« previous next »
Pages: [1]   Go Down

Author Topic: Idling high  (Read 1351 times)

0 Members and 1 Guest are viewing this topic.

Offline SurfinBird

  • Enthusiast
  • **
  • Posts: 194
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.
Logged

Offline AbbyRider

  • Hot Shot
  • ***
  • Posts: 252
Re: Idling high
« Reply #1 on: December 09, 2011, 09:09:53 AM »
Carb boot leak would be my first guess
Logged
'98 VTR1000 Superhawk
'78 CB750F
'77 CB750F (in the works)
'81 KZ650 sitting in pieces in my basement

Offline luap

  • LAWL
  • Expert
  • ****
  • Posts: 779
Re: Idling high
« Reply #2 on: December 09, 2011, 09:24:28 AM »
is fuel getting to all the carbs ?
Logged
75-550 ffsc sold, 78-550 diamonte sold, 125s grasshopper sold, 76-550 puma sold, 78-550 tracker sold, 74-550 verde diablo Sold, 74-550 Noemani finished trying to sell. 72 500 hartail in the works
www.cb-town.com
"I dont need a bike covered in paint an chrome I know exactally bout how big my coc( is"

Offline flybox1

  • My wife thinks I'm a
  • Really Old Timer ...
  • *******
  • Posts: 14,301
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?
Logged
'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

  • Enthusiast
  • **
  • Posts: 194
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.
Logged

Offline stinkfinger

  • Dirtbiker at heart
  • Full Member
  • *
  • Posts: 41
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
Logged
Dualsports are an all access
back-stage pass to nature.

Offline flybox1

  • My wife thinks I'm a
  • Really Old Timer ...
  • *******
  • Posts: 14,301
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.

Logged
'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…"
Pages: [1]   Go Up
« previous next »