Jump to content

17 ktm 250sx bog?

Recommended Posts

just went for the first ride on my new ktm after switching from a yz250. so far the bike seems to be hesitating to hit the power band. 

it's hitting it at unpredictable times. not sure why thinking it may be running rich. it was about 45 out maybe too cold for the jetting. if you have any suggestions please let me know. 

Share this post


Link to post
Share on other sites

Colder air will lean out the A/F mix.  

One of the most important things for IDing jetting/carb trouble is to take note of where in the throttle range it is happening, this will give you an idea on which circuit to look at first.

So where in the throttle range is the issue?  Does it idle well? does it have good off idle performance?   You mention powerband so you are probably at least having issues in the 1/2 throttle range and just before i would guess.  Does it run good at WOT?  

Answer those questions and can probably get you set on then right track.  

Share this post


Link to post
Share on other sites

Could be jetting and or powervalve setting

Share this post


Link to post
Share on other sites
1 hour ago, subxero said:

Colder air will lean out the A/F mix.  

One of the most important things for IDing jetting/carb trouble is to take note of where in the throttle range it is happening, this will give you an idea on which circuit to look at first.

So where in the throttle range is the issue?  Does it idle well? does it have good off idle performance?   You mention powerband so you are probably at least having issues in the 1/2 throttle range and just before i would guess.  Does it run good at WOT?  

Answer those questions and can probably get you set on then right track.  

so it feels hesitant untill the lower/middle of the rev range unless i hammer the throttle or slip the clutch while my yz was never like that. it idles low right now and needs some revving before its ready to make power again. runs fine at wot 

Share this post


Link to post
Share on other sites

Sounds rich

Share this post


Link to post
Share on other sites

yeah, probably running rich.  Personally 1st i would try raising the clip on the needle 1 spot, effectively lowering the needle leaning out the 1/8th throttle - half throttle range.  Then take it for a ride and see how it feels at the various throttle points and the transition points and go from there.  If it's better but not great, go one more clip and repeat.  If you run out needle positions before it runs good you will need to change some other things to come up with a winning combo.  Be it the needle, the pilot, the main, try, try, try is all you can do.  Once you get inside the carb post all the settings, needle, jets, ect... and your elevation and temps, maybe someone else rides similar and can give you a decent baseline setup for your conditions and bike.

good luck

Edited by subxero
  • Like 1

Share this post


Link to post
Share on other sites
21 hours ago, subxero said:

yeah, probably running rich.  Personally 1st i would try raising the clip on the needle 1 spot, effectively lowering the needle leaning out the 1/8th throttle - half throttle range.  Then take it for a ride and see how it feels at the various throttle points and the transition points and go from there.  If it's better but not great, go one more clip and repeat.  If you run out needle positions before it runs good you will need to change some other things to come up with a winning combo.  Be it the needle, the pilot, the main, try, try, try is all you can do.  Once you get inside the carb post all the settings, needle, jets, ect... and your elevation and temps, maybe someone else rides similar and can give you a decent baseline setup for your conditions and bike.

good luck

thank you sir 

 

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:


×