Whats richer...

[Black Sled]

...the stock carb needles or Factory Pro needles on 2nd clip from the top?

I am retuning for my new pipes.  Swapping out the stockers for the FP's got rid of a major flat spot around 3200 rpm, but overall still not perfect.  Not sure if I should pull the prefilter or go up to 3rd notch.  The weather has been so variable that I hesitate to judge too quickly. 

Having trouble reaching the FP guys, so I'm hoping someone on the board knows.  The insight would be helpful.


Thanks,
-Ken

[sandy]

To make small adjustments, start with the pilot screws. If that doesn't make it right, then return pilot screw adjustment to stock and go up on the needle setting and start over. I have dyna-Jets on the 2nd notch down and pilots at 2 1/2 out. Very small flat lean spot but 36 MPG in town and 40 highway.

[2qmedic]

I have been thinking about changing out the jets in the carbs also.

May I ask what is the jet size that you have?
Did it change the mpg for you?
What was the performance change that you noticed?

thanks for the insight,  

[Black Sled]

I have been thinking about changing out the jes in the carbs also.

May I ask what is the jet size that you have?
Did it change the mpg for you?
What was the performance change that you noticed?

thanks for the insight,  

I have tried several jet/needle/spring/filter/exhaust/timing combinations.  Just about to the point where I'm tired of playing, but it has been fun & educational.  Here's what I think I know:
1) a main jet size is not warranted unless you modify the air box - the snorkel design on the box limits the maximum air flow into the engine.
2) the 38 slow jets improve exhaust sound (fatter) and negate the need to choke (ever).  They seem to work better with aftermarket needles than the stock needles.
3) Valk engine is extremely flexible.  Way too rich, way too lean, it always starts and goes down the road.
4) through all the changes I've always gotten pretty much the same gas milage.  I believe riding style (speed) and road conditions (wind) are the overwhelming factors.

I have 38/100 jets with FP needles, Dyna 3000, K&N and MarkT's pipes.  Sorting still in progress.  

Hope this helps...

[2qmedic]

It seems as the way to go is with the 38 slow jets for the starting, idle and slow speed response from what I read.
I would like to get the 36plus mpg that others have reported. Me, I average 32mpg. I know that I didn't buy the Valk for the mpg, but a few more would be nice.
Only once have I ever got over 40mpg and that was on a ride with a really slow road captain. I may not be a spring chicken anymore, but I sure ain't old and senile.
Thanks for the info.
Enjoy and ride safe

[Ricky-D]

In this thread and in other threads on the forum I've read postings regarding flat response or flat spots at certain rpm's.

That doesn't make sense since the Valkyrie has CV carburetors and are independent of the throttle you turn. The slides inside the carburetors react to the pressure differential (ambient/manifold) developed by motor rpms and the butterfly that you control with the throttle.

Indexing the throttle is a much more needed and basic preparation for determining what may need to be adjusted with regards to the jets and needles.

It seems to me that it is entirely premature to start to experiment with these carburetor adjustments based on speed or rpm's before understanding how the carburetor is designed to operate and the range and overlap of the different metering systems in the carburetors.

Low miles per gallon usually is the result of, and can be laid at the feet of, lack of knowledge and ill-adjustment of the carburetors.  Non responsiveness is more of the same but can and usually is additionally related to other ignition adjustment errors performed by the "mechanic" of record.

***

[2qmedic]

The carbs are at factory settings,
Electrical system is stock,
Hmmm....
I'm not loosing any sleep

[John U.]

The slow jets and pilot screw setting work together to determine the lean or richness of the slow circuit. I initially set the pilot screws to 1 1/2 turns out when I changed to 38s. That proved too lean but resulted in good gas mileage and a pronounced flat spot at about 2800 to 3000 rpms. I readjusted the pilots to 1 3/4 out and the flat spot pretty much disappeared and the gas mileage was reduced a bit. I still need to use the choke to start a cold engine.
Running country roads at moderate speeds (50 to 65) I usually get about 40 mpg. I run an I/S ICM and the ECT mod. Of course, your mileage will vary with the exuberance of your right wrist.
If you leave the pilot screws as they were with 38s instead of 35s the gas mileage will suffer but you can mostly forget the choke. Other than eliminating the need for the choke, I can't think of a reason to purposely run the engine rich.

