Topic: Trouble running untill warm

[Brentadour]

My CB550 has a problem staying on untill its warmed up. After its warm, it'll run its ass off. I tried adjusting the air fuel screw, but it didn't help. What do you guys think?

-Brent

[TwoTired]

Which 550?  The stocker or the hybrid?

[rob]

Hello,

This may not be the solution to your problem, but maybe worth checking.  My bike, '81 CB 650 Custom, was having trouble starting somtimes, no matter what choke setting.  I finally figured it out, even though the engine kill switch was set to 'On', it wasn't quite there, and had an intermitent connection, and so it wouldn't start.  Now, when I want to turn my bike on, I jiggle that switch a little bit, and make sure that its right in the middle, and it starts up everytime.

Rob

[stanghater]

i think thats just the way 20+ year old bikes run

[bryanj]

If its the 77/78 thats just the way they are and none of the 500/550 will idle cold if you set the idle up hot!

[Zeke]

I always have the choke partially on while I'm riding to the freeway -- takes at least 5-10 minutes to get there.

If you try to turn off the choke any sooner it'll die.

Zeke

[Brentadour]

Bryanj, Are you saying to adjust the idle cold? Woundn't that make the RPMs scream when it warms up? Or do you just turn it down when the bike warms up?
-Brent

[eldar]

I dont have any exp with the 550 but with my 78 750k, I need choke for about 1 maybe 2 min and then thats it. Sure it may not be FULLY warmed up but a lttle easy gas and I have no problems. But then I am sure I have different carbs so that may make all the difference.

[oldbiker]

The idle setting should be done with the engine fully warmed up. When starting from cold use full choke and then gradually reduce the choke setting a bit at a time over the first couple of minutes riding.

[Chris Liston]

My 76 550 starts 99% of the time with 1/4 open choke.  Never needs more than than mostly.  Then I just modulate the throttle around 2k for about a minute or 2 and then its usually good.  Its usually the same when its cold out or hot out.  Only diff is the amount of time I have to play with the trottle.

[MetalHead550]

Brentadour,  what year is your bike?  The 77 78 models are set up so that when you set the choke, it pulls the throttle a bit too, to automatically increase the idle speed.  The 74 75 (dont know about 76) do not have this feature so you must hold the throttle open manually to increase the idle durring warm up.  Dont crack the throttle wide open obviously, but about 1/8th when starting, then maintain about 1500-2000 rpm till she idles on her own.  You sure everythings up to spec on the bike?  Later.

[bryanj]

Brent, No i was saying when you sent the idle hot, which is as you should do it, there is no way it will tickover when cold and you shouldnt expect it to.

[DrMark]

My 1978 CB550 is exactly the same way...rough idle til warm...then runs great...your right about the throttle opening some with the choke...