a complete 3000 mile tune up by the book in order carbs last If you don't know the history put in a new air filter it may look good but with age the paper does break down.

                     Ken