300 EXC power delivery


I recently got a 1999 KTM300EXC, bike is in great condition, looks great, just finishing breaking in a new top end (wiseco). Always starts at first kick, got plenty of compression in the kick, and runs great.

Power is really strong, with an incredible low end for a 2 stroke, but I don´t feel THE power that some people describe in the 300´s. For example, some people say to be careful, it will make a wheelie in any gear, mine doesn´t really had that powerband hit, its quite a smooth powerband,and will not make a wheelie without quite some effort.

I like it this way, has a very manageable power, but it got me thinking if everything is ok. I see some post about adjusting the power valves, does the 99 model already got this? Maybe its just a matter of adjustments...

Thank you very much for your help!!


Do you know if the PV is working? it could be staying shut or not opening all the way. Did you clean it when you did the top end. Did you mess up the timing marks on reassembly?

The 300 doesnt have a "hit" but you will most definitely know when your on the pipe.

Hey, thanks for the reply!

Yes, I do know when it´s "on the pipe" :smirk: I just read some people talking about accidental wheelies and that does not happen in my 300...

Yes, PV was clean, all bike was taken apart, bot by me but by the previous owner (I´ve got pics of all rebuild)

Try adjusting the brass screw near the waterpump out flush. Thats the preload on the PV for a sooner hit. Also since its a Euro model it might have a restrictive exhaust that need to be replaced or restrictions removed.

Check the power valve spring as well, and check that the linkage is connected, or the valve wont work. if all is good, try removing the valve spring, goodbye 3hundy, hello 5hundy, take care out there :smirk:

also the gearing will tame it down, maybe its geared too high

Hey guys, thanks a lot for your help!

Orangatangtang, didn´t get the "goodbye 3hundy, hello 5hundy" part lol :smirk:

As I said, the bike runs great, and the power seems pretty good, with a nice smooth hit, but from reading some articles on the 300 "beast" I was expecting something a bit more "wild"...

Bike has been completelly rebuilt, here´s an article about in if anyone is interested :smirk: (in Portuguese, sorry!) :prof:


Hi JP , the powervalve spring system on the KTM is aboutpreloading the valve, or spring pressure, the more pressure, the more rpm needed to open the valve, so you have the ability to have the bike on the pipe either sooner or later in a particular rev range. Taking the spring out means very little valve resistence, so the hit is sooner and stronger (not quite CR500 stronger;) but makes a difference.

Remeber, this is an enduro bike, not a MXer, Mike from Fresno could be on the right track with the gearing , try 50 rear and 13 front, before you try anything else.

Higher octane gas will also help, my 2010 300 will powerstand up till 4th gear, even with a full tank, good luck.

These beasts like to be on the lean side. I would start with jetting.

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