throttle stuck closed

Posted this in general, too, but realized I should probably ask the experts...

So I took my YZ400 up some logging roads. About 20 mins into the ride, I'm coming down a hill, I left off the gas coming around a corner, and when I go to open the throttle up coming out of the corner, the throttle sticks and won't turn. The bike dies on me. It won't restart for a bit, but I finally get it to fire up...after sitting for a few, the throttle had loosened back up, but as soon as it's fired up, I get about 20 feet down the road and it does it to me again. I finally managed to get the thing home threw it in the garage, haven't had time to deal with it lately...anyways, I start it up last night, same deal, kick start it no problem, go to twist the throttle and it barely lets me twist it, maybe a 1/2 inch, and it just hits a hard spot and won't twist any further. Anybody know what this might be? The engine starts and idles just fine, but I can't get the damned throttle to move...and no, there's not a rock stuck up in grip!

Could be a bad or dirty cable. You may also have some debris that the slide is catching on.

I would disconnect the cable from the throttle grip and pull on it. If it is hard to pull try some cable lube. If that doesn't fix it, I would pull the carb and clean it well. While you have the carb off, make sure that the cam doohickeys the cables go into are working properly.

The chances are it's the cable. Dirty or frayed.


and no, there's not a rock stuck up in grip!

I was going to say to check that :applause:

Sounds like a bad cable to me... lucky its sticking closed and not wide open throttle, better fix it before next ride.

another vote for frayed cable here...

I've heard of it happening to several different people on this board.

They have a cool tool to lube cables up with. You put it on the edge of the cable screw it tight then it has a hole on the tool that you squirt the lube in. It works well and prevents all the mess....I think when i bought mine it was like 5 dollars...

Thanks for the advice guys, I'm going to check it out this weekend.

Just in case anybody happens to have the same problem, here was the cause:

There is a small screw tucked in behind the throttle linkage. The screw must've come loose from vibration. It had backed itself out a little bit, and it was just enough to block the linkage closed. If I pulled hard enough on the throttle, it would scrape over the screw and allow the throttle to open up. The screw just happens to be in the (not-so) perfect place that if it backs out, it hits against the backside of the linkage just as you start to turn the throttle, only allowing you to turn the throttle about 1/4 inch before it jams up. Luckily, it's pretty easy to fix, although the screw is difficult to get at. Just take the throttle linkage cover off and you'll see the small screw tucked in behind the linkage. Use whatever little tool you can to tighten it up and you're good to go. If I continue to have issues with this, I'll probably lock-tite the thing in their, but I think it should be good to go without. Thanks for all the advice fellas.

Glad you got 'er fixed!


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