sputtering in cold weather...a lot

hey guys.....been a while since I posted here...but I been a member for quite a while. Anyway....still got my 81 440LTD....still ride it a lot. This morning....I was riding to work....it was about 30 deg out....I was low on gas...but not that low...had at least a gallon in the tank. after riding about 2 mi ok.....i started to head up a steep hil...and the bike began to sputter really bad in any gear....and with the choke in any position. It never stalled out....but I had to pull over cause it wouldn't go. I turned around to take it home and headed down the hill.....at the bottom of the hill I decided to keep going to get home.....I closed the choke the whole way like I would if it was warm.....and I made it home OK....I tried restarting it several times at home and it was OK.....checked the oil and it was not low....didn't smell bad....no bad exhaust smoke.

What do you guys think?.....low on gas and hit some moisture in the tank?.....had the choke open too long?....oil too thick?.....just too damn cold?

is it you or the bike that's sputtering in the cold weather seriously i would check the plugs you might have fouled them from running it to long on the choke [enrichner it actally add's extra fuel] throw in a fresh set of plugs and i bet it will fire right up. try it and let us know how it go'es.

If not already done, would also assure valve clearances are set to specs. Thinking too tight valves would be consistent with the symptoms presented.

low on gas and hit some moisture in the tank? Nope. Because fuel level would not prevent any moisture from settling to bottom, as gasoline floats on water.

had the choke open too long? Maybe. Could have possibly fuel-fouled a plug.

oil too thick? Don't think so, at least not after running two miles.

just too damn cold? Nope. Would require longer warm-up, but bike performance should actually benefit.

Would assure air filter is clean, and (if applicable) not over-oiled.

Good Luck!

I know my z1 i horribly cold blooded and dosent like to run right or idle for that matter until it has fully warmed up. But then again kawi 4's are nitoriously cold blooded. I remember one time i tried to take off in 1st gear before she was fully warmed up......it made a spit and pop and just died, i looked so stupid but luckly knowbody was around.

Patton wrote:

low on gas and hit some moisture in the tank? Nope. Because fuel level would not prevent any moisture from settling to bottom, as gasoline floats on water.

OK...I agree with all....but I am a little confused by this one......am I understanding that the only way you can have a moisture problem is if you run out of gas?.....

This may sound dumb...but I was just wondering if the tank being in an inclined position going up hill may have had something to do with the bad fuel hitting the carbs.....its just a wild ass guess....but after I turned around and went down hill....the problem went away for good......I took it out last night for a ride to get gas and had no problems....before or after the fillup.

wonder if you have some obstruction on the screens on the petcock, when it runs low, it doesnt get all the fuel needed

You have a real choke on your Keihin carbs. Running on choke too long can foul spark plugs. I would make sure the plugs are not fouled. Next, it does sound like a fuel issue but more likely the delivery of fuel to the carbs. I would completely drain the tank and refill. Sounds like bad gas; that is, water in the gas.

i say to check your float heights.
you said you were on a steep incling then it started to sputter.
you probally uncovered the mains and it was starving for fuel.
if it ran fine on a level surface but sputters going uphill, that is where i would check first.

On my 750, anything less than a gallon (before fuel light goes on) at the uphill outside my office, will have the same effect. Have you done any guess and check on hills with a full gas tank?

As many can attest, I am far from an expert, but if your petcock is like mine( I think we have the same gas tank/petcock setup) on an uphill with low fuel, the gasoline all situates real of the petcock, and you lose fuel pressure.
See if switching to reserve helps at all, this way you'll know if it is a low fuel issue before you go tearing into your carbs.

LP440 wrote:

Patton wrote:

low on gas and hit some moisture in the tank? Nope. Because fuel level would not prevent any moisture from settling to bottom, as gasoline floats on water.

OK...I agree with all....but I am a little confused by this one......am I understanding that the only way you can have a moisture problem is if you run out of gas?....

Regardless of fuel level inside tank, any water will sink to the bottom and pass on through the petcock.

The manual (non-vacuum) petcocks have a sediment bowl where any water is supposed to collect without going on through the fuel line toward the carbs. With sediment bowl fitted, routine maintenance includes unscrewing it and dumping it and cleaning the round fuel filter screen which sits atop the sediment bowl.

Imo, the tank fuel level alone (high or low) is immaterial to volume or "pressure" of fuel flow from the tank (provided the cap vent is functional). In other words, starting with a full tank (and functional vent or cap ajar), flow from the petcock remains steady and unchanging until the tank empties.

The peanut gallery has spoken. :lol:

Good Luck!

Patton wrote:

LP440 wrote:

Patton wrote:

low on gas and hit some moisture in the tank? Nope. Because fuel level would not prevent any moisture from settling to bottom, as gasoline floats on water.

OK...I agree with all....but I am a little confused by this one......am I understanding that the only way you can have a moisture problem is if you run out of gas?....

Regardless of fuel level inside tank, any water will sink to the bottom and pass on through the petcock.

The manual (non-vacuum) petcocks have a sediment bowl where any water is supposed to collect without going on through the fuel line toward the carbs. With sediment bowl fitted, routine maintenance includes unscrewing it and dumping it and cleaning the round fuel filter screen which sits atop the sediment bowl.

Imo, the tank fuel level alone (high or low) is immaterial to volume or "pressure" of fuel flow from the tank (provided the cap vent is functional). In other words, starting with a full tank (and functional vent or cap ajar), flow from the petcock remains steady and unchanging until the tank empties.

The peanut gallery has spoken. :lol:

Good Luck!

OK...sorry...I misread what you originally said....I took it as the water would stay up....I just read it too fast....but now I totally agree.....I just think I had some moisture that made it to the carb for just a short time......the bike seems to be ok now....with the exception that it is 27 years old of course...lol....still runs good and is very reliable though......

Thanks to all you guys.....this forum is just as helpful as a few years ago when I was posting here. I plan to check in regularly again to hopefully help out if I can and pick your brains.