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Valve Clearance ?

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I checked my valves at 3 hours and the exhaust were a little tight(.004)but the intakes were fine.I just rechecked them (10 hours)and the exhaust didn't change ,but the intakes had NO clearance(!). Is that normal ?How often should i be checking them? Also the plug looked a little rich(i'm useing the JD kit for up to 4000ft).I'm thinking the tight valves might have something to do with that,or should i lean it out a bit(lower the needle/drop the main).I ride mostly the hi dez (2500-5000ft). :)

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Are you 100% sure that you're on the right stroke? I know that if you aren't exactly right on TDC, that sometimes one side of the motor will have plenty of play in the rocker arm, while the other won't move. I would recheck that first.

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Not uncommon for KTM's to not move on the exhaust but tighten up on the Intakes.

Take a peek at KTMtalk.com in the valve adjust section..yes a full section on just valve adjusting.

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For high desert jetting, my '04 525EXC runs perfect with the JD red needle - #3 clip, 170 or 168 main, 45 pilot at 1 1/2 to 2 turns out.

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SOunds to me like your at TDC of the overlap stroke. As Rdo said, go to the KTM talk section on valve adjustment

Don't the intakes open just once per two cycles of the crank ?

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Don't the intakes open just once per two cycles of the crank ?

Yes. It's not uncommon to find the intake gap closed up but 10 hours is kind of quick. I'd keep an eye on them and check them at 10 hours again. They should settle in pretty quickly but they will always need more adjustment than the exhausts. If you find the gap closed up every 10 hours or so, I'd say you got some bad valves, which has happened from time to time.

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The intake valves are very soft, they get beat into the shape of the seat fairly fast then will work well, a few % of leakage for quite some time, couple years is typical.

Having the clearence close up that much could be coincidence, could be a softer bath of valves? could be your reving it more than it likes? These motors pull very good from low RPM.

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Both intake and exhaust do that. At one Top Dead Center (TDC) which is at the end of the compresion stroke both valves have been and will be closed for long enough that it is a safe spot to adjust, (which is the factory manuel way.)

360 degrees later, the next TDC, both valves are open ever so slightly, is called the overlap, if you adjust there you would be backing off the adjusters something like one turn, then when turned to the right spot you would have abt 1mm of clearence which is enough to deactivate the auto decompresor, which can lead to broken starter gears. When adjusted "my way" as posted on KTM talk you adjust the intake when the exhaust is opening, and the exhaust when the intake is closing. This is way easier, puts the adjustment at the center of the heal of the cam lobe instead of a compramise between the sides of the heal on each lobe, no need to remove skid plates, magneto covers or spark plugs and it eliminates the risk of being at the wrong TDC!

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could be your reving it more than it likes?

:) That could be the case,my last three hour ride,they were grading the trails in the desert,i was at one with the beast,and spared no thottle. :)

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I like the concept, not saying you are over revving it but try shifting sooner and see if it does not cover ground as well?

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Hy there,

it is normal that the valves are very tight at the first check. They come with nearly zero clearence out of the box. KTM expects them to "sit in" in the first three hours. So that is normal for the 3 h check.

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Yes, that's pretty normal. My intakes were just about closed up at 3 hours on my 03 450E. Some don't find them that far off but it's a good idea to check them after the first 3 hours like KTM recommends.

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my o5 ktm400 , the intakes were closed at 9 hours and 230 miles but the exhaust were at about 2 thou. adjusted both and at 30 hrs they are still fine

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I was told by KTM dealer who has a 03 450 and 04 450 SX that he checked his valves when the bike was new and doesnt do it unless it gets hard to start cold. I do it probly every 5-6 rides on my 04 450sx and havent needed to adjust mine yet. To get mine to TDC i just remove the spark plug and SLOWLY push the kickstart by hand untill all the rocker arms are at thier loosest. it takes a while to get a "feel" but i havent had any dramas yet

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