whistling noise & running rich (wr426 02)

I removed the air lid cover and disconnected the grey wire this weekend, and noticed a whistling noise when riding. The noise gets louder as I increase throttle. I did not get a chance to put lid back to see if that was it. Anyone else have that noise?

Also, pulled plug this weekend and looked like bike is running rich. I have stock jetting with exhaust uncorked, grey wire disconnected, lid off and yz throttle stop. I thought if anything I might be running a little lean due to the modifications. Any info would be greatly appreciated. The bike starts easy and runs well.

As long as its not sounding like whistle While you work

Sorry it is probably always been there, taking of the top cover will allow for more air to come in.

ou are probably hearing the carb as it creates a vacum on excel

[ August 04, 2002: Message edited by: E.G.O.**** ]

I have done the same mods to my bike and it also

appears to be a little rich but runs and starts fine. you have richened up the mixture due to less

exhaust pressure and your cyl. does not have as much exhaust in it to lean out the incoming mixture of air and fuel.

Don’t worry about it. On my bike, I’ll notice a brief whistling sound if I’m in too tall of gear and whack the throttle. As the bike accelerates the whistling sound stops. At the instant it stops, the engine really picks up and moves! There is zero engine stumbling/bogging though.

Do you know what elevation you’ll be riding? (Helpful to know when re-jetting).

The accelerator pump on my ’02 was like a fountain! If I were you I would definitely do the BK mod before you re-jet.

Do a search for BK mod. You’ll have to drill and tap the outside of the carb. It’s not to hard, just take your time.

Thanks for the info. I am learning alot from this website.

I had an exhaust leak do it many times . If you have ever had your exhaust off you probably need the squash band that goes on the part of the pipe that mounts on the head. About every other time I took the header pipe off I needed one and every time I took the muffler off or re-packed it I had to put some high temp gasket maker in all the seams and connections.

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