Pilot Screws and MPG

[Xtracho]

Any correlation to pilot screw adjustments and MPG? Was just wondering as my MPG sucks after desmogging, new carbs, and Pingle petcock. I keep reading about those that are getting 32 mpg and up on their ladies. Me? I'm getting 25-28 at best. I've got some troubleshooting to do. I like to start with the simple stuff and work my way up (that's short speak for saying I don't wanna pull the carbs if I can avoud it!)

As always, thanks to everyone for your help.

[98valk]

hwy or local cruise speeds, u will notice that only about 1/8 throttle is being used. this is strictly the PJ circuit of the carbs. if using more throttle then that u are using the needle circuit also which means lower mpg. any PJ screw can be adjusted open to 4 to 4 1/2 turns open anymore and larger PJ must be installed.
so if bike is stock opening up the PJ btwn 2-3 turns open will allow running on PJs during cruise thereby better mpg. all circuits mixture screw, PJ, needles, and MJ do overlap in fact the PJ actually affects small throttle movements at WOT which is MJ.
www.factorypro.com has carb tunning in their tech section well worth the read.

[6tigo]

As you open up pilot screws more fuel will flow through them.  Are these new carbs (wow) or re-built?  If re-built, were jet sizes changed?  Also keep in mind that if jets are gummed up they are smaller than they were new.  Clean or replace them, they will flow more fuel. 

[Ricky-D]

In reality, the pilot jet screws affect only 25% of the fuel flow of the low speed circuit.

The remaining 75% of the low speed circuit is controlled by the pilot jet size.

So you can see, gas mileage is not too much of an issue when discussing the adjustment

of the pilot jet screws.

Changing the pilot jets have more affect on fuel mileage. Three times more than the screws.

***

[Patrick]

I think we a little more info on what has been done.
Most pilots are set at 1.75 turns and a half turn more is all thats needed in most cases.

I get 40+ MPG and always have.
100 mains
35 lows
pilots at 2.25
cleaned up intakes
proper sync
2 to 2.5º base advance beyond factory
But, engine cruise speed is mostly at 3K or below. I'm not on the speedways.

[98valk]

see my last post for more info

http://www.valkyrieforum.com/bbs/index.php/topic,67145.0.html

[Xtracho]

I don't do well with acronyms but I will give it a shot:

PJ = Pilot Jet?
MJ = Main Jet?

OK....if that's correct here is a little more info. I purchased the carbs from another member of the board. When I got them I cleaned them and replaced the bowl gaskets. I must admit that my time was limited so the cleaning part may not have been as thorough as it should have been. I do not know if any of the jets have been replaced with different or larger ones. Once installed I had a popping and backfire on the left side between 2500-3500 RPM's. Upon inspection I found a diaphragm spring on #5 that was broken. I replaced that, synced the carbs and the popping/backfire was no more.

The bike runs fine. Idle is set and doesn't creep or fluctuate. Bike is desmogged and new Pingle petcock as well. It's just the crappy MPG now. And if I had done my due diligence with the carbs prior to install maybe I would not have this issue. So, upon arrival back home I intend to pull them again and do a complete check and cleaning. But, I will need some guidance on setting the pilot screws and any other items that I should check, change or adjust.

Mind you, I didn't buy the phat gurl for the gas mileage. If I wanted that I would have just kept on riding my '84 Goldwing.  But these threads about you guys getting up to 40 MPG makes me wonder if I can tweak things to get close to that. Hell, I'd be happy at 35 MPG. Oh what am I saying....I'm happy now...I have a Valk...but better MPG would make me happier.  

Thanks again all...and please feel free to chastise me for not doing what I should have done before I installed the new carbs!  

[valkyriemc]

2K Interstate MPG, Tulsa extended windshield, other - stock

37.4
35.8
34.6
35.5
33.6
36.2
35.5
34.6
32.8
35.3
34.2
32.2
37.3

[Xtracho]

2K Interstate MPG, Tulsa extended windshield, other - stock

37.4
35.8
34.6
35.5
33.6
36.2
35.5
34.6
32.8
35.3
34.2
32.2
37.3

Rub it in will ya! 

[Bone]

My stock 98 Tourer is giving me similar numbers except last fall and this year I have a few 39's and even a few 40's. The bike had 22k on the clock when purchased and 117k now. Haven't traveled this year only rode 6k so far with most speeds 65 or less.

[salty1]

Not to rub it in, but mileage on my bikes is consistently 35 to 40 mpg. The pilots are set at 2.25 turns out and all of the other jetting is stock. I wondering if the needle jets on your bike maybe shimmed.?  For sure if the mains were increased in size, gas mileage is going to suffer. What air cleaner are you using? Has it been changed out?

