Just converted my 2010 KLX250SF to 21" and 18" knobbies, What do you all think are the best mods? I have added a 12T front and 45T rear sprocket and like the improvement, Also removed the snorkel, Bike is very difficult to start below 40 degrees F and at altitude above 5000 ft. Budget non issue, Thanks

 

I'm more a commuter mod guy, but at 5000ft I guess you have already optimised your spark plug options for a good spark at that altitude? Grease up the headstock bearings and flush out the old fork oil. I am tempted by an after market pipe, the U.K. KLX250s come with stainless manifold so a nice end part compatable with tail lights a is what I'm after.

 

I didn't even know they made a sprocket so small as a 12, sounds like that would make the engine over work

 

If you haven't done the jetting, that is almost mandatory for easy starting. I have a link in my signature that has the KLX300 jetting information that riders came up with some years back. Worked in my bike. The other option is DynoJet and KLXter is the go to guy on that stuff.

One thing I did when I did the Marcelino cam timing modification was to disable the auto-compression release, setting it in the disengaged position using wire in place of the spring. Bike starts near instantly and is off choke in less than a minute. I did "test" the starting without the compression release by starting it when it was 8 degrees F. No problem.

 

With that 12T, watch wear on the fore-end swingarm chain slider. That's a pretty small cs for the KLX. You don't want the chain rubbing through the slider and then the swingarm.

Do you know how many links in your chain? I'm adding your experience to this thread: https://www.kawasakiforums.com/forum...-length-42553/

If you can't get the starting improved with a re-jet, consider drilling the enricher jet out to 0.018-inch or so.