need a little help

[daves86vmax]

my friends 85 is having idle issues.it will idle then for no reason idle up to around 3000 rpm then eventually back down..and it doesnt idle well when it does idle.if the bikes off and u flip the throttle it snaps right back so i know its not binding but if its running and u flip the throttle it hesitates for a few seconds then comes back down slowly..does this seem like a intake manifold leak or a vacuum leak?

 

[Rhoy Carter]

That could be a number of things,vacuum leak, lean condition, pluggage in the carbs. I think I would pulls the carbs, check the mainfold boots and clean the carbs, then sync the carbs to start with.

 

[hubeerjw]

Sync was my first thought, but a leak may also be an issue. Get some starting fluid and once the bike has idled down start to spray around the intake boots and any vacuum lines and see if it idles up at all. Sometime you can get in a still garage and light up a cig and gently puff out a thick cloud of smoke around the intake and look for something funny. Or if you grab the "good" smokes... everything may look funny.

Jeff

 

[95spfldmax]

Sync was my first thought, but a leak may also be an issue. Get some starting fluid and once the bike has idled down start to spray around the intake boots and any vacuum lines and see if it idles up at all. Sometime you can get in a still garage and light up a cig and gently puff out a thick cloud of smoke around the intake and look for something funny. Or if you grab the "good" smokes... everything may look funny.

Jeff

+1

and

+++1

 

[[email protected]]

My guess would be lean condition caused by an air leak.

 

[daves86vmax]

ok.i think i'll pull the carbs and check around the intake.the boots are only a year old but i'll look anyhow.i'm afraid the guy that worked on it before he contacted me pulled off the intake manifold and didnt seat the o-rings correctly.i synced the carbs but it just wont stay at idle speed for long.thanks for the input guys its always helpful

 

[94 V-Max Rider]

my friends 85 is having idle issues.it will idle then for no reason idle up to around 3000 rpm then eventually back down..and it doesnt idle well when it does idle.if the bikes off and u flip the throttle it snaps right back so i know its not binding but if its running and u flip the throttle it hesitates for a few seconds then comes back down slowly..does this seem like a intake manifold leak or a vacuum leak?

I suspect an air leak. When the idle surges up, spray the intake manifolds with carburetor or brake cleaner. If the idle drops, that's the problem. Check the manifolds for dry-rotting and make sure the clamps are tight. Id also be interested in knowing if the the synchronization is anywhere near right. Time to start the process of elimination. If you don't have vacuum gauges, you'll have to do a bench synch. That will get you in the ballpark, but it's by no means accurate.

Incidentally, I had one where one of the throttle butterflies wasn't sitting in its bore properly (it wasn't closing as it should despite everything I tried while trying to do a bench synch). I finally decided to loosen the retaining screws slightly. Upon doing so, it fell right into place and closed. I re-tightened the screws and performed a final bench synch, and it ran fine. Damn thing was driving me nuts. Something worthwhile checking.

 

[daves86vmax]

turns out the air leak was the carb boots which is unfortunate because i replaced them for him about 2 years ago.he recently had someone else(a self proclaimed harley mechanic)check it out for something and he didnt seat the boots down correctly on the locating tabs and they were that way long enough that now when i seat them like they should be they wont seal.i also noticed the "harley mechanic" was using something to pry the boots away from the intakes and put a couple cuts in them and bent a few of the tabs on the intakes and put a few small gouges in the intakes also.ugghh...i feel bad for my buddy.