Like a light switch: Power Valve '07 exc200

[camchain]

Problem: Zero transition when getting on the pipe. On/off like a light switch, suddenly takes off like a demented wasp.

Thought I'd sorted this when I did the top end. With barrell off I noticed PV was a bit sticky at start point and found to be tight on rotation of L side gear so I figured this was the likely cause. Everything was well cleaned and after a bit of fettling PV moved freely all the way through range.

Bike back together but problem no better.

Tried different PV setting but same problem, just slightly moved. Took off R cover (showing adjustment marks) and with bike running I could see the valve basically snaps to full open with very few revs. Very interested to know what other owners see when viewing PV movement with bike running? I don't think this would be normal but I have nothing to compare.

I should mention it appears to have a worn lower control arm (the part deeper down near governer) as PV adjuster nut has about half a turn free play. This won't be helping matters, but seems to me there should still be a noticeable transition from closed to open. It's almost like a spring is missing or broken down on the governer somewhere? Anyone had the PV system fully apart have any ideas? I understand it's a ball & ramp type arrangement.

[2_SL0]

Cant say what physically is happening, I find mine fairly smooth (07 200EXC) I can have a looksee tomorrow.

[tommorth]

"suddenly takes off like a demented wasp " hehe mine seemed a bit like that at first fell of the back a couple of times a bit of fiddleing with the air screw helped as did a bit of time getting used to it, mine is somewhat older tho and later ones are supposed to be smoother .

will have a look at how mine moves tommorow
I get off pipe good for coasting , just coming on pipe good time to lean forward a bit, on pipe hold on tight

pretty sure the the different pv settings change the z dimension so only alter the port hight think you can change the revs at which it engages by useing different coloured springs

[Ktmboy]

Not normal Camchain.
Not sure if this model has the interchangable "Auxilary spring" on the RH side of the engine casing. If it has you should check to see what spring it has in it.

[flyingcr250]

Not normal Camchain.
Not sure if this model has the interchangable "Auxilary spring" on the RH side of the engine casing. If it has you should check to see what spring it has in it.

thats what i would check, it can make the engine characteristic quite aggressive. im also having an issue with my ktm, i gave my local dealer the part number off the side of my barrel but they say it doesnt show on their computer even though its an oem part with ktm racing cast in the side.:bash:

[kezzafish]

thats what i would check, it can make the engine characteristic quite aggressive. im also having an issue with my ktm, i gave my local dealer the part number off the side of my barrel but they say it doesnt show on their computer even though its an oem part with ktm racing cast in the side.:bash:

look up "Munn racing" on the net. it's a bike shop in texas and they have a full microfiche of all KTM parts online so you can find your parts and part numbers yourself. Have a look at the mint prices in the US too. Well worth getting your parts from there if you do a major on your bike (depending on the exchange rate at the time) only downside is they won't send OEM parts overseas so you have to have a buddy in the USA

[Danger]

Hey sorry Camchain I have not had the time to come here much recently but I know a bit about these. It sounds like someone has been fooling around with the adjuster and you are correct its a ball and ramp system. Its a bit hard to explain but you would be wise to drain the water pump, lay the bike on the side and remove the right engine side cover and check the ball and ramp system. I have seen the ball bearings get trapped under the spring inside after someone has backed the adjuster nut out too far. Its not a hard job to sort out, take you about an hour feeling your way through the job. You also need to check that the lever arms are locating each other in the correct positions. All a bit hard to explain without going into massive detail which I don't have time for but with a little time and effort you can get it sorted out. There should be no free play at the nut you mention.

My bike was similar when I got mine with 12 hours on it. Either the previous owner had messed with it or I know that someone with questionable skills had set it up for the owner (same guy told me that the jets I was ordering to sort it out were all wrong blah blah, how these guys can call themselves mechanics which such bad advice is beyond me). The jetting was way out and part of the problem was the stock triple stage needle with too small a main jet, but the '07's hit softer than my bike (smaller carb, not sure of the needle etc) but still could be worth looking at. Riding my bike with the stock NOZ series needles you had better be over the front end because after it burbled its way through the rich bottom end it would rip into a lean mid-upper range and you would end up on you a$$ if too much traction was available (like test riding up the asphalt road).

Check the power valve to eliminate that problem first, then if it still exists look at the jetting. There are no alternative power valve springs on these bikes.

[camchain]

Thanks, you guys. Appreciate all the ideas and suggestions. Coming off the easy going KLX and onto this stroppy lil' weapon has certainly required a next-level sharpen up, which is what I was after. I originally thought the short fuse must be what the 200s were like, so bought a 9oz flywheel weight and JD jet kit (I need some help with jetting too). I'd also initially thought the issue could be jetting as it had an NOZI needle in it - skinniest one on chart.

I'd hate to ask people to take covers off for a PV-peek on my account but possibly a good idea to take a gander at your own one while it's running anyway. Certainly interesting to watch it working. PV's jammmed/sticky in one position or another seemed a fairly common prob on KTMtalk. Was hoping to identify a possible likely part so I could order it in advance and avoid some down time.

Danger, I think you may have put your finger on it. The power valve WAS weirdly set all the way past (above) the top mark when I got it. Looks like I may have a few extra loose marbles to contend with. With any luck it might just need a bit of fondling. Welcome back Danger, was getting worried you'd had an accident or something!

[flyingcr250]

look up "Munn racing" on the net. it's a bike shop in texas and they have a full microfiche of all KTM parts online so you can find your parts and part numbers yourself. Have a look at the mint prices in the US too. Well worth getting your parts from there if you do a major on your bike (depending on the exchange rate at the time) only downside is they won't send OEM parts overseas so you have to have a buddy in the USA

that didnt work either, ive been to about 6 sites and they all say no. makes me wounder if its a superceeded (spelling?) part number. will have to investigate further. :wacko:

sorry for hijacking your thread.