temperature and humidity

Discussion in '2-Stroke Engines' started by Mike Hunt, Dec 5, 2009.

  1. Mike Hunt

    Mike Hunt Member

    lately ive noticed that the bike takes a really long time to warm up, if i give it gas too soon it just dies. also at high rpm's it 4strokes badly, i had the same thing happen before when it was warmer, but after it warmed for a few minutes it would work properly. also i noticed this happens when its raining or really humid, but not in cool dry weather. im not sure if this caused it, but this started happening when i reduced the spark gap... any ideas?

  2. Mike Hunt

    Mike Hunt Member

    hmm looks like it was the plug, i gapped to it to what it was before ,1/16 of an inch, apparently its supposed to be a lot less, but im getting way better performance like this, so im gonna keep it the way it is.
  3. Al.Fisherman

    Al.Fisherman Active Member

    When it is both rainy and cool the atmosphere is saturated (meaning holding max moisture). This is not good for a engine that is tuned up on a clear warm day. This effect is noticed much more in normal aspirated engines (carburetor), then fuel injected engines. End result will be more ambient air then needed and a cooler running engine. One way to see this is to tune up a engine at sea level where the air is thick, then go to like Denver (above 5,000 feet) and a loss of performance occurs due to lack of air/oxygen. The fuel/oxygen ratio is knocked out of kilter.
  4. Mike Hunt

    Mike Hunt Member

    humidity is definitely having an effect, a couple days it was around 2C and the bike refused to start, i thought it was because of the cold, but the next day day it was around -5C and it fired right up before i got to the end of my drive way.

    the question is, how do i tune it so it runs in cool humid type weather