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Discussion Starter · #1 ·
Hi, so I was on my weekly dune ride on my 2009 KTM 525 XC, and after about an hour or so of hard riding and cruising, my engine suddenly started to make an abnormally loud metal racket. So I quickly stopped and turned the bike off, I then started it again so I could trace the noise and hopefully troubleshoot it. The noise was coming from the top end, and the metal tapping sound increased simultaneously as I revved the engine. Pulling in the clutch made no difference, so I am sure that it is from the top end. I decided that it was loose valves, so I decided to ride back to camp in high gears at very low revs; I got about 500meters and I stalled it, then it wouldn't start and the battery eventually died. I then got towed.

What could be the problem?
Could one of the valves suddenly get loose?
Have any of you had a similar experience?

-If this helps, around 12 engine hours before, I installed a high compression JE piston 13:5.1 and a stage 1 HotCams cam shaft (I am running 97 octane with NOS octane booster so, it should be 102 octane)
-I also havent checked my valves since installing the the piston and the camshaft

I am going to check my valves today.

Could you guys please help me urgently because a few pro Redbull MX riders are coming to my country and we (including myself - god willing) are going to ride with them.

Thanks in advance
 

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get it washed and get the valve covers off firstly. Could be something to do with rocker arms, possible a broken arm or the locking nut came loose and come way out of adjustment or even fallen out!!


The whole head may need to come off to check for piston damage etc.


Hope its not too costly for you....
 

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102 sounds low for 13.5... maybe xc can handle less octane than sx though. check your compression. anything under 95, i think it is, is shot. when my sx piston cracked it was at 65 psi...
 

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yup 13.5 is a race gas top end............ personally I wont trust octane booster additives.
 

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You really need to switch to a real race gas. Octane boost is not something to trust or rely on. As for the noise I would guess your problem is in the top end most likely related to the top end rebuild. I would first pull the cam chain tensioner and check to see how many clicks you have remaining and be sure that it is still springing in and holding as its supposed to. Next I would pull the valve cover and make sure all adjustment nuts are still on and tight. Also pay close attention to the tips of the rockers. Make sure they move freely and do not have any play in them. Your problem should be apparent by this point. when you find the problem or if you make it this far and havent found any issues yet report back and let us know.
 

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Discussion Starter · #6 ·
Turns out, that my dad didnt add any octane booster to the petrol, so I was running 97 octane with the little fuel i had left in my tank, so it is definitely related to the petrol, what could be the possible problems.

And thanks for the tips on the octane booster; race fuel should be available in my country by next month.
 

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Discussion Starter · #8 ·
On further note, my cam chain tensioner still had 3-4 clicks.

I drained the oil, and it had the normal small amount of metal shaving stuck to the magnetic bolt, but a very low amount of cleanly shaved polished metal in the oil screen which I dont normally see, and by when i mean a very low i literally mean 0.01 grams.

All my adjustment nuts were still on tight; i havent check my valve clearance yet, because I figured it isnt the valves, and I am personally too lazy to remove the generator cover then find TDC and lock it with a screw driver.

I decided to drain all the oil from my fuel tank and from my carb, then add octane booster and hopefully fire it up.

Will keep you posted
 

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TrainWreck1.gif Are the bolts that hold the cam gear to the camshaft tight?
 

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Try this: [video=youtube;hWS9RuEQzc8]http://www.youtube.com/watch?v=hWS9RuEQzc8[/video] Yes it is a bike but the 1/6 turn and adjustments are all the same.
 

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Discussion Starter · #13 ·
Thanks Thumper racing, but won't the exhaust and intake valve movement differ from in the video since i got an 806 cam?
 

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Discussion Starter · #14 ·
Pulled my head off, and found out that it was a broken rocker arm (the metal bit which holds the bearing). Atleast, I now know what the problem is and what caused the metal shavings. The thing now is, how do I get the piece of the broken rocker arm (2cm X 0.5cm X 0.5cm) out of my engine case, before it causes any further damage?
 

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Thanks Thumper racing, but won't the exhaust and intake valve movement differ from in the video since i got an 806 cam?
Valve adjustments are the same whatever cam you have.

Pulled my head off, and found out that it was a broken rocker arm (the metal bit which holds the bearing). Atleast, I now know what the problem is and what caused the metal shavings. The thing now is, how do I get the piece of the broken rocker arm (2cm X 0.5cm X 0.5cm) out of my engine case, before it causes any further damage?
If the piece is in the head then you just have to remove it, if it is in the bottom of the crank case then drop the oil and hope it comes out with the oil, either strain the oil through something or stir a magnet through it, you may even find it attached to the magnetic drain plug - assuming the rocker arm is made of magnetic material.
 

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Discussion Starter · #16 ·
If the piece is in the head then you just have to remove it, if it is in the bottom of the crank case then drop the oil and hope it comes out with the oil, either strain the oil through something or stir a magnet through it, you may even find it attached to the magnetic drain plug - assuming the rocker arm is made of magnetic material.
It didn't come out in the oil, and it wasnt in the head. Should I remove the generator side cover or the clutch side cover and fish for it with a magnet?
 

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its most likely stuck to the back of the flywheel. pull the cover and have a look. there is a screen over the hole that allows oil to transfer back into the cases from the side cover which should have stopped it from making it any farther
 

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its worth a shot. have to get it out. you can also try taking the covers off and tiping the quad up and to the side to make it roll around to where you can get to it. depending where it is you could get it. good luck i had to do that with mx sx once!
 

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Aaron, 100LL av gas is a good alternative. Plenty of guys running that with good results.

Sticko, your brit gas is better than most mate………. 98's cutting it fine though………

we can get 98 here, I do run it through the LTR at 12.8:1 but just cant convince myself to run it in the SX , i prefer the 110 av gas we get locally, plenty of lead, great brew !
 
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