Cold start throttle

[Rasputin]

I am having an issue where my bike wont start cold without use of throttle. The enricher is on and I have to use a small amount of throttle or it absolutely wont fire. I have just completely gone thru the carbs and all passages are clear. Yup the Third time was the one that finally got everything clean. New jets, Floats at 25.4mm. I have colortuned and synched more than once just to be sure. Once it is running all seems to be perfect except if I drop the idle below 1000 rpm, then it dies. I set the idle to 1050 rpm and all is well except for the cold start. Any ideas? Too rich, too lean, float heights to high, or should I just twist my wrist to start it. My other bikes all start first turn with just the enricher on and use the same settings. Maybe I am worrying too much but I cant just take her out for a run to check her out with the ice and snow we have here. Thanks for any input

[dbeardslee]

When you colortuned it were you able to adjust through the entire range of color - yellow, bunson blue, and white/blue? On a cold start with mine when I pull the choke it starts and idles without touching the throttle. I had some issues with it not working properly about a year ago that I finally tracked down to plugged up filters on the vent tubes. I took them off and the problem went away. I had used some little lawn mower fuel filters on the ends of the vents, and they were the type with a paper element. That paper does not like moisture - it'll plug 'em up -, and they're made to be in a sealed system that isn't exposed to the air. My guess is they were absorbing moisture from the air until they became saturated enough to start causing problems - but that's just a guess. Could have sucked some in while it was raining too.

[Rasputin]

I can see the whole range of colors in every cylinder with the colortune. I have the vent tubes run to the stock airbox on this 78E that I am working on now. I have not checked that they are not kinked, but will check on that for sure. Thanks

[dbeardslee]

If all looks good there, you might want to take a look at the fuel bowls and make sure the enricher circuit is clear. JAT

[Rasputin]

I blew carb cleaner thru the passage in the fuel bowls. No problem there. I am thinking maybe my battery is a bit low and not turning it over fast enough as it has not been running for a while. I am not sure if that would cause this problem tho.

[dbeardslee]

If it'll fire with a little throttle I doubt the battery is causing the problem, but you never know. Another thing that made mine hard to start when I first got it was that it would foul plugs pretty quick. Might try pulling them and check their condition. If they're cruddy looking, hit them with a wire brush and blow them out good. If they look really bad you might try Ivan's trick - set them in a vice (or suitable substitute) with the 'gap' up. Heat them up with a propane torch until the ceramic insulator glows red (about 1 minute). That will clean all the contaminants off and keep them from immediately refouling. Clean plugs make a HUGE difference in how quickly they start. JAT

[Rasputin]

Godd thinking Dbeardslee. The plugs in it were definitely dark as it was running very rich before. I have a brand new set of iridiums here. I will get them in and see what that does for it. I was using the old ones until I got it running sweet and then was going to put them in. Mayhaps I should have thought of that sooner.

[dbeardslee]

Mine used to be so bad about fouling plugs that I carried a little wire brush in my tool kit. If it didn't want to start I could pull the plugs on the side of the road, give 'em a lick and a promise, and go on about my business. Finally got the carbs dialed in right, and it doesn't do it anymore. I also found during that process that the thing that seems to have the most impact on plug fouling is float height. Let's hope the plugs are what was causing the problem on yours. The nice thing about the iridiums is that they're as close to a foul-proof plug as you're going to get. They're particularly nice with hot coils.

[Ivan]

My first thought was that your idle speed might be too slow. What does the bike idle at when warm and no choke? Should be about 1100 rpm. Mine will idle at about 600, but it is very hard to start and won't idle cold with the choke on.

Also, the ceramic doesn't ever glow, but the black will burn off. The electrode will glow though.

[dbeardslee]

the ceramic doesn't ever glow

I get it to turn red. Are we talking about the same thing - the little ceramic insulator that goes around the electrode?

[Rasputin]

I put in the new iridium plugs, they show me I am a bit too rich. It did not help with the cold start. New plugs came out a medium/dark brown. I tried to clean up the old plugs but all they did was turn a medium brown. The electrode got red hot but not the insulator. Do I need to use a hotter flame? Will it burn off to close to white or is medium brown the best I can hope for? I want to keep the iridiums in great shape for when I get done monkeying around. The Idle is set at 1050-1100 range. I am going to rerun the colortune and see if I can improve on it but that wont happen until tomorrow night. I sure would like to have me some clean plugs to do a final check. Thanks guys.

[oldyam80sg]

Running NGK plug BP6ES.Today the weather was like 28 outside and the wind was bitter cold.Took the bike out today and turned on fuel,pulled out choke and hit start button.Thought it might give me a hard time since i use 20W50 oil.No problem-started right up without throttle.

[Ivan]

I get it to turn red. Are we talking about the same thing - the little ceramic insulator that goes around the electrode?

Yeah, I have never had the ceramic glow. It just turns white. You must have a badass torch.

[SFerinTEXAS]

Dont rule out the battery. Had a similar issue last year and didnt even consider the battery. Pulled the carbs suspecting trash had gotten in the pilot jets, Nope, clean as a whistle. Bench reset floats and proceeded to carb sync when it started like it was running on only 2 cylinders .one from each coil.

Long story short I had just had the battery out a few weeks before and added water so didnt think it had anything to do with this till I pulled it back out and found water level below the cells again. Being over 2 years old went ahead and replaced it . All that carb work for nothing.

Remember these bikes dont charge at idle and will not idle right with a battery issue.

[oldyam80sg]

I have seen people add too much water and it freezes.Very bad for the plastic battery case.