Quick Tuning ?

So I finally got my 06 wr450 broke in then did all the mods (air box, carb stuff, smog removal, pmb insert, grey wire, and a Boysen Quick Shot pump cover) and had it out yesterday for some fine tuning. Needless to say I am stoaked on the bike and with a little time setting the Mixture screw it is smooth throughout the throttle range and feels as snappy as my honda 450 it replaced. Here's the question.

When let off the gas there is a slight popping sound in the motor as it decelerates. Not an exhaust pop from the tailpipe, more like a pinging. It's only when off the gas and coming down from medium to high revs. I'm curiouse if that circuit might still be a little lean and that's what's causing it. This is the first TPS / ACV carb that I have dialed in so I'm also wondering if those systems might be causing it and this is just normal. Like I said the bike runs great otherwise... Jetting is a 168 main, 48 pilot, GYT-R needle 4th clip, stock leak, leak air, etc. riding at or near sea level. (El Centro, CA spots)



Check for a slight leak at the header.

Turn the fuel screw out another 1/4 to 1/2 turn.

Good point, new bike didn't even think to check there, thanks.

Actually it may be the chain slapping the subframe/swingarm. The WR's are prone to that. Try adjusting the chain to the minimum slack and see if the noise goes away or changes.

I was gonna say the same thing...... Check the inside of your sub-frame for scratches where the chain is hitting, you seem to only hear it after you let off the throttle.....

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