Hi
I’ve recently bought a ’99 KTM 125exc after an eight-year absence from dirtbikes. The bike has been raced professionally and last competed in the ISDE in Granada i.e 2000m above sea level. Am I right in believing it would have been jetted leaner to compensate for this high altitude? It’s currently using a 180 main, 42 pilot, has the clip raised one notch on the needle and the air-screw set to 1.5 turns. My manual suggests a 190 main and 48 pilot but from what I’ve read KTMs seem to be jetted rich from the factory.
I live in Scotland with the current average temperature at about 10-12 degrees (if we’re lucky) and I’m riding not much above sea level in tight muddy woods. From idle to quarter throttle the bike is quite erratic and splutters badly with the mid range only slightly better (almost seems like it misfires at times). Half to full throttle tends to be fine most of the time but occasionally bogs (too rich?) going into the powerband. I’ve tried a 45 pilot and putting the needle clip back in the middle position but to no avail.
I realise that all bikes/ conditions are different but any jetting advice would be cool as the bike is very hard work just now in these tight slower areas. I also read somewhere that bunged up exhaust valves can produce symptoms similar to poor low end jetting. Can I check/ clean these without removing the barrel? I apologise in advance for my lack of technical knowledge and any advice would be appreciated – is there any other possible non-jetting problems I should check for?
Cheers
Steve.
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I’ve recently bought a ’99 KTM 125exc after an eight-year absence from dirtbikes. The bike has been raced professionally and last competed in the ISDE in Granada i.e 2000m above sea level. Am I right in believing it would have been jetted leaner to compensate for this high altitude? It’s currently using a 180 main, 42 pilot, has the clip raised one notch on the needle and the air-screw set to 1.5 turns. My manual suggests a 190 main and 48 pilot but from what I’ve read KTMs seem to be jetted rich from the factory.
I live in Scotland with the current average temperature at about 10-12 degrees (if we’re lucky) and I’m riding not much above sea level in tight muddy woods. From idle to quarter throttle the bike is quite erratic and splutters badly with the mid range only slightly better (almost seems like it misfires at times). Half to full throttle tends to be fine most of the time but occasionally bogs (too rich?) going into the powerband. I’ve tried a 45 pilot and putting the needle clip back in the middle position but to no avail.
I realise that all bikes/ conditions are different but any jetting advice would be cool as the bike is very hard work just now in these tight slower areas. I also read somewhere that bunged up exhaust valves can produce symptoms similar to poor low end jetting. Can I check/ clean these without removing the barrel? I apologise in advance for my lack of technical knowledge and any advice would be appreciated – is there any other possible non-jetting problems I should check for?
Cheers
Steve.
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