Hesitation when giving Gas

[Derk]

HI all, I have a 1974, that is running and starting great. only little problem when I come to a stop signal, I have hesitation when giving gas. just 1 sec. until the next stop. Plugs are new, carbs rebuilt, gas tank rebuilt, new ignition. Anyone has an idea.

 

[brettp]

What is your idle set at?

 

[Derk]

Night over 2000

 

[brettp]

I wonder if you have a jet with some crap stuck in it. You might also want to check your timing.

 

[drgnrdr750]

Are the carbs synced?

 

[brettp]

Are the carbs synced?

Great question. I have a DOHC so my mind goes to accelerator pumps in this situation. Carb sync makes perfect sense if no accelerator pump.

 

[Derk]

I wonder if you have a jet with some crap stuck in it. You might also want to check your timing.

Hi thanks for your reply, I will check next time I stop @ my mechanic. And that will be next year now. Bike is in for the winter.

 

[Qaxe]

Derk, are you talking about the flake sunrise orange K4 in your avatar with stock HM 4-into-4 pipes and carburetors? If so, then when the bike is warm, then it should idle closer to 1000rpm. 1200rpm max. 2000rpm is high for this bike.

 

[Derk]

Derk, are you talking about the flake sunrise orange K4 in your avatar with stock HM 4-into-4 pipes and carburetors? If so, then when the bike is warm, then it should idle closer to 1000rpm. 1200rpm max. 2000rpm is high for this bike.

Qaxe, Yes indeed it is the bike. Thing is , when I lower idle with warm engine. It will not be enought when engine is cold. After 15 min rides idle is always going up my */- 1000 rpm. Thus I will try to fix idle with warm engine and let you know the results. Thanks

 

[brettp]

Sounds to me like you need to let the engine warm up longer. Then when you and the bike are ready to ride the idle will be right where it needs to be.

 

[Qaxe]

Derk, these old geezers need babysitting.
Here's my regimen for starting out. I start the bike cold with a little choke and tend the throttle until I get my throttle stop screw where it needs to be to hold it at about 2 grand. (Easier on K4, because the throttle lock screw is on the left) I idle at 2 grand until it's warm. While it's warming up is when I get my gear all set, and get ready to go. Whether she gets warm in the driveway or up the road, whenever the bike is warm and the idle climbs (as it does) I back off the throttle stop screw.

I have done that every time on all my pre-78 CB750s since 19... except in summer time when it's actually warm. It's second nature now.

(I saw your bike, and shot right back to 1999. Great bike that 74'. Miss that orange.)

 

[Derk]

Hi All,
Idle is now @ 1200 warm bike , and problem is solved, thanks for the help.
Derk