Throttle cable sticking!

The throttle cable on my '82 Kawasaki KZ750H sticks when the engine is cold, and particularly when the choke is on. I have to kill the engine if I rev it up before it is warm. Jiggling the throttle won't drop it back. After it's warm enough to cut the choke, it seems better, but I don't trust it. The cable looks fine and is not kinked along it's length. I can't see why the choke setting effects this, but it does.

What is the easiest way to lube the cable? And where is the return spring (it might be weak)? Thanks!

Check the adjustment of the throttle and throttle return (assuming you have one) cables. If the adjustment is out of whack you can have similar problems.

Not sure why it would make a difference hot vs. cold though.

Just one cable. I'm guessing the return spring is either in the handle or near the carbs somewhere. The cable is adjusted fine; when warm, it opens the carbs fully and fully closes them as well. No, I don't know why the choke effects this, but it does. I'm thinking the cable is dry inside, as it is a bit sluggish (in feel) when cold.

Are these the original cables? If so you may want to try a bit of cable lube.

The return spring should be on the carbs, not in the throttle twist assembly. Usually the springs are pretty resilient.

Yep, original cable (just one). You mentioned "If so you may want to try a bit of cable lube."

Yea, that's what I was asking. How? I am assuming that you take the throttle apart at the handlebar and squirt the stuff down the cable...right?

Is the throttle return spring(s) at the carbs a single spring, or do all 4 carbs have one?

Don't use a spray lube unless you have the proper cable lubing tool for sprays. Without is really messy!

A cheap and effective alternative is to use a sandwich bag as a funnel. Once you have the end of the cable free from your throttle, poke it thru a corner of the bag then use an elastic to hold it tightly in place. Tape the bag to your bars, then fill it with some oil.

When the oil runs out the other end, you're done!

Cheers.

Sounds normal to me. When you use the choke the idle will rise. Have you tried to start the bike without the choke on or just partially on? Sometimes I dont even use the choke when cold.

Are you talking about when the bike is hot or cold or the outside temp? Grease in the twist grip gets old and starts to bind up, especially in cooler weather. Happened to me, removed, cleaned and regreased (lightly) and all is well!

As I mentioned in the original post, this only happens when the bike is cold and the choke is on. I realize that the engine will rev higher when the choke is on. that's not the problem. If I tweak the throttle during warm up for an instant, say up to 4000rpm, it stays at 4000rpm when I release the throttle. I then have to kill switch it to stop it. After that it's okay again until I tweak the throttle...problem repeats.

Once the engine has warmed up, and the choke is off, the problem is mostly gone.

polkat wrote:

As I mentioned in the original post, this only happens when the bike is cold and the choke is on. I realize that the engine will rev higher when the choke is on. that's not the problem. If I tweak the throttle during warm up for an instant, say up to 4000rpm, it stays at 4000rpm when I release the throttle. I then have to kill switch it to stop it. After that it's okay again until I tweak the throttle...problem repeats.

Once the engine has warmed up, and the choke is off, the problem is mostly gone.

what you just stated about adding throttle while on choke and a cold motor is typical of these bikes. not a cable issue.

I have found that the routing of the cables effects the throttle response. I would pop the gas tank off and move physically move the two cables on top of the rubber damper that holds the gas tank in place or uder and test the return.

I had a problem with the return when I swapped out handle bars and lubed the cables to no effect, not until I removed the tank the return operated as normal. The problem was a simple fix, but is almost too simple to even consider.

Hummm...doesn't sound right that the engine would stay at 5000rpm just because the choke is on. Also, people keep responding about two cables. This bike only has one and that is stock. But the suggestions are appreciated! I'll figure it out.