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Author Topic: Idling high  (Read 1350 times)

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Offline SurfinBird

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Idling high
« on: December 09, 2011, 09:02:50 AM »
78' 750F

I haven't really ridden the bike in a a couple weeks. I did a valve adjustment, filled and charged the battery and filled up the tank. It runs great, but, about half way through my ride to work (about 12 miles) I stopped at a light and it idled at about 3500 and rose to about 4000. I checked the throttle, not stuck and i've never touched the idle screw. Any thoughts?

Just a note, i've never had the carbs synced and have typically had to keep the throttle on a bit at stops.

A side question, what is it about letting a bike sit that cause problems pop up? It is put away running fine and comes out with issues.
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Offline AbbyRider

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Re: Idling high
« Reply #1 on: December 09, 2011, 09:09:53 AM »
Carb boot leak would be my first guess
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Offline luap

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Re: Idling high
« Reply #2 on: December 09, 2011, 09:24:28 AM »
is fuel getting to all the carbs ?
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Offline flybox1

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Re: Idling high
« Reply #3 on: December 09, 2011, 09:44:37 AM »
ONLY a valve adjustment? 
what about the rest of the regular maintenance?
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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline SurfinBird

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Re: Idling high
« Reply #4 on: December 09, 2011, 09:48:38 AM »
Long story, but I had a valve I needed to adjust (tappet was stripped so I couldn't adjust it with the rest) and i finally got to it.

Boots look good, fuel is getting to the carbs, all 4 exhaust feel about the same temp (it's still warm, from the ride in). When I started it up it idled at about 1200.
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Offline stinkfinger

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Re: Idling high
« Reply #5 on: December 09, 2011, 09:59:48 AM »
Carb synch'n shld be last.
Get the bike running ~great with
carb cleaning/setting/boots leaks/plugs/valves...etc
and then worry about the synch`n(fine tuning)
They shldnt be too far off from each other unless its reall been messed with.

Tony
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Offline flybox1

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Re: Idling high
« Reply #6 on: December 09, 2011, 10:54:27 AM »
Time for a good carb douching. Check for a hanging slide due to sitting/varnish.  (good snap closed with your return spring) and run some seafoam in your tank
If all looks good and you're confident your valves are correct, set your timing, and then head  to a vacuum sync of your carbs.

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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"
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