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Discussion Starter #1
Ok guys, Im baffled. I had a 505 last yr and sold it. HAd it apart numerous times, Now my coworker has a 08 525. It shut down one day, to never refire. HE tore it down, to find a broken decompression shaft, along with the top of the stock piston looking like someone shot it with a shotgun. Metal all embedded in the dome. The underneath of the head looked bad too. HE bought a new KTM head, all new valves, new 12.5 piston, rings and hotcam. I helped him reinstall everything. We were very particular putting it back together. Checked ring gap, checked valve lash, replaced all worn parts. Issue is, it wont fire. It turns over, but wont start. Here is what we tried
WE have fuel
we have spark
we used ktm locking bolt on tear down
Lined the dots on cam sprocket on reinstall to deck of head

Here is where Im confused. Is it possible to be at the wrong TDC? IF so how would I find that out? I noticed the locking bolt at both TDC will lock the motor the one direction, but you can still turn it the other. Other than the dots on the cam sprocket, is there other timing marks by the flywheel. We paid attention which way the cam lobes were facing on tear down, and put them that way now. Intake lobe is pointing towards carb at TDC. The motor spins freely. Another thing we messed with is the TPS. We readjusted to .65 range i think. (that was a while ago), what setting do you recommend that to be at? Im sorry for the long post, just trying to cover all the bases. Any help would be greatly appreciated, we are at wits end!!!
 

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It sounds like you weren't at top dead center when you timed it. At TDC, the locking bolt will go into a groove machined into the crankshaft (see below) and lock it going both directions. Usually, I'll turn it back out a half turn and make certain that it will stop both ways before I tighten it down again and lock it. If it was locked in one direction and not the other you had the crank turned too far and it was actually "locking" in a backwards direction against the weighted end of the crankshaft.

Another thing you can do to find TDC is to remove the ignition cover and turn the engine until the back edge of raise bump on the flywheel is directly under the hall sensor. (i.e. the pickup) I haven't done that in a while, but I'm almost certain that's how it lines up. It will at least get you in the ballpark for installing the crank-lock bolt and locking the crank down correctly. Remember that if it is in correctly, you should be able to back it off a half turn or so and rotate the crank both forwards and backwards and it should go "clunk!" and lock both ways.

 

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that is the correct way to check it using the flywheel and the pickup^. you can also look into the hole you put the locking bolt in to make sure you are lined up correctly to put the bolt in.

i would guess the above statement is correct in that your timing is off most likely caused by bolt in wrong spot on crank. quite easy to mess up.
 

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Discussion Starter #5
Thank you guys for your help. That picture helped a lot to show me what Im looking for! Im going to help him tomorrow night, and Ill let you guys know what happens!
 

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Discussion Starter #6
Well guys I finally made it back to help my buddy with his ktm. I did what you guys said, we took stator cover off, put the back side of the hump on flywheel under pickup. ran locking bolt in till it bottomed. motor wouldnt move either direction. back in out half turn and motor turned both direction.. no clunk noise or anything. Does this mean im not in that groove. we messed with it many times, with the same outcome. Regardless we proceeded and lined the marks on sprocket to head. checked valve clearance, checked spark, no fire or backfire, nothing. We tried starting fluid once and it acted like it backfired thru carb and flame shot into airbox. My thoughts are the locking bolt is pinching down on side of crank, and not into that groove...but im not sure anymore. One other thing I thought was odd. On my honda, and suzuki the marks on the cam sprocket always lined up evenly above the head line. His is always offset some. Anotherwords one side is 1/4 higher then the deck, the other is 1/4 low. We tried moving one link and its just the same issue on opposite side. Does this tell you we arent in the groove? We are losing patience quickly. Any help would be great!!
 

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yea, your off on timing. your bolt isnt in the right spot still.

here is what i do...

make sure you are on compression stroke.

1- take out the plug bolt where locking bolt goes with the quad standing up on grab bar.
2- set motor close to tdc with the method you did earlier using the flywheel hump.
3- look down the hole with a flashlight. you will be able to rotate the motor slowly with a wrench and look down it at the same time.
4- you are looking for the notch in the above picture^.
5- when you can see it and tell the bolts u shaped will bottom correctly on the notch then screw it in.
6- back screw out just a tad, maybe 1/4 turn. rotate flywheel each way. it should have just a tiny amount of play.
7- you are now in tdc.
 

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Discussion Starter #8
thanks bud, sounds like a good plan.. one dumb question. whats an easy way to tell when im on compression stroke??
 

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Lobes face down. You shoulda put the lock bolt in while cylinder was off. You can see the bolt slide in the grove. The timing gear on flywheel is just above the pick up to be at tdc. . I have no grove in my crank. I have tons of practice at it. Billet cranks don't come with the tdc grove either.
 

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Discussion Starter #11
Well that is why we are in this dilemma. He thought he could do it himself and knew nothing about using a locking bolt. So he tore motor down, broke cam chain and took old piston out, then panicked and called me. My issue is I have no idea since there was no locking bolt till now, if we put the cam in with lobes correctly and on the compression stroke.. So does someone have a pic of lobe direction when its in TDC? If not, I believe the lobe closest to sprocket points to the back of quad..I have him tonight putting the quad on the grab bar like mentioned above, to find the groove, then see how far we are off.
so to clarify, the high spot on flywheel is under pickup at TDC on compression stroke, with cam lobes pointing where??
Thanks!
 

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There are 2 dots on the cam gear they line up straight across the top of head. With the lobe centers down not up! Those dots have to be paralel to the top if head. Piston at tdc
 

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the cap will only go on if the lobes are down also since you would have to apply an extreme amount of pressure to get it on with them pointing up. the first time is the hardest. after that it is easy.

also when your done roll the quad over by hand and dont use the estart. if you go slowly and hear a tick you can still save it. if you do estart and here a clank and then a bunch of pings then youre SOL.
 

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Yes my mistake, lobes down. Checked manual to confirm. I was getting mixed up with the sx engine. Sorry, I probably shouldn't post past midnight when i can hardly keep my eyes open!!!!!
 

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Discussion Starter #15
Ok guys thanks for clarifying. Going back this weekend, to try yet again. One final question. I noticed on the sprocket, that one half has a series of holes cut out of it, and has the stop for the decompression, while the other half is solid. Does it matter which "half" of sprocket is on top at TDC? I assume it would with that decompression stop..
 

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Ok guys thanks for clarifying. Going back this weekend, to try yet again. One final question. I noticed on the sprocket, that one half has a series of holes cut out of it, and has the stop for the decompression, while the other half is solid. Does it matter which "half" of sprocket is on top at TDC? I assume it would with that decompression stop..
The half with lobes will be facing down the button on the cam gear will be at 11oclock
 

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Discussion Starter #19
thanks! Im not sure how you guys know all this, your amazing.. he has the polaris manual, not the ktm one. Its a joke as far as using it to tear stuff down. Very little pictures. Trust me if his book was better, I wouldnt be bugging you guys! I think Im good to go now!! Appreciate it!
 

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Our billet cranks do have locking bolts slots.Try this look on you tube for the KTM RFS valve adjustment video You don't need to find tdc with this method
 
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