[Xtracho]

Not to rub it in, but mileage on my bikes is consistently 35 to 40 mpg. The pilots are set at 2.25 turns out and all of the other jetting is stock. I wondering if the needle jets on your bike maybe shimmed.?  For sure if the mains were increased in size, gas mileage is going to suffer. What air cleaner are you using? Has it been changed out?

Using stock air filter and changed out same time I installed the carbs....may 1K on the clock since then. And that's OK...rubbing it in gives me a number to shoot for.

[Otus]

Fuel log from recent trip. I'll admit I'm a lightweight at 155 lbs but I was loaded for tent camping and was carrying at least 50 to 60 lbs of gear and I've done a lot to the bike.

I/S carb springs
I/S icm
4° trigger wheel
Desmoged
New intake o-rings
New oem jets 35/100
Pilots 2.25 out
Bench synced carbs
Rotella t6 5w40
Mobile 1 synthetic gear lube 75w90
Cleaned up intakes a little- just knocked off the real ruff stuff with coarse sand paper.
Ngk iridium plugs
Cut down oem windshield 3 1/2"
Avon Cobras front 40/ rear 42

This is a low mileage 2001 standard with tourer bags and shield. I traveled two lane highways and kept it under 65mph/3000rpm and even on the tankfulls that I ran at highway speeds I was pushing nearly 40mpg.

[Xtracho]

So with all the great MPG reports I now know that I have some work ahead of me. Congrats to all of you getting such good mileage.

[Bone]

The trouble with the Valk is how well they run. I'm always twisting my wrist more than needed. I'm trying to control that urge when going stop sign to stop sign go easy on the throttle

[Patrick]

The trouble with the Valk is how well they run. I'm always twisting my wrist more than needed. I'm trying to control that urge when going stop sign to stop sign go easy on the throttle

Yup, I think the right wrist has more to do with mileage than anything.

[Xtracho]

The trouble with the Valk is how well they run. I'm always twisting my wrist more than needed. I'm trying to control that urge when going stop sign to stop sign go easy on the throttle

Yup, I think the right wrist has more to do with mileage than anything.

That is probably true. But such a large difference in my MPG vs. what others have posted tells me that some more tuning may be required.

[Bone]

I'm not creeping around like I should at my age but felt I was just opening the throttle more than was needed.
It's tecnique I had to learn.

[Ricky-D]

It's strange indeed you would install some carburetors without first ascertaining what exactly they have for jets and needles.

Especially since the sizes are imprinted upon the parts in question.

I'd especially recommend looking at the needles, and if they've been shimmed.

100 main jets are all the bike needs and #35's for slow jets are the recommended size for the Valkyrie.

***

[Xtracho]

It's strange indeed you would install some carburetors without first ascertaining what exactly they have for jets and needles.

Especially since the sizes are imprinted upon the parts in question.

I'd especially recommend looking at the needles, and if they've been shimmed.

100 main jets are all the bike needs and #35's for slow jets are the recommended size for the Valkyrie.

***

As I said, my time was limited as I was flying out to Brazil the following day. But I'm man enough to take the criticism. And I was unaware that the jet sizes were stamped on there. Rest assured it will be taken care of when I return home.

[HayHauler]

The trouble with the Valk is how well they run. I'm always twisting my wrist more than needed. I'm trying to control that urge when going stop sign to stop sign go easy on the throttle

Yup, I think the right wrist has more to do with mileage than anything.

That is probably true. But such a large difference in my MPG vs. what others have posted tells me that some more tuning may be required.

You have figured it out.  I have gotten 38 mpg once, riding 50 mph through the Rocky Mountain National Park.  Never since. 
I have a well developed right wrist and probably use it too much.
But, like Smokin' Joe says "ride it like you stole it!".
I have an '07 Wing for putting around. 

Hay 
Jimmyt

[Otus]

Short shift. Indy car drivers do it to save gas.

[Marinakorp]

MPG

When I first got Belle... I was getting 25 MPG (Or so)... Having TONS of Fun.... living well above 3-4K Rpm (riding it like I stole it)

Then I went on a trip with a buddy riding along the Blur Ridge PArkwway... Kept it to 3K Rpm (a little more.. .a little less) for a few tanks

Got almoist 38 MPG... followed by a 35 MPG.

Right Wrist has A LOT to do with MPG.

That is not to say we didn't flog it a bit... just not living above 3,500 (or 5,000) Rpm as the norm.

[8Track]

I have a 99 standard, 30,000 miles, no modifications. It consistently returns 36mpg no matter how its ridden.