MPG

[revschuette75]

Ok, I put on different exhaust, Barons Double Nasty pipes, put on the K&N filters, had the dealer rejet and repin the carbs (said it had to be done). Have any of you done this and what did it do to your mpg? Just wondering if anybody else has done this or not. My mpg has dropped from 44 to around 32 I'm thinking. Guess I'm just wondering if something could be wrong or if this is just the price I pay for putting on different exaust? Thanks for the feedback.

[Darren]

I have screaming eagle pipes and K&N filters with original jets and run 40-42 mpg. I have not noticed any difference on the plugs (not lean) and runs just fine. All except a 'little' louder:thumbsup2::thumbsup2:

[BOO]

I don't believe anyone rejets these bikes, they seem to run fine with the original jets.

Do a search on this forum and I think you will find all kinds of info about jetting.

Sounds like the guy put bigger jets in and causing your bike to run rich AND causing your gas mileage to take a dump.

BOO

[RandyR]

You got taken.

[Seaking]

I put K&N filters on my bike, the OEM's on this used bike were shot and I got a set of K&N's at such a good price I couldn't pass them up..

 

Then tried different set of pipes here and there from Road King take offs to Larossa to Rineharts.. My oem pipes were tossed long ago as they were damaged and not looking pretty. At no time had I had to 'rejet' the bike.. seems to run fine without being too lean or too rich.. What affects the bike mostly around here is the temp and humidity...

 

As far as MPG goes, I can honestly say that with the more open pipes and K&N your mileage will go down some.. Because you have louder pipes, you might have a tendency to blip the throttle more, come onto the throttle more and be heavier on the throttle than before.. that contributes to some of the lower mileage but also you have a more open system.. more air in, more fuel to mix it up properly and pass through.. thereby more fuel consumption. (something like that)

 

As far as how much fuel mileage you should be getting? Hard to tell.. I know that on the recent road trip, we did our mileage calculations at the end of the day and it varied from 32 to 54 mile to the gallon.. Mostly dependent on various factors such as head winds, terrain, types of roads and traffic and speeds.. Going through the 400 miles of the Blue Ridge Parkway we were getting anywhere from 44 to 54 miles to the gallon, depending on we were riding.. but it's mainly all 3rd or 4th gear and some nice gentle slopes.

 

On the open slap, interstates and such, screaming down at 70 to 80 mph (true speed), the mileage dropped down into the 30's MPG range.. Slower IS better on these bikes..

 

I can never get better than 40 mpg around here due to the hills, high winds and such.. but its all on how you ride.. If you ride MPG conscious, you can get some great numbers.. but if you ride it like you stole it, and enjoying the bark of the pipes and the noticeable oomph the air filters and pipes combo give you, then you're gonna get lower.

 

I'm currently running with Road King pipes as they are quieter for long hauls, but my buddy rides with more open and much louder (too loud?) Larossa pipes.. And our burn mileage always match within one or two miles to the gallon..

[twigg]

All that being said, it's pretty easy to check that the size of the main jet is correct.

 

Just do a "throttle roll-off test".

 

Mark the throttle at WOT, 7/8 open and 3/4 open.

 

Get the engine good and hot then find yourself a nice open piece of highway.

 

Run the test in 4th gear. Running it in top gear will have you doing some very illegal speeds.

 

Accelerate the bike until it is pulling well. Crack open the throttle to about 7/8 open. That gets the motor running on the main jet. When the revs are climbing high, and the bike pulling strongly, snap the throttle back to 3/4 open.

 

When you do that, the bike should simply pull less and begin to slow, or accelerate less hard, but do it smoothly.

 

If it "surges" a touch, before settling, the Main Jet is too small. If it "stumbles" then settles then the Main is too big.

 

If everything is smooth then the jet is correct, or close enough.

 

This happens because snapping shut the throttle shuts the air down faster than the gas. If it was running a bit lean (jet too small), then it will briefly richen and you get the surge.

 

If it was running rich (jet too big), it will over richen and stumble.

 

If it does neither, then it's pretty close.

 

A dyno session will be quicker, more accurate, but cost quite a bit.

[Freebird]

Re-jetting is absolutely not necessary. I've run exhausts that were stock, modified stock, Samson, Khromewerks, Road King and then to stock again and none required that I re-jet the carbs. Most of the folks that I know who have been talked into re-jetting have seen decreases in performance and in fuel efficiency.

[flb_78]

The K&N's and mufflers will not affect gas mileage. The restriction on the intake side is the air box on top of the carbs and the pipes leading to the filters. You could probably remove the air filters completely and notice no difference in performance.

 

On the exhaust side, the head pipes are the restriction, not the mufflers.

[revschuette75]

Ok, I called the dealership which did the work and asked them what I should expect of mpg, they said a drop of 4 to 5, but then a bit later the guy said one guy they no didn't experience a drop at all, still getting around 42. I did find out they didn't rejet, they shimmed the needle and adjusted the "air screw?" I think thats what he called it, well to adjust the mixture I guess. He told me to run some of that ring frre that Yamaha sells and see what that does. I did expect some of a drop and yes realize that at first I would be hard on the throttle, but this past weekend did baby it and it still seemed to be less then what they said I should expect. I love the pipes and the sound, but when going long distances it just doesn't pay, at least strating to think it doesn't.

 

By the way, I do notice that the throttle response is much greater.

As for the terrain, it was mostly flat county roads.

[BuddyRich]

You traded off mpg for power. No way around that usually.

[pegscraper]

...had the dealer rejet and repin the carb...

 

What is repinning the carbs?

 

And like has been said, his rejetting is way too rich. You can still get better mileage than that.

[revschuette75]

Pegscraper - I meant shimming the needles, my mistake.

[bongobobny]

Yah! You're not the first to notice a reduction in MPG with the K&N's...