How Much CO Is Too Much?

After reading here (or maybe elsewhere) that a rider tamed the on/off jerkiness with a combination of idle and CO adjustments I went back to look at mine. Idle was at the top of the spec range (1600) and CO +1, where I set it back when. I tried up/down in 1 increments and +7 "seemed" to make a difference, I've ridden with it at +7 for a couple days now and believe it made the throttle snatch perceptibly better, but it may be a placebo effect.
Anybody else running with the CO at +7 (or higher)?

I believe the CO adjustment values only represent the percentage of fuel added/subtracted at idle. Zero is most likely Yamaha's "intended" or "ideal" setting. Therefore I wouldn't feel right to add/subtract past 10%.

I remember when I first got my completely factory/virgin WR and the jerkiness was pretty bad, I too then began messing with the CO. Mine was set at -6, I tested -3, 0, +3,+6, and +10. I also tested some really crazy ones as much as +/-30% for fun with no benefit.

I originally settled on a setting of +4 realizing the farther I got from the original -6 the better the on/off condition "seemed" but at the expense of a less snappy and more sluggish feel as the bike had to burn off extra fuel before it could accelerate properly.

Even at just +4 the exhaust smelled kinda rich to me and my brother who is endorsed but doesn't ride still looked like he was gonna get sent over the bars just trying to putt around. Eventually you will need
to adjust the TPS sensor to achieve best performance. After adjusting my TPS and the addition of a fuel controller my CO is now set around -3 and runs about as well as it can. The Jerk is all but gone now but lives on as a manageable surge . FYI my idle speed is only at 1,400 warmed up

TPS adjustement was the biggest gain for me, but the CO-mod helped a little aswell. I think Im about +5

Jens Eskildsen wrote:

TPS adjustement was the biggest gain for me, but the CO-mod helped a little as well. I think I'm about +5

I suppose I'll eventually have to pull the tank and fiddle with the throttle body to get at the TPS screws .

Mines set to +6, for summer use on mine.
It does start better in really cold temps with it set richer but is a touch rich when warmed up, I ran it on 10 when I used the bike for winter trail riding in cold temps but had to go back to 6 when it got above freezing.

I have my idle set between 1900 and 2000 rpm too this helps with the throttle snatch as well, its the half arsed way of adjusting the tps.

Jens Eskildsen wrote:

TPS adjustement was the biggest gain for me, but the CO-mod helped a little aswell. I think Im about +5

For what its worth I ran my CO setting back from +7 to +3. At +7 it ran too rich for the first few minutes with no distinct benefit later when warmed up.