Topic: Cold Idle Normalcy?

[Lostboy Steve]

Since my build (77 cb550k) this bike won't idle well until warm. If you stand next to it and keep it from dying it will be fine. I tried adjusting cold idle and regular idle, but it seems as though until its at operating temp it won't keep a steady idle. Once warm it evens out perfectly. It doesnt bother me so much because other than that its 100% better than perfect. Carb settings are factory as are the idle jets. I only jumped the main jets up slightly to make room for the 4-2 exhaust. Also starting is perfect. It barely takes one kick or a blast of the button. Is this normal? Should I even care since it runs and performs so well? Thanks

[flybox1]

when you say 'cold idle' are you referring to a fast idle cam on your carbs?

your 'regular' idle should never need adjustment once its set after your bike gets to normal operating temps...

[uksparky]

I have the same problem, just got the bike last weekend...78 cb550 four...one of the POs put pods/electronic ignition and Mac 4 to 1 exhaust...I made idle mixture adjustment 1/1/8th turns out...idle 1,200..I read it a bad idea to fit the pods and 4x1 exhaust it un balances the carbs....will stall cold, have to keep choke out a few mins...still has rough idle hot

[lucky]

All motorcycle and cars from this time period did not idle unattended until warmed up.

When "automatic chokes" came into vogue then they were better but the first automatic chokes were problamatic too.
Matter of fact they were so problamatic many peolple put a manual choke back on, so they could have control of the thing.

Then came hot water chokes,fast idle cams etc.,.

Then came fuel injection except in the beginning the engine had to idle at 1500 rpm or the injectors would not work.

Now days you just turn the key and it idles right. That took about 40 years.

[kghost]

I have one of each. 350 to 750.

They all idle cold, just not well. Lol

[iron_worker]

If it's dead cold then it will likely need some attention to the throttle to keep it idling. I think that's normal. Shouldn't take too long to get enough heat in the engine to allow it idle on it's on though (like a minute or 2).

Although since you have the PD carbs then you should be able to adjust your fast idle cam to get a higher idle with the choke on I believe. Not super familiar with the PD carbs personally though.

IW

[Lostboy Steve]

All motorcycle and cars from this time period did not idle unattended until warmed up.

When "automatic chokes" came into vogue then they were better but the first automatic chokes were problamatic too.
Matter of fact they were so problamatic many peolple put a manual choke back on, so they could have control of the thing.

Then came hot water chokes,fast idle cams etc.,.

Then came fuel injection except in the beginning the engine had to idle at 1500 rpm or the injectors would not work.

Now days you just turn the key and it idles right. That took about 40 years.

Thanks Lucky. Yeah I know the whole choke dilemma, didnt know how it worked with bikes. Have any experience with thermal wax for the Mazda Rotary lol. They really used wax that melted to adjust warm idle.

[Lostboy Steve]

If it's dead cold then it will likely need some attention to the throttle to keep it idling. I think that's normal. Shouldn't take too long to get enough heat in the engine to allow it idle on it's on though (like a minute or 2).

Although since you have the PD carbs then you should be able to adjust your fast idle cam to get a higher idle with the choke on I believe. Not super familiar with the PD carbs personally though.

IW

Yes, I am able to adjust the cold idle but its extremely unpredictable. I think you're right on, attention to throttle for the first few minutes is exactly what i have been doing.