Very high Idle

F

Fast eddiee

New Member
I have a motorized bicycle that idles super high, the further I pull
in the clutch, the faster the idle, it sounds like it might
blowd up sometimes.
I checked my throttle cable by removing the air cleaner,
it does not close the carb completely when cable relaxes.
The cable snaps back fine and opens completely,
Im thinking thats ok and maybe its a manifold gasket leak?
Not that experienced in Motorized bikes, anybody have a suggestion?
Thanks.
 
Fast eddiee said:
I have a motorized bicycle that idles super high, the further I pull
in the clutch, the faster the idle, it sounds like it might
blowd up sometimes.
I checked my throttle cable by removing the air cleaner,
it does not close the carb completely when cable relaxes.
The cable snaps back fine and opens completely,
Im thinking thats ok and maybe its a manifold gasket leak?
Not that experienced in Motorized bikes, anybody have a suggestion?
Thanks.
Click to expand...

You've got something wrong with your cable somewhere or carb, cause the barrel slide should be able to close the carb completely. The way the idle is set is the idle screw props open the slide a bit, sounds like yours is staying open on its own...

An air leak would also make you have a high idle, but if your slide is propped open thats your problem...

Perhaps your throttle isn't assembled properly? Or you were given the wrong throttle cable somehow? Or the adjustment on your throttle cable is adjusted all the way out? If you pull the cable out of the throttle and let it go the slide in the carb should go all the way closed, are you sure you have the slide installed in the carb in the proper orientation? You didn't say what kit or carb you have so its hard to be very specific, but there should be a slot down one side of the slide and that slot needs to go over a peg inside the carb, if they are mis-aligned the slide wont close properly. Or perhaps you have a burr inside the carb that prevents the slide from the full range of travel, or the slide is bent up or something?
It's a pretty simple mechanical thing here, the slide should be pushed all the way down to close by the spring and only be propped open slightly by the protruding idle screw, so you'll have to dig in and figure out what is keeping it propped open so far....
 
Ok, yea thats what im thinking, I bought the bike from somebody else,
I didnt assemble it myself. The throttle cable is adjusted down as far as
it can go and i still see a large gap in the slide when i release the throttle.
When I open up the throttle I can see the slide go up all the way.
The adjustment screw did nothing. I loosened it and it fell out
when i was riding.

I will try what you suggest. Thanks, ill report back later.
 
Fast eddiee said:
Ok, yea thats what im thinking, I bought the bike from somebody else,
I didnt assemble it myself. The throttle cable is adjusted down as far as
it can go and i still see a large gap in the slide when i release the throttle.
When I open up the throttle I can see the slide go up all the way.
The adjustment screw did nothing. I loosened it and it fell out
when i was riding.

I will try what you suggest. Thanks, ill report back later.
Click to expand...

My guess is the slide is just inserted into the carb improperly and not aligned with the pin. Take the top of the carb off (where the cable goes in) and the slide will come right out. Then note the slot in the slide and pin in the carb and put the slide back in the carb so they align properly and see if it closes all the way.
Once you have the slide in there properly and closing all the way you are going to wish you hadn't lost the idle screw! I'm guessing you can buy a replacement but if you have a grinder I don't see any reason you couldn't just get a screw that threads in the carb properly and use the grinder to round down the tip like the original idle screw....
 
Ok, makes sense, I am going to work on it tomorrow.
Thanks for the advice.
I saw some screws on line, i just want this ungodly Idling
to slow down, sounds like its going to explode.
 
Air (vacuum) leak is my guess. But it would help to know what engine and carburetor you have. It makes diagnosing problems much easier than assuming and guessing. Did it ever idle right or is this something that just started? You say you bought the bike. Did it idle right when you bought it?

Tom
 
Not sure, there are no markings on it.
I did change the handlebars out, I am going to mess with the throttle
cable this evening and see if i messed something up when i did the change.
I dojnt remember it idling this high when i first bought it.
 
Changing the bars means you had to remove the twist grip throttle assembly. Are the bars higher/wider than the originals? Is the cable too short now? Did you reinstall the throttle correctly? Now it starts to sound like you do have a cable tension issue.

Tom
 
It was the throttle cable, too short. The carb slide went all
the way down when I removed it from the throttle.
I have to get a new one. Must have been the handlebar
changeout . thanks all .shft..shft.for the advice
 
Fast eddiee said:
It was the throttle cable, too short. The carb slide went all
the way down when I removed it from the throttle.
I have to get a new one. Must have been the handlebar
changeout . thanks all .shft..shft.for the advice
Click to expand...

Ok, sounds like you nailed down the issue....

Did you check all the adjustments on that cable, at the throttle, at the carb, sometimes one in the cable, perhaps they are all just maxed out? Usually the cables are plenty long...

You can make your own throttle cable from a regular cable pretty easy if you have soldering equipment. Just wrap some thin solid wire (like telephone or solid cat5 wire) around the cable where you want the ball end (that goes in the barrel of the carb) and solder the wire in place on the cable. Presto, throttle cable....
 
Yep. Yea, it does seem like I should have enough cable, but im about 1/2"
short. Been messing with it, I dont know if I have to cut some
housing or what. Im a bit stumped.
 
That's kinda odd, but....
You've never identified the carb you are running unless I missed that? I've heard the throttle cable length is different on the NT style carbs and the CNS carb, perhaps you have a motor that has had the carb swapped CNS to NT but the throttle cable wasnt swapped? Hard to tell with the info you have given. A picture would help out here.....

If you do need a longer throttle cable do like I said, just get a brake cable that has the same size barrel end like the one that goes in your throttle, then on the other end (where the carb slide goes) just solder in place a piece of thin solid wire in the spot the ball end is supposed to be. Make it slightly long and you can adjust out some slack with the adjustments, if you end up too long you can just solder another ball end in place....
 
nightcruiser said:
That's kinda odd, but....
You've never identified the carb you are running unless I missed that? I've heard the throttle cable length is different on the NT style carbs and the CNS carb, perhaps you have a motor that has had the carb swapped CNS to NT but the throttle cable wasnt swapped? Hard to tell with the info you have given. A picture would help out here.....

If you do need a longer throttle cable do like I said, just get a brake cable that has the same size barrel end like the one that goes in your throttle, then on the other end (where the carb slide goes) just solder in place a piece of thin solid wire in the spot the ball end is supposed to be. Make it slightly long and you can adjust out some slack with the adjustments, if you end up too long you can just solder another ball end in place....
Click to expand...
1/16" I.D. brass tubing cut to about 3/32" length also can be used as the cable stop. You need to know how to solder with either suggestion.

Tom
 
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