06 ?

[wagsracing]

I just picked up my 06 yfz and its sweet, but I have one question. When its in neutral and you spike the throttle it cuts out, its fine when you ride it or start out reving it smooth but as soon as you let the engine idel and then rev it quick it cuts out even after the engine has warmed up. This does not seem normal. Im coming from an 03 kfx 400 and it never did it with that machine. Comments please.

[yamaguy]

It might be slightly lean on the fuel screw. This seems to be pretty common due to the EPA settings.
The other thing is these engines rev so quickly the air can not accelerate through the carb quick enough and it will bog slightly.
Even the dirt bikes do this. You can jet it out but then you will be to rich when you ride it.
That has been my experience anyway, maybe someone else has found a cure.

[Doober]

is it after you hold it spiked or is it just when you spike it....cause if you hold it, it might be the rev limiter, but if the other way then i would agree with the guy above

[wagsracing]

It happens only when I spike it. If this is something that is not a problem than I can live with it because it runs great.

[Davids440ex]

probley the jetting, from factory its always lean so bump it up a few

[GNCCracr]

the cure to your problems is the boyesen quick shot accelerator pump cover. As the person said above, this problem can almost be jetted out. But it requires that you go way to rich on both the pilot and the main. I just got my new 06, and the problem was worse on the 06 than it was on the 05. I run a full hmf ballance system with no lid, and I am jetted right now with a 48 pilot and a 170 main with the boysene quick shot. And have NO hesitation or bog. I think I will be dropping to a 45 pilot, becuse i feel that i am still alittle fat on the bottom, and will be testing that in the next few days.

[jr1975atv]

Save your money don't buy the quick shot just order a #35 and #40 leak jet from the dealer i've got the quick shot on my wr cranked 04 and i still needed the 40 leak jet and a freinds 05 has the 40 in it without the quickshot.