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2004 Ktm 300 Exc Powerband Issue

Joined
Apr 2, 2015
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#1
Hi,

I was wondering if anyone could assist with a problem I'm having, I have a 2004 KTM 300 EXC. I am a student and bought the bike second hand. The bike is not in mint condition and has done a lot of riding in its life. So with that in mind I’d just like to ask what list of things you would start checking in order to start trying to find the problem. I am mechanically very competent but don't have the money to just replace everything because its used, hence why I'm trying to pinpoint it.
For the first year of riding the bike really struggled to get into band. For example in 3rd gear I would have to accelerate until the bike sounded like it was limiting, then if I fiddled with the throttle for a while, opening and closing it in little bits, it would eventually get into band and pull hard.
I then put a new piston in, pro-x oversize C because my cylinder was abit worn. The problem was better but was still there. I then found a huge amount of carbon build-up in the exhaust which I burned out. The bike then ran much better!
However, when on a flat surface it struggles only a little bit to get into band when in higher gears, but when on a hill climb it won’t pull into band in third and above. Another interesting fact is that if it gets into band in 2nd gear and I carry on accelerating hard through the gears it’ll stay in band through all of them, but for example if I am in band in 4th and change to 5th and then coast for abit, and then change back to 4th and go for it, it will sound like its limiting and won’t pull unless I keep playing around with the throttle and it may or may not get back into band.
  • Bike doesn’t smoke and no splooge coming out the exhaust.
  • Doesn’t lose gearbox oil.
  • Clean power valve system and I'm fairly certain the problem is not caused by its setting because I've played around with it to see if it made any difference.(I know you shouldn't move it but I assumed the previous owners had adjusted it)
  • I run 50:1.
  • Jetted according to the ktm jetting chart.
  • Noticed that the float level was set leaner that factory spec. I can send photos.
I was thinking maybe:
  1. Compression
  2. Reeds
  3. Crank seals
  4. Floats and jetting (due to worn carb)
 
Joined
Apr 2, 2015
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#3
Hi, thanks for the reply. I'm from South Africa(thought it would be displayed next to my name).
The pipe is a pro circuit platinum. When it get into band it goes like the clappers, it's not tame. I figured if it were the pipe it would be tame right to the top. How would I go about changing the ignition timing?
 

jaguar

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Jul 29, 2000
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#4
I think your assumption about the pipe is erroneous.
I design pipes and know that to make a pipe hit harder then you usually have to narrow its powerband. Maybe PC made a mistake with their design or maybe it was on purpose. When I get a request to design a pipe I first find out what the rpm spread is between gears that the pipes powerband has to cover.
To change the timing just rotate the plate holding the stator coil after loosening its screws.
 
- a d v e r t i s e m e n t -

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Apr 2, 2015
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#5
Oh I see... Designing pipes sounds really interesting. I'm studying mechanical engineering hence the curiosity. Ok I'll have a look into both those areas. Timing and pipe! Thank you for your help!!
 
- a d v e r t i s e m e n t -