Bad throttle cable?

[YZThumper]

The bike in question is a 91 KTM 500. When I turn the bars to the left, my throttle surges. Of course the first thing to check is if the cable is mis-routed and thus binding on something. I checked and re-checked and I'm 100% sure the cable is routed properly and I can't see it binding on anything. I've cleaned the throttle body, tube, gave it all the free-play I could where the cable enters the carb, and lubed the cable . . . still surges when I turn the bars to the left. So in desperation, I actually take the throttle cable and route it directly to the carb outside the bike on the left side. All I have to do is push the cable in the middle a few inches and the throttle surges???
I have 2 observations: The manner in which the throttle cable works on this particular bike seems odd. 1) On all my other bikes, the throttle cable is anchored to both the throttle body and carb so the throttle cable can't pull away from where it enters the throttle body or carb. On this bike, the throttle cable ends just fit loosely into the carb and throttle body, so that I can actually pull the cable housing (rubber cover) away from the carb and throttle body. 2) The throttle cable actually seems too long. When the cable is routed properly and the bars are turned to the left, the cable begins to form an arch above the bars because of how long it is. When turned to the right (which lengthens the distance between the throttle body and carb) the throttle doesn't surge. Add dumb as this may sound, the extra length of cable seems to cause the throttle to surge when it's turned to the left.


Is it possible the previous owner used the wrong throttle cable on this bike, or is it possible the cable is frayed on the inside and hanging up when a small amount of pressure is applied to it?

 

[jmics19067]

here is a few things to check:
the outside wrapping of the cable is coming apart. If the spiraled core of the sheath breaks down an arc in the cable effectively lengthens the sheath and basicly shortens in the inside of the cable. Grab each end of the sheathing and give a slight tug if it acts like a spring toss it.

as you turn the bars and you get your arc make sure the arc isn,tcocking thebarrel of the cable out of the throttle assembly.

does seem awfully strange that if everything looks good it surged turning to the left compared to the right. even if you can't truly figure out whatthe problem is I would get a new OEM cable from KTM and give that a shot. If you dont have the manual take a good look at the parts book to make sure youdo have all the correct pieces while you are at the dealership.

 

[yzeater]

What happens if you take the assembly off the bike, and twist the throttle (bike on, in neutral)? If it sticks, it's not a routing problem

 

[cr25096er]

get another cable.