colortune with or without yics tool?

Title says all.
Thanks.

 

Manual recommends WITH.

As Fitz just found a while back - also says to disconnect the crankcase breather hose.

 

I did it with the yics tool and crank case connected. WAY TOO RICH. 10mpg. I'm half way done. Seems to run WAY better with no yics tool. I just can't remember how I did it before but it ran so smooth you could barely feel it running with your bare hands on the grips of the handelbars. 50mpg with a windscreen and driving like a gramps at 45-50 mph. Thanks for the fast reply. I'm sure I'll be doing this again.

 

Yep, good throttle response, can't taste the gas when you stand behind it at idle, colortune window turns brite blue when you rev it to 6k or so, and can barely feel it run with bare hands on the grips.......but it still "putts" every now and then. I have the idle at about 1100 and when you listen from 10 feet behind, there is still a "putt" here an there. Probably have to tear the whole engine down, bring all the tolerances to within .0002" of what the book calls for and then it might idle like glass for 12 months or so!

 

Interesting I used the YICS and came up a bit leaner than when I tune without it - I have the best plug color I have ever had but have not put enough miles on to tell about mileage yet.

 

Manual doesn't recommend ANYTHING. The manual says we're not supposed to mess with the mixture screws.

But we are. The factory set them using an EGA (Exhaust Gas Analyzer.) Since most of us don't have an EGA handy, we sustitute a ColorTune and do it visually.

What I found a while back was that in the EGA manual they have you disconnect the breather from the airbox prior to beginning the procedure. Whether or not this would have an effect on visual mixture tuning I honestly don't know. I posted it because it's one more bit of hidden information in regard to the forbidden mixture screws.

The factory manual specifies the use of the YICS blockoff tool during the entire carb tuning process; both vacuum sync and EGA.

Individual results apparently may vary.

 

What I found a while back was that in the EGA manual they have you disconnect the breather from the airbox prior to beginning the procedure. Whether or not this would have an effect on visual mixture tuning I honestly don't know. I posted it because it's one more bit of hidden information in regard to the forbidden mixture screws.
"quoted"
(My turn)
If you dis-connect the breather from the airbox, you would then need to plug the airbox hole, or you would upset the whole " shared CFM volume" idea of having a closed airbox.

Or does that idea not apply to an idle situation ??
As in- - you could idle on pods just as well as a proper airbox ??

 

I'm only reporting what the book says.

In my opinion (which is NOT from the book) I don't think that small of an additional hole in the airbox would make enough difference to upset anything. I suspect that's why Yamaha didn't mention plugging it.

I'm also not convinced that it would make one bit of a difference with the ColorTune. Maybe the EGA could pick up a difference, but I don't think we'd SEE it.

Like I said, I'm not advocating or arguing for or against. I found a technical reference tidbit in a book not a lot of folks have access to and reported it. Yamaha didn't "officially" say anything about tuning the mixture screws except in the EGA manual for the dealers. Every piece of the puzzle helps our knowledge base, some more than others.