running rough cold

[blackdawg]

Well the carbs are synch finally idles around 1000-1050 by the tach.air fuel mixture needles are 1 and half turns out.idles great when its warm.Runs great no hestitation,the only problem is first starting the bike.Pull the choke full out ,start it idles fine then two minutes later the idle drops of and then the bike quits.Go out to restart same thing again.any ideas.

BLACKDAWG

[mro]

My 79 special likes to start on full choke, after about 20 seconds needs to go to half for another minute and then is good to go.

My 80 standard likes full choke to start and is good to go after just 10/15 seconds, go to half when at end of block and off at the stop light (about 1/4 mile.

As soon as you start it, check header. Are all four getting hot?


mro

[jms]

my 82XJ likes full choke and after a few seconds (when it starts to jump up to 2-3k I back it off to half and after it gets warm I back it off completely, Idles just over 1K. I do get a battery warning indicator when it first starts cold but it goes away after a couple seconds.

[blackdawg]

running rough

so what would be the cause and the fix.

[DiverRay]

You DO NOT let the bike idle for more than one minute!!! Either ride it, or shut it down!!
This is an AIR COOLED bike, and with NO AIRFLOW, it WILL overheat quickly!
Start it on full choke, after 30 seconds reduce to 1/2, and ride away. Works every time.

[skeggo]

Curious, do you shut your bike off at long stoplights?

[firecrackerboom]

i dont. but i dont know anything :P

[Crazcnuk]

Even air cooled engines won't overheat in a minute, but I suspect he was being generous when he said he lets it idle that long, most of us have a tough time sitting for 10 seconds!

Every vehicle behaves differently when cold, It's just one of the quirks you have to get used to with manual chokes and carbs.

My Virago likes choke off the start, unless it's over 80, first start of the day only. I just ride away, and about a block up the road I can turn the choke off.

The Shadow had to have choke to start in the morning, and it would start to run funny down the road, 3-4 blocks, letting me know to turn the choke off.

[DiverRay]

No, I run them!!
Really, I just don't see any need to idle the engine more than one minute in the morning. After that, it probably WON'T run properly on full choke. Once everything starts to hit, you don't need the raw fuel to keep it running. If you want to idle for a few minutes in the morning, just put it on 1/2 choke and then walk away.

[Crazcnuk]

I assume his won't necessarily idle at half choke.

Basically, you put the choke on start it, and as the revs climb take the choke off in steps.

I don't see the need to idle for too long either, but sometimes you have to run back in the house for something, or whatever, and just wanted to point out that it won't hurt the engine if it idles for a few minutes.

Biggest problem is, that if the choke is on when you leave it, you'll come out and find it 'idling' at 3000rpm!!!

[blackdawg]

running rough cold

I'LL just do that start when i come out in the morning.I was starting it and going back inside and no not letting rev 3000 rpm.

[Crazcnuk]

Heh, didn't mean to make it sound like you would, but I have done it a few times!

[GtrMn]

then two minutes later the idle drops

Sounds to me like it's fouling the plugs after that much time....

On a warm day mine 'll start with no choke. Even on a cold day 1/2 choke usually works. Only need to keep it on 30 seconds or so.

Oh yeah and my idle screws are turned out over 2 turns now...runs like a champ!
YMMV

[blackdawg]

running rough cold

maybe i'll try that turn the idle screwws 2 turns ,right now it 1 and half turns.My bike runs great it just need that cold start tweaking.When the carbs wereen't synch it use to run on full choke in the morning.I would let it warm up while i got on my gear and then shut the choke off.



BLACKDAWG

[GtrMn]

Check out the maintenance section under carbs. Ken's got the method down for the pilot circuit. I do it the same way...works everytime. I've used a colortune also but still like the "ear" method better.