1st and 2nd cylinders leaned out (A/F) by Bear Claw mod and K&N fillters?

[Willtill]

So... I've been running my Rocket now for over a year; with the cut Bear Claw and the three K&N's installed. The coolant overflow has been relocated in the old airbox under the seat; so there's space in front of the first (no. 1 cylinder) K&N filter. As you know, all three K&N's are peeping out into the atmosphere....

So... I've been watching my Predator headers over the last several months. Running a very fat tune from Sam and the bike gets about 30mpg (25mpg when I go ape) so I know she's not lean.

However... the forward Predator pipe on the No. 1 cylinder has a slight brownish tint at the first bend; immediately from the exhaust port. The middle Predator pipe has a slightly less tint and the third Predator pipe has no tint.

So... flip over to the other side of the bike and look at the K&N's. Here is my question:

- is it possible that the velocity of air slipping by the bike is slightly leaning out the first and to a lessor extend; the second cylinder; since the K&N's are out in the open and the 1st (and to a lessor extent) the second are exposed to this onrushing air from speed?

Tunes are developed on a Dyno while the bike is stationary. No slipstream of air from high speed operation of the motorcycle is factored in, especially the bike is equipped with exposed filters on the three throttle bodies.


Thoughts?

 

[oakville]

Leaning out of the first and second cylinders would imply a pseudo ram air effect caused by the filters being in the airstream. If anything you would suspect the rushing air would enrich the first two cylinders as the air is moving at 90 degrees to the intake. Without some sort of catchment (scoop) device to create positive pressure you would create negative pressure across the intake bore. Turbulance or the back of the bearclaw or even your leg could make a positive pressure pocket at the filters but I have no clue how you would test for that.

 

[xhdskip]

Will,
take a look at your plugs,
or just drop the preds and look in the exhaust ports and you'll KNOW the answer.

 

[Willtill]

Will,
take a look at your plugs,
or just drop the preds and look in the exhaust ports and you'll KNOW the answer.

Yes, I need to do one of those two diagnostics.

 

[Willtill]

Leaning out of the first and second cylinders would imply a pseudo ram air effect caused by the filters being in the airstream. If anything you would suspect the rushing air would enrich the first two cylinders as the air is moving at 90 degrees to the intake. Without some sort of catchment (scoop) device to create positive pressure you would create negative pressure across the intake bore. Turbulance or the back of the bearclaw or even your leg could make a positive pressure pocket at the filters but I have no clue how you would test for that.

Interesting. That is the opposite effect from what I was thinking. I need to pull plugs or eyeball the exhaust ports as Skip suggested. If this is so, I will need to pursue a different intake system; but not going back to OEM. Yankee Engineering and G.I. ingenuity will be called upon to fabricate such said device.

Anyone else notice discoloration of their Predator; especially if you have the chrome'ish ceramic coated ones?

 

[budman]

..you think and worry too much..just ride it until you go down and see Wayne Tripp..you'll never be able to 'tweak' it to obtain the results he can with his dyno..

 

[Blastedbones]

I remember Wayne doing some study on exposed triple filters & commenting on these effects.'Course you could always go with a cut bearclaw coverage to reduce turbulence.