Popping/Clicking under acceleration?

Hey guys,

01 yz426f

On occasion it seems that my bike pops and crackles under acceleration...I cleaned the spark plug (but didnt replace it) and cleaned the air filter....I use 91 Octane fuel...but the problem is still there. No noticeable loss in power, it just doesnt sound right...

Just wondering what it could be and what I should check first. Thanks for the help!


OK, before the old-timers get on here and slam you with the "USE THE SEARCH FEATURE" rant, I'll let you know that this subject has been hammered up and down millions of time on this forum.....with that said, I would start making small adjustments to the fuel screw. If your performance is how you like it then usually the jets don't need changed. If you don't have an adjustable fuel screw, you can use a short stubby screwdriver. I would recommend get a new adjustable fuel screw, that way you can make adjustments easily in the field when conditions change. Hope this helps.

I don't remember many discussions regarding popping under acceleration.

Is the problem part or full throttle accel?

i really only noticed it under full or near full throttle acceleration.

I will do a search to see what I come up with...sorry.

Is the bike actually popping, or is it jerking hard under a load? And, if the latter, is it only in one gear, or more than one?

its not jerking, just popping/cracking...It does it in all gears and all rpm ranges as long as I go wide open or close to wide open throttle.

I think its my air/fuel mixture and the next time Im out at the track I will play with that and see if it improves.

Your idle fuel screw has nothing to do with the performance at or near full throttle. Try going up a size on your main jet.

up a size on the main jet...okay...but it doesnt make a lot of sense to me.

It was running fine one day and then the next time I took it out it started the popping/cracking...although it is getting colder here so maybe the air temp/humidity has affected the tuning.

thanks for the help guys

Well, if you aren't sure, you could try actually replacing the plug. They will sometimes develop a conductive glaze that can't simply be washed off.

I'm thinking you possibly got a bad batch of gas and you're getting some detonation. Try flushing the carb and tank with new gas and then see if it still does it.

Will do, I'm going riding tonight so I'll give it a shot.

i have been having the same problem... than tonight i found a hole in my fuel line... do you think when i open her up she sucks air and leans out?? im replacing the line asap, but jw if that would cause this.

... do you think when i open her up she sucks air and leans out??
No. There is never any vacuum in the fuel line.

alright well then i guess its ignition still, god dang this sucks, i might just go back to the yz stator and not ride her on the street... nothing is grounding out or anything, its all fine...

Okay I went to the track after cleaning my air filter, replacing the spark plug and draining the fuel and replacing it with fuel from a different gas station...and problem solved! Thanks for the help guys!

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