Alright everybody. I pick everyone's brain about this issue every 8-12 months. I just haven't found the issue so it's that time again.

My 2004 yfz runs great. Pulls smooth and hard completely through the power band. If I open her up at high rpm's she will sputter and cut out. Usually sputters, cuts in and out rapidly a few times before acting like it's stalling.

It's not the rev limiter. It don't always do it at the same RPM. I grabbed my GPS to see what speed I was running. Around 62 it started. I got up to about 64 before It got to the point I thought I should stop.

Any ideas?

Replaced CDI to no avail.
Lid off. K&N w/ Outerwear. Graydon Proline exhaust. (CT clone?). 168 main.

Thanks

 

sounds like the jetting is off just a tad, also have you ever heard of the zip tie mod for the carb on yfzs?(or have you already done it?) it pretty easy and helps eliminate bog probs on yfzs, and makes em run alot quicker...

The Bog! - YFZCentral

 

Ya, I've heard about it not to long ago. Thanks for the reference. I've got it on my todo list when I get back from lil' sahara in two weeks along with adjusting the valves and the cam mod although I have a feeling that was done by the previous owner.

As far as jetting, it is possible. I slightly adjusted up last time I fought this to no avail but, I see many run a 170. I'm sure I'm getting plenty of air so I'll try that.