Jump to content
Sign in to follow this  

2 Stroke Jetting in Changing Weather

Recommended Posts

I'm thinking of going 2t, and have asked this question in the main forumsicon1.png before but never got a clear answer, so I thought I'd ask guys closer to my area with similar weather in the regional forum but got nothing so I thought I'd try here.

If you live in an area like here in western VA, where I ride from morning til dark most times and it can start out at 65 in the morning and be in the 90s by afternoon of the same day, what do you do? And not only that but one day you can start out with relatively low humidity and get a quickicon1.png shower and have high humidity.
So how often do you 2t guys with similar weather conditions handle it, and how often find yourself breakingicon1.png the Carb open and changing jets during the year?

Edited by tw191

Share this post


Link to post
Share on other sites

Here's the thing.

 

If you have perfect jetting a sea level and 30% humidity (the target that most manf use when choosing jetting) your are starting with a 'given' jetting.

 

If you happen to be at 5,000 ft in the CA desert (0% humidity) you have two changes:

   -  higher elevation means less air = richer condition

   -  lower humidity means more air per cc = leaner condition

 

So, do you re-jet? Do the two changes cancel out? 

 

Yes they do, assuming all other things are equal (which they never are)

  • Like 1

Share this post


Link to post
Share on other sites

So how would that work when both temp and humidity change throughout the day?

Share this post


Link to post
Share on other sites

So how would that work when both temp and humidity change throughout the day?

I only change my needle (0.5clip) and main jet (1 size) for summer vs. fall.   For within day changes I adjust my air screw by 1/4 turn for every 10 degrees change.   I don't formally adjust for humidity as within day humidity changes are relatively minor vs. temp changes here in the pacific northwest.   Wick the throttle method of fine tuning can sort out the remainder as needed. JMHO

 

2012 ktm 200xcw

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×