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250SX-f low power

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Hi, my 250 sx-f 2011 does not feel as strong as it used to. looking at the cams their half a tooth unalligned. there is no way i can get them 100% alligned atm.
I didn't tight the oil draining plugg and lost all my oil at the beggining of the season. Ended up breaking the small fingers in the head( rockerarms or whatever), and the intake cam sized into the bridge. got all that fixed. but could the camgear have twisted somehow, or the chain stretched?

got new piston btw, and got 5% on a leakdowntest...

IMAG0257.jpg

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They can move on the cam

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If you turn the motor over, those two dots will re-align, you can see one is pointed up and one is pointed down..

You should for sure check to see if thats actually TDC or not.

5% leakdown isn't too bad.

Umm, cam chains do wear out, cam chain tensioners do wear out also and the OEM hydraulic one is known to be a POS, so most people replace it with a mechanical ratcheting style.

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hmm, that picture is taken with the engine locked, meening it is tdc right? but would i feel a diffrence if they where unaligned with half a tooth? And how important is the stuffing in the muffler? the tire rubbed a hole in it. and guess some of the "stuffing" went out. hole is fixed, but didnt get new "stuffing"

Edited by melfjord

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how old is the cam chain . replace for a new (take oem and no afthermarket) . the cam sprockets can NOT rotate on the shaft , there is a round key in it . when you replace the cam chain look good that the 2 dots on the intermidiate sprocket align with the one dot on the cam sprocket.

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Sorry if this model has keys on the cam , my advice is then wrong , some ktm models are pressed on and can slip , the packing is vital for decent power

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Are you saying it doesn't feel as strong as it did before the rebuild or as strong just after the rebuild?

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Cams look fine to me.  As your chain stretches you're going to get a little misalignment.  I own the same bike and I've learned something weird about it having to do with power loss.  For a number of rides my scoot ran fine but didn't quite have the power it should.  Then one day it started to bog noticeably so I went in to change the inline filter at the injector.  When I went back out the bike had at least 4 more hp.  Meaning that long before that filter actually plugs up enough to notice it, it can affect the amount of fuel getting to the injector.  That filter takes just a couple minutes to change so now I swap it out every 2-3 rides with a clean one. 

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the power loss happend after the rebuild, and it got harder to start up (valve in spec)
the chain has mabye 80 hours on it.
the previous owner updated the fuel filter to the -12 i think. its a big filter outside of the throttle body. Are they known to plug up fast?

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the power loss happend after the rebuild, and it got harder to start up (valve in spec)

the chain has mabye 80 hours on it.

the previous owner updated the fuel filter to the -12 i think. its a big filter outside of the throttle body. Are they known to plug up fast?

 

I am not aware of what KTM has done to fix this problem on the newer bikes, but I don't remember seeing a large inline filter in the parts diagram for the '12 or newer.  A big inline filter may not trap particles as small as the one in the throttle body inlet so if the previous owner left it in, you might have the same issues many owners have had with this bike,  If the previous owner took the filter out you may run the risk of plugging up the injector instead.  From my experience a plugged filter can cause hard starting, poor idling, and loss of power.  This is my first FI bike so I am just learning too (the hard way).  Since I've been keeping on top of this filter thingy, my bike has been running awesome. 

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this is how the filter looks like...

the bike ran mabye 30 min without oil. hard to tell when oil plugg got loose... but i was not on a track, just on a field fooling around.

IMAG0263.jpg

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I changed the fuel filter, and i got the muffler repacked. it still lack's power, do you guys think i should get a new injector? its expensive so i want to be  sure

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Which filter did you replace?  Again, it is the tiny filter that fits into the injector inlet tube that causes the problems.  I only mentioned this because it is such a common problem with this particular model and is so easy to check.  If you are having a fuel system problem you should feel the motor running weakly when you open the throttle quickly or wide open versus a mechanical issue where it will usually run poorly all the time.  If it is a fuel problem my guess is first the tiny filter being plugged and second a bad fuel pump.  If it is mechanical that could be number of things since you broke your finger followers etc.  Did you pull the valves out and check them?  A broken follower can damage the top of the valve, keeper, retainer.

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