Tuning 660

I'm tired of being kinda close on my jetting. I know there are a couple of areas that really need improvement so I got a AFR gauge and I'm finally going to get this done. My question is what ratio should I tune to. I know that 14.7 is stoichiometric but I also know that we need to run richer than this. I'm going to guess at 13.0 to 13.5 but would like some input from someone that has one dialed in.
Thanks:)

12.5 at idle 12.8 to 13.2 wot,leaner than that and u will generate heat from being lean.

Thanks! Can't wait to get this thing humming proper.

Glad to help when I can,let me know how it turns out.

OK So been messing with this for awhile now. I can tune in all aspects of the carb with no problem except for one. Just off idle under load there is 1 really rich spot and whatever I do to get rid of it has no effect. It's bad enough that if you stop on a steep hill you can't get moving again, just sputters and floods itself. Once past this spot it runs perfectly. I'm starting to pull my hair out on this one and I can't afford much of that.
Is it possible that the pilot jet could do this? It seems to me like the slide is pulling up too quickly. I even blocked off one of the vacuum holes in the slide to see if this improved it but to no avail, still rich on bottom and leaner up through the mid. Ideas????

Has anybody messed with the spring inside the slide?when its all together put your finger inside the carb throat and see if the slide goes up smoothly,does the rubber diaphragm have any pin holes in it?just a few things to check.

also check the float level,it could be off and letting too much fuel into the bowl,also is the main needle set to stock specs?if it was raised up it to high it would cause the problem.

Stock spring, needle and #40 pilot jet. I tried a couple of different needles and all work OK after it gets over this rich hump just above idle.
If you are on the flat and just drive away you don't even notice it, trying to get moving uphill is a whole other story.
I haven't measured the float level, thought about it when I was in there but it didn't look way off. Will double check it but seems like I bigger problem than just that.
I can be at 13.5:1 on AFR at idle and when I initially apply throttle it hits 10:1 and as soon as it starts to rev a little 12.5-13 all the way to WOT.

try it without the snorkel and see what it does.

go 1 smaller on the main and it will go away

Tried that - 3 sizes - still crazy rich just above clutch engagement, basically as soon as it starts to come under load. What I have done now is increase the spring rate to hold the slide down longer and it seems better... in my driveway at least. Hopefully will get out for a tuning run today and get this finally sorted out.

Just a thought on your needle by any chance is the tiny little spring missing?  Not the one on top of the slide.  I just went thru something like this and found out the spring that holds the needle down in the slide was missing so It could move up and down about an 1/8" and it seems under more load and light throttle it would sputter but I think the needle would move when it wasn't suppose to.  Hope this makes sense lol...

Yes, that makes sense. The spring is in there and there is plenty of tension on it to hold the needle down. Good idea tho.

OK Spent the afternoon trying everything I could throw at this thing. I can change the ratio of all areas of the carburation by changing the usual parameters...pilot, main, needle, spring - everything works just as expected except for that aweful rich spot just above idle. Starting to get angry! but not giving up.
 Now for the part that I haven't previously included cause I didn't think it mattered... When I bought this Rhino it had dual Yoshimura exhaust on it. I removed them because of obnoxious loudness and put the carb back to somewhere very near stock settings and added snorkels. Always had this goofy rich bottom end thing.
Does the yosh install require modding something I don't know about that could cause this problem? 

So I figured out the size of the inlet pipe to the airbox really messes with the vacuum signal for the slide operation and this is my problem. What I am doing now is installing a restrictor at the airbox inlet to try and address this. I made it 44mm which is just slightly larger than the carb bore. Can someone tell me what the size of the stock inlet tube is? I wish I had the original.

http://www.ebay.com/itm/Yamaha-Rhino-660-Cold-Air-Intake-Air-Box-Airbox-4-6-HP-CFM-Performance-/171076898428?pt=Motors_ATV_Parts_Accessories&hash=item27d4fa4e7c&vxp=mtr   this is what u need,hook it up to your carb and tie your snorkel into other end,will be like an air resivoire.