Starting problem in cold weather at altitude


5 replies to this topic
  • NorCal

Posted October 17, 2008 - 11:40 AM

#1

I raced up in Nevada last weekend, and my god damn bike wouldn't start in the morning,
yet it started the day before 2nd kick. It was really cold (27 degrees) and the
elevation was 4400 ft. I have taken it to elevations that high before and never
had a problem.

Anyways, we kicked the shit out of it desperately trying to start it before my
minute took off. Finally we bump started it behind the truck. Once it fired there
was some smoke out the pipe, but it quickly went away. The bike ran great the
rest of the day/race. No complaints what-so-ever.

I just fired it up today in the garage. No problems. Runs like champ. Now I'm
super nervous this motor is going to fail on me.

The only thing I could think of is a valve tightened up; however, if that was the
case, wouldn't starting it in my garage just a minute ago be a pain in the butt
as well? Something doesn't add up.

  • llamaface

Posted October 17, 2008 - 11:45 AM

#2

I raced up in Nevada last weekend, and my god damn bike wouldn't start in the morning,
yet it started the day before 2nd kick. It was really cold (27 degrees) and the
elevation was 4400 ft. I have taken it to elevations that high before and never
had a problem.

Anyways, we kicked the shit out of it desperately trying to start it before my
minute took off. Finally we bump started it behind the truck. Once it fired there
was some smoke out the pipe, but it quickly went away. The bike ran great the
rest of the day/race. No complaints what-so-ever.

I just fired it up today in the garage. No problems. Runs like champ. Now I'm
super nervous this motor is going to fail on me.

The only thing I could think of is a valve tightened up; however, if that was the
case, wouldn't starting it in my garage just a minute ago be a pain in the butt
as well? Something doesn't add up.


As usual, my experience is not specifically with a yamaha, but my big 4stroke is extremely difficult to start when it's cold if i use normal 15-40 or 15-50 oil in it. For winter time i run 10-40 or 5-40 or even the mobil1 0-40 (european car formula) so that I can kick the damn thing over.

As we were driving into the staging area from carson, the thermometer read 20 degrees. I saw folks building fires next to their bikes to warm up the motors, lol.

when i still lived in ely (a cold cold place), i tried desperately for hours to start my bike in the garage (warm weather, mid-20's or so) before i finally got a bright idea, drained the oil, got some 10-40 oil, warmed it up in the microwave, dumped it in, and 3-4 kicks later (to distribute the warm slippery oil) the motor fired right up.

what kinda oil were you using?

  • Wiz636

Posted October 17, 2008 - 11:48 AM

#3

yet it started the day before 2nd kick. It was really cold (27 degrees) and the
elevation was 4400 ft. I have taken it to elevations that high before and never had a problem.


I'm betting that it was simply the cold temps outweighed the gain in elevation and you were running pretty lean on the pilot. Couple that with the gas hitting the very cold metal and de-atomizing.

I have not had my '08 in cold weather yet but my '06 was a bear to get fired up when it got really cold. Any other time it fire up 1st or 2nd kick.

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  • llamaface

Posted October 17, 2008 - 12:03 PM

#4

fwiw, after sitting out all night, both our 2 strokes were a pain to start as well, but at least the cold doesn't thicken up the oil quite as bad on a 2-stroke.

  • NorCal

Posted October 17, 2008 - 12:09 PM

#5

what kinda oil were you using?


I can't remember what I used, but I'm pretty sure it was the thick stuff. The oil
was brand spankin new, too. So I'll bet that may have been the problem.

  • grayracer513

Posted October 17, 2008 - 07:48 PM

#6

I'm betting that it was simply the cold temps outweighed the gain in elevation and you were running pretty lean on the pilot.

It's almost certain that that's what it was. When you consider the ambient temperatures in your jet selection, you are assuming an engine at full normal operating temperature. You, on the other hand, were working with an engine that was dead cold. With all the internal metal surfaces at below freezing temps, the fuel simply does not vaporize well, if at all, and you need a huge amount of it, along with strong spark and a good plug to get it to light off.

As far as the oil goes, 20W-(whatever) is only recommended down to 50 degrees. After that, 15W-* is good down to 32, and 10W-* are good down to 0 degrees F.





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