Idle problems...

I have an 84 vf700f interceptor and the idle jumps up out of nowhere sometimes. It usually happens after the bike is warmed up. When I am cruising around for a while and I come to a stoplight the idle likes to jump to 3000 rpm? Sometimes it does it only a few times on a cruise and sometimes it does it every time. anyone have any ideas on what it could be? Any help would be much appreciated. Thanks

 

WHAT this is is: one cylinder cutting in and out.

YOU may have carbs that are clogged. TRY using a fuel system cleaner like SeaFoam and see if things improve.


ANOTHER possible cause is a cylinder missfiring occasionally, and the first thing to do is inspect the sparkplugs.....

YOU can find out which is the lazy cylinder by touching the exhaust headers about 30 seconds after the bike is first started....when that lazy cylinder cuts in it boosts the idle speed!

 

Could also be a bad carb sync.

 

Could be loose manifolds. Sucking air at times, going leaner = higher revs. Try tightening the bands around the carbs and heads. Or all of the above.

 

I plan on doing all of the above in the next week or so. Where do you guys suggest buying the manifold boots? I am pretty sure they are rock hard and if I am going to get in there to tighten them, I figure I might as well replace them. Also any places online to buy the liquid carb sync tool or should I just use the vacuum guage style? Anyone had luck with one more than the other? The vacuum guage style non liquid is more economical for me but if it works just as well I figure i would just buy that kind. Any further input would be much appreciated. Thanks!

 

man boots and ck rubber on the slides in carbs if they have a tear or not seated properly it will jump idle up

 

Here's one site with better prices:
CheapCycleParts.com's Honda Street Bike Parts Finder

I'm putting manifolds on mine now that I bought 3 years ago. My clamps were all the way tight. Manifolds are as hard as a brick. Take a look below. They would leak at times. Here's what I use for gauges. They work good, specially for free. Just doing a little maintenance.

 

I have the exact same problem on my 85 vf700f. I just live with it for now, other stuff to work on first.

 

and where the hell can I find seafoam? everyone keeps swearing by it but every cycle shop I ask looks at me like I am talking bout something for a boat. After its been recomended so many times by squirrel and the others I reall want to try it out, is it somethng to order online? Sorry to hijack your thread, just seemed like something we should both try even if its just for GP.

 

auto zone, checker auto, Orielleys' all teh auto places should carry it