Mysterious RPM climb at stoplights....???

[Ghosttown]

Does anybody have an idea why my RPM's would slowly climb at stoplights on my 81' CM400e? ??? The only time it seems to do it is after it has been warmed up good, maybe after a good 5 miles. Once I come to a stop, my RPM's slowly rise, not sure how high they go no tach, but it's a lot higher than a normal idle. I've kinda gotten used to letting the clutch out slowy to bring it down, but that only works for a couple seconds, and I can only imagine the amount of wear it creates. My first thought is possibly the choke not fully opened? Might be time to get a new cable or tear into it. Any ideas would be appreciated.
Thanks.

 

[anarki650]

Check for vacuum leaks and or leaks at the carb holders. My kz was doing that exact same thing to me, turns out that once the engine got good and hot and the rubber carb holders started to expand they started to leak. She ran perfect cold, but every time she got heated up the rpm's started climbing at idle just like you described.

 

[Rocan]

also check cable routing...

honestly i think anarki650 has the answer...

spray the carbs with wd40 when you have the problem and see what happens to the revs

 

[Ghosttown]

Awesome. Thanks guys. I will check it out tomorrow after I get to work, she is nice and warmed up by then.
Much appreciated.

 

[Rocan]

Awesome. Thanks guys. I will check it out tomorrow after I get to work, she is nice and warmed up by then.
Much appreciated.

really? mines usually dead and beat up by then.



wait- are we talking still talking about the motorcycle?

 

[Ghosttown]

Well, this afternoon I soaked down the carbs with WD40 after it was good and warmed up, but I didn't really notice any change in RPM while it was running. I guess the next step will be to go over that area and make sure everything is tightened. I can't really spot any obvious vaccum leaks, but I haven't really torn into things yet either. It's too nice, gotta ride!
Thanks again guys.

 

[diesel450]

Too nice!!?? Where the hell are you? It's been raining up here in the North East for the last month. no shit, the last month!

 

[Ghosttown]

Too nice!!?? Where the hell are you? It's been raining up here in the North East for the last month. no shit, the last month!

Actually here in Wyoming we have been receiving quite a bit more moisture than usual too, which adds up to about 3" for the month of June, that's a lot for us. For the most part though, we have been in the 80's and sunny for the past couple weeks. Not to shabby.