KTM erratic at high rpm

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Jun 11, 2001
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#1
I have a 99 KTM125exc which has been running well for a while after sorting out some jetting problems but it's now running erratic at higher rpms. I stripped the carb and and checked it for dirt but it was clean. The air filter was also clean as I had only used the bike (briefly) twice since cleaning it. However, my airbox had a pool of oil lying in the bottom. I thought I may have over oiled the filter but I used silkolene air filter oil which is blue and extremely tacky, the oil in the airbox looked like transmission oil!

The bike starts first time and runs good at 1/4 to 1/2 throttle but is spluttery at 1/2 to full. It feels like the main jet is too rich but the jetting was fine a few weeks ago and the temperatures or riding conditions haven't changed. I haven't tried changing the main jet as I was concerned at the amount of oil collecting in the airbox and thought the problem could be mechanical rather than a jetting one.

Does anyone know what the problem could be?
 

marcusgunby

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Jan 9, 2000
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#2
Check your reeds they are known to wear quick.Use 2000 model ones as they last longer ot a v force works well on the KTM.
 
Joined
Dec 18, 2000
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#3
Checked the reeds last night and yes they're frayed at the corners.

marcusgunby - do you know where I can get vforce in the uk?

thanks...
 

marcusgunby

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#4
hardcore racing are the importers but i think wildmoor m/c has one-they should i sold it to them, if you need the number get back to me.