4k idle when hot

[justin]

Hey, hope your summer has been awesome. My H1F will idle at 3500 to 4000 rpm when hot and takes awhile to cool off and idle normally. What's up?

Justin

[givr]

More information is required.

Is this a new condition?
Could be several things, carb sync, air leak, idle stops set high, stuck slide etc. Most likely carb related.

[justin]

Seems to be heat related. If I run to town at 60 (13 miles) it will idle high till the bike has sat for awhile. If the motor is just warm it idles at 13-1500 like it's supposed to. The idle was set after riding around the yard for a bit, not after a highway stint. Could that be some of it?

[givr]

A good carb clean and inspection is the first step.

I'd check for carb sync, a lean pilot circuit, and/or vacuum leak of some kind. Check the carb phenolic insulators for cracks and make sure it's a good seal. I've heard some use silicone to make sure it's sealed. Just a few suggestions.

[zambia]

Like Givr says, high idle usually means a lean condition, which can be bad if not corrected. Check carb inlets for good seal...search Biker Don's post for gluing your carbs on.

Z

[lc]

The phenolic spacers (between the carb spigot gaskets) have been known to crack. I'm wondering if the heat of the cylinder is opening a crack? Be sure there is some slack in all cables to the slides. Another possibility is the crank seal under the alternator rotor. If you find oil residue in the alternator case this too is a possibility. Either a slide(s) is being held open somehow or there is an air leak(s) causing the issue.

+1 on gluing the carbs on to their spigots too. (Watch that you don't plug the tiny pilot outlet passages at the intersection of the carb to spigot though)

J

[biker Don]

check the carb tops on all 3 cylinders too.
a loose one will bring up the idle.

use ultra copper exhaust silicone on the spiggots.
coat the whole spiggot thin except for an 1/8 inch
away from manifold opening. Do the slits in the carb mount.
Don't get it all over and dripping to alter the
air flow. Completely wipe off any on the phalic ;D
seal, leaving only the slits filled. Slide on the carb
and you should end up with a nice ring of
copper sealing things up bettter.