[Robert]

The stock and the Factory Pro are almost the same till it reaches about 1/2 to 3/4 way down on the needle. in fact I think the Factory Pro is a little leaner in the upper portion of the needle and a little shorter. Idle adjustment screws will not achieve what you want but radio shack has small washers for electronic stuff and they are perfect for a 1/2 adjustment on the needles. One washer equals 1/2 notch but measure the washers first as they are all not the same thickness. I found that one notch was to much adjustment buy one washer was perfect.

[2qmedic]

Hey Robert and John,

Sounds as if ya'll have been there and done that as are pleased with the tuning that you have done on the carbs. Right now I have other priorities before diving into this, but thanks for the insight as I have no experience with the carbs.
 
Ride safe and enjoy

[Robert]

Hey Robert and John,

Sounds as if ya'll have been there and done that as are pleased with the tuning that you have done on the carbs. Right now I have other priorities before diving into this, but thanks for the insight as I have no experience with the carbs.
 
Ride safe and enjoy

When you do you'll like the results

[Black Sled]

After studying several Valyrie dyno runs from various bikes I came to realize that there is an AFR peak (predominant lean spot) at between 3 and 4,000 RPM on most bikes.  My guess is that the Honda guys did this to improve cruising economy and perhaps emissions.  Since my flat spot wasnt too bad (not a stumble) I did what Robert and others have suggested and shimmed the needles.  Since the front plugs looked really white, I raised those a whole clip (another suggestion).  Seems pretty dialed-in now.  Pulls smoothly throughout the RPM range.  Riding 2 up this weekend 65 to 75 MPH I averaged 32.6 MPG.  So far so good.  Will post an update if there is one.

Thanks to all who have made suggestions. 

[2qmedic]

Yep, thats my average also, 32ish. That is running at 70-75. Guess I can't complain though. It's either run it or get run over!!!

[98valk]

I have oem, factory pro, dyno jet and viking needles in my possesion. Have had cobra needles in my hands they are the same as dyno as are the viking.
the dip is a result of the curve in the airbox intake tubes. longer increase low end torque slightly.
take the curve out, see my other post with pics, dip goes away.
the front two carbs should be slightly richer on the needles than the others. front carbs tend to run lean due to how the bowls get their fuel.  oem needles add washer, others clip and/or washer, run test.

[Robert]

Sled, I dont know if you have a timing wheel or a Dyna ignition but if you dont then bump up the timing and you will see a improvement in the mpg without changing any carb adjustments. You may be able to boost your mpg to 35 to 38 plus a little more power. I did change the mains and did the airbox mod and found that I really like the results. It boosted the mileage and power and just gives a crisper feel to the throttle. I also leaned out the mid and richened the low and top ends to give that cruise range sweet spot that I wanted along with the power and smoother idle. Sounds like you have been playing around awhile maybe a little more?

[Wago]

FWIW - With Super Trapps, stock ignition and 6-degree wheel I was pretty close with .038 slows, .110 mains and adjustable needles in 3rd notch. Was using around 12 to 14 discs in the ST's so pretty big chamber size. Volumetric efficiency must have been quite good because plug color was good even with the big mains.

When I swapped to a set of Vikings - headers and pipes - I was way rich with the same setup. Stock mains - .100 - were a happier setup with the Vikings. It would seem that the Viking setup was not pulling exhaust thru as efficiently as the ST's. All of course varied with different needle settings and various ignition curves with a Dyna 3000 with and without the 6-degree wheel.

[2qmedic]

I looked and did not find the airbox mod that CA ExhaustCoatings was refering to. Does anyone know where it is or know what the modification entails?

Thanks in advance

[98valk]

I looked an did not find the airbox mod that CA ExhaustCoatings was refering to. Does anyone know where it is or know what the modification entals?

Thanks in advance

http://www.valkyrieforum.com/bbs/index.php/topic,8248.0.html

[Ricky-D]

There was chatter one time about baffles inside the air box. Mine has no baffles so I think possibly baffles were only in the early models, mine is a 2000, and/or the export models might have had baffles.

***

[98valk]

There was chatter one time about baffles inside the air box. Mine has no baffles so I think possibly baffles were only in the early models, mine is a 2000, and/or the export models might have had baffles.

***

RD,
if u flip over the top cover, do u have a flat piece that is plastic stud welded to the cover? if u look into the air entrance of the cover do u see baffles/vanes or can u see the filter?