throttle problem - cable too short?

[mikew5th]

i just recently got my 1st motor bike going
everything was working just great on it.
i had to get a new throttle cable however. once i put on and attached the new cable, the bike just revs way too high, and turning the throttle grip doesn't do anything.
i did do some reading before just posting this, and i'm pretty sure there isn't an air leak anywhere (it was fine before the new throttle cable) but i replaced the gas line to the carb to make sure that was nice and tight, made sure everything was screwed on tight - still no difference

i'm not sure (thats why i'm posting) but i think it may be that the cable i got is too short?
the parts where you adjust it on the throttle handle, and where it attaches to the carb are all the way down, so i can't get any more slack that way
i attached a pic of what it looks like when the throttle is normal - should it be extended longer than whats shown? i can turn it about a 1/8th of a turn (is that normal - or should it go more?) - attached pics of the normal position, and turned as much as i can

i'm using a regular 2 stroke motor btw, i attached a pic of the bike too so you can see what i'm working with
thanks in advance!
-Mike

 

[Al.Fisherman]

If this just started since you replaced the cable, then there could be one of two causes (maybe both) that I'd first look at.
1. Cable too short.
2. Leak on the top of the carb where the cable fits through.

Remove the air filter, and watch the carb slide to make sure it closes as you rotate the throttle..

 

[Venice Motor Bikes]

There is a slot in the side of the slider thay fits into a small tab inside the carb to keep the slider in straight. Check that.

 

[Pinoyxprss]

Go with what venice said...I had that problem before and all it was is I didn't align the slider and it was binded at full throttle.

also check your adjustment screws on the throttle side and the carb side, set them all the way in and start adjusting them when you get the mottor started.

Have fun
JD

 

[DuctTapedGoat]

I bet your cable is stuck, but I still agree that you should check the slide barrel in the carb.

You have 3 throttle cable tension adjustment screws - two coming out of the throttle grip, and the one on top of the carb. Go until you get tension, check it often when you're setting it. From there, adjust your idle with the idler screw.

 

[mikew5th]

hey guys, thanks for the advice!
the cable is running inside the throttle return spring
the cable slides through its housing just fine
the slider barrel is aligned correctly, and the cable tension adjustments are already all the way in, so i can't get any more that way
also the idle screw is all the way out, so its not that either

i think al.fisherman had the right idea - to take off the air filter and look in that way, so that's what i did - i attached a picture so you can see that it doesn't go down all the way.

i also attached a couple pictures showing how i have the cable on the throttle grip, and how far it lets the cable extend (not long enough)

so unless i have that attached wrong, i think that my cable is too short.
where do i go from here?
thanks again!
-Mike

 

[Al.Fisherman]

MAKE a new cable customized to your own length. Any heat that will melt solder will do fine.
1. Remove existing cable.
2. Set both adjustments midway.
3. Install a longer cable housing (removed the cable itself).
4. Measure the housing length needed, and cut.
5. Insert cable in housing, install end cap, and measure to desired length.
6. Mark cable.
7. Wrap some small single strand copper wire at mark, do not cut off excess at this time.
8. Solder the copper to the cable.
9. Now you can cut off excess. I use a kelin pliers, and set on a vice and strike with a hammer...clean cut. Clutch cables I melt excess off and the cable won't fray.
10. Sand, or file solder point so the cable can go into the carburetor cap and fit into the slide of the carburetor piston.

 

[Al.Fisherman]

Look what I've found....

http://www.youtube.com/watch?v=0y27QZOCl50&feature=player_detailpage

 

[mikew5th]

well thanks for the all the help
but, i've never used a blowtorch before, and dont have one, or copper wire, or flux, or silver solder, i would also have to buy a new cable

so this is what i did:
i put the carb all back together, making sure the slider barrel went all the way down, with the other end of the cable unattatched
i then put the throttle handle in the part it rotates in(the part with the kill switch) to see how much more space i needed
then i drew a line on it to show the excess
finally - used a dremel tool to grind away the unwanted area

i still dont get why the cable was short, i mean the cable/housing was made specifically for these engines

oh well, what i did worked out, and the bike works normally again

i attatched a couple pictures so you can see what i did, hopefully if any one else has this problem, they'll find this thread
thanks again!
-mike

 

[Fast eddiee]

I am having the exact same problem, I switched out handlebars and
now my engine is revving high at idle. I popped open the air filter
and my carb slide looks exactly the same.

 

[Fast eddiee]

Wow, great idea, I am going to give that a shot, thanks.

 

[KCvale]

Ohh for heavens sake.
Pull the top of the carb and pull the cable out of it.
Now unscrew the cable housing bolt, remove the locking nut then screw it back in all the way down.

If that is not enough then screw the angle piece coming out of the throttle all the way in, past it's set nut as well if needed.

And if that is still not enough then check the cable connecter at the throttle at the end of the angle piece with a set nut is all the way in, that will give you all the cable you need.

Cutting the cable, blow torch, come on guys there are 3 frigg'n cable length adjusters in that system, enough to make an CNS carb throttle fit an NT and visa versa.

 

[crassius]

Pull the top of the carb and pull the cable out of it. Now unscrew the cable housing bolt, remove the locking nut then screw it back in all the way down.

I've seen this cause the slide to stop before opening all the way.

 

[KCvale]

I've seen this cause the slide to stop before opening all the way.

The throttle not opening all the way is not because the the cable fitting is too far in, the barrel is hollow, that is from too much slack in the cable.

With the idle screw where you want it there are 2 other cable adjusters in line to take the slack out.
Adjust them until there is just a pinch of slack in the throttle cable so you know the idle screw not the cable is setting idle and you'll have full throttle.

 

[Fast eddiee]

I followed Mikes advice from above, sliced about 1/4 inch off the plastic
piece, problem solved.

 

[wackypack]

Mikes advice - fantastic man thanks for taking the time to post, to add nice meaningful photos, and to this site for not yanking down this 12 year old post like most sites would! this worked perfectly on a Chinese 4-stroke where the cable was way too short even with all the adjustments turned in for more slack.