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Getting detonation at part throttle

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STOCK 07 kx450f.. bike runs great, no bogs, runs hard, starts ez..I have a fuel screw installed.

however: On any instances that I am light throttle, I am hearing some detonation going on.. I am running 93 octane in the bike of course.

IF I give it more than half throttle the bike doesnt knock...

I tried messing with the fuel screw, it reallly doesnt seem to do much, atleast for the knock.

So what do I do now? I am not much of a carb tuner, previously only worked with FI setups before, and changing some values in some cells is a little different than jetting..

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first thing that comes to mind is how do you know its detonation you are hearing and not some other noise? Lots of clicks, whirs, slaps, knocking noises going on with a dirt bike.

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u know what I have thought the same thing myself.. and I have let it go on for a while now thinking that it could be something else...

I dont know that its detonation, and I havent looked at the piston either, as its still on the original top-end.

It sounds like its coming from the engine, and its a tapping sound, really rapid tapping sound to be exact. It only happens when I am at part throttle.. If im on a road, and im just cruising along it will do it, but if I twist harder, it goes away..

I got a fuel screw to see if that would get rid of it but it doesnt seem to do much.. I guess one way I could figure it out would be to run some race gas and see if it goes away.. if it does, then viola gauranteed to be detonation.

What else would make a really rapid knocking sound like that.. no other bike i have owned or ridden has made that sound? I am not attempting an argument, just looking for an explanation that I cant find myself

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Really? even after the bike has warmed up and ran for hours?

I thought about piston slap but it doesnt seem to make the slapping at idle.. Would the pistons not slap at idle? Especially upon start up when its cold? just thinking outloud here.

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It doesnt happen only when im lugging, (i dont lug it) It happens at mid or even upper rpms just when im light on the throttle...

(ie. if I am just maintaining a speed, such as cruising on a road in 5th gear for a mile or so, I dont like to run it off the rev-limiter for that long, but I am still in the upper RPMS)

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ok unplugged the tps .. atleast i think i did it was the plug right beside the carb.

Only thing that seemed to do was make the bike slower through the midrange

It still makes the sound.. I have a little more details, say I'm just pulling out in first gear easy, it wont make the sound, but if I dont rev it the whole way out, and i just short shift into 2nd gear (more load on 2nd gear at low to mid range rpms) it will do it.. Its one louder knock and then alot of chattering..

If I close the throttle, then really open throttle the chattering sound goes away..

same thing if I short shifted second going into third gear without revving out 2nd completely.

The only tim this really effects me is when I am making turns because you cant keep the bike at full throttle.

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ok cool with me then.. just out of curiousity, why are you so quick to rule out detonation? Is it just not common? or does occur differently than I am describing?

Again not second guessing you just trying to learn something.

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