Author Topic: Why does my bike have two idles?  (Read 964 times)

0 Members and 1 Guest are viewing this topic.

Offline dgilling

  • Hot Shot
  • ***
  • Posts: 343
Why does my bike have two idles?
« on: January 31, 2009, 03:54:37 PM »
When I pull up to a stop light to idle the bike will idle fairly high but some what normal, but when I hit the throttle quickly just right the idle will drop down much lower.  The bike will possible die if it's not warmed up enough and if the bike is really warmed up then the first idle will be too high.  The only thing I can think of is I don't have both the push and pull cables hooked up (just the pull).  I also don't remember this happening before I rebuilt the carbs.

Offline seaweb11

  • 1st Mate &
  • Really Old Timer ...
  • *******
  • Posts: 6,258
  • Ride & Smile
    • Playground Directory
Re: Why does my bike have two idles?
« Reply #1 on: January 31, 2009, 04:12:07 PM »
Sounds like it's just not pulling back all the way.

Lube cable again?

Offline MCRider

  • Such is the life of a
  • Really Old Timer ...
  • *******
  • Posts: 14,376
  • Today's Lesson: One good turn deserves another.
Re: Why does my bike have two idles?
« Reply #2 on: January 31, 2009, 04:15:57 PM »
When I pull up to a stop light to idle the bike will idle fairly high but some what normal, but when I hit the throttle quickly just right the idle will drop down much lower.  The bike will possible die if it's not warmed up enough and if the bike is really warmed up then the first idle will be too high.  The only thing I can think of is I don't have both the push and pull cables hooked up (just the pull).  I also don't remember this happening before I rebuilt the carbs.

What bike?  regardless, the B cable should be there only as a tag along. Your carbs should return smoothly and completely to idle without it. Something is hanging up, likely the A cable to begin with. If not, we'll need to know the model to discuss particulars.

Its not abnormal to have to set the idle up, or hold it up with the throttle, while it warms up. But once warm, everything should work properly.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline Gordon

  • Global Moderator
  • Really Old Timer ...
  • *****
  • Posts: 12,114
  • 750K1, 550K2
Re: Why does my bike have two idles?
« Reply #3 on: January 31, 2009, 04:18:39 PM »
This started happening after you rebuilt the carbs.  Did you vacuum synch them as the final step?

Offline Hush

  • Finally they realise that I am an
  • Really Old Timer ...
  • *******
  • Posts: 6,761
  • "Lady, I've heard it all before"!
Re: Why does my bike have two idles?
« Reply #4 on: January 31, 2009, 04:27:00 PM »
My guess is clogged cables making them hang up in there somewhere.
I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

Offline scunny

  • Old Timer
  • ******
  • Posts: 4,618
  • don't call me expert
Re: Why does my bike have two idles?
« Reply #5 on: January 31, 2009, 05:22:04 PM »
chech the routing of the cable as well, you don't want any kinks
past-cb100,ts250,cb500,cb500,gs1000,gs650g.phillips traveller
present-CB 650 retro
            VTR1000F3
           XL250S riverbed rocket
           TS250[sold]
           TS185[sold]
           XL125S[sold]
           MT50 (white)
           MT50 (red)[sold]
           KN250/XS400 project
           XR/XL250 bitsa under construction
           SL100[sold]
           XL250R
           pedal(pub bike) leaks oil
my gallery http://gallery.sohc4.net/members/personal/scunny

Offline dgilling

  • Hot Shot
  • ***
  • Posts: 343
Re: Why does my bike have two idles?
« Reply #6 on: January 31, 2009, 05:27:03 PM »
This forum is always so great at promptly feedback...thanks.

Its a 77 750.  I'll check the routing and give it some lube and see if that helps.  I have a really nice syncing guage and yes I synced them properly after the rebuild.

Offline MCRider

  • Such is the life of a
  • Really Old Timer ...
  • *******
  • Posts: 14,376
  • Today's Lesson: One good turn deserves another.
Re: Why does my bike have two idles?
« Reply #7 on: January 31, 2009, 05:30:40 PM »
This forum is always so great at promptly feedback...thanks.

Its a 77 750.  I'll check the routing and give it some lube and see if that helps.  I have a really nice syncing guage and yes I synced them properly after the rebuild.

When I was younger I always approached problems wrong, thinking that mine was something special. There were tens of thousands of your bike put on the road and the throttles all worked perfectly. Yours can to.  Don't get hung up on the B cable. It is a safety device not a functional necessity. Your throttles should work just like they did in 1977, smoothly and completely. Take it step by step.

I do lean towards the A cable being too tight at the adjuster at the twistgrip. Give it all the slop it has to give and see if it returns to idle. If so, got it. If not, its somwhere else.

If there is no slop to give then back off the adjuster on the bell crank. You should have a little room to adjust at both places.
« Last Edit: January 31, 2009, 05:33:17 PM by MCRider »
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."