Tuning for mileage

[[email protected]]

Fuel mileage is a pretty common subject on the site here and it seems that 40mpg is the benchmark to hit. I did achieve that on one ride last year, but that was with a totally different setup. This year I got 38mpg once while riding VERY conservatively but most of the time I only get 30mpg and am thinking I should be getting better than that. I see the low fuel light around the 83 mile mark on average.

This year, I ended up with a different exhaust, different set of carbs, different vboost assembly and some other parts are different as well.


Old school hindle 4-1. Seans jet kit. 155 mains. Stage 7 needles. Clip is on 4th position (from pointy end). Stage 7 springs. Slides drilled. Stock PAJ. Floats set correctly. Carbs synched. AF screws at 3 turns out. Have to run the vbooost open or closed. The controller doesn't work. Its hooked up to a 3 pole switch. I run it open once the carbs are synched.

Bike runs fine, no issues anywhere. Seems just a touch down on power compared to old setup. Only reason I say that is that its not as easy to wheelie as it was.

Plugs look good. Porcelain is light tan with a touch of red from additives.

So, to try and get better mileage, I tried to lean the needles a touch. I raised the clips from 4th slot from the point to the 5th slot. The bike ran like complete crap in the low/mid range like this. I made it 5 miles down the road and had to turn around it was so bad. Once I got past 5k rpm it was fine but from 2.5-5k it wasn't right. So, I put the needles back to the 4th clip and left them there.

So, my question is, where do I go from here to try and get better mileage? I can't lean the needle one clip. I don't think the mains will make a huge difference will they? Carbs are synched. FA screws are only 3 turns out. Just looking to get some more miles out of a tank. I can't see open vboost sucking that much extra fuel???

 

[maleko89]

Are your floats all 17? Valve adjustment? I'm running Mikuni 177.5's in PAJ2 which lean out the idle circuit. Perhaps coasting enrichener is stock closed?

What air pressure you running in tires? Are brakes dragging at all?

 

[gamorg02]

i'm about sea level.

morley kit
vboost always on
2.5 shims on stage 7 needles
stock springs
177.5 PAJ2
152.5 jets (stock i think, right)?

try that maybe?

also make sure ur a/f screws are set for vboost always open.

 

[vmaximum]

buy a harley? :rofl_200:

 

[gamorg02]

i get between 33-42 with that config. got 42 on one tank to pittsburgh, but normally mid-30's

 

[[email protected]]

Are your floats all 17? Valve adjustment? I'm running Mikuni 177.5's in PAJ2 which lean out the idle circuit. Perhaps coasting enrichener is stock closed?

What air pressure you running in tires? Are brakes dragging at all?

floats 16-17mm
never checked valves. Bike is an '06 with 6K miles
Never checked coasting enricheners
Tire pressure is 44psi front, 42 rear
Wheels turn fairly free when on the stand. You can hear a slight bit of drag up front but not enough to warm the rotors up or anything.

i'm about sea level.

morley kit
vboost always on
2.5 shims on stage 7 needles
stock springs
177.5 PAJ2
152.5 jets (stock i think, right)?

try that maybe?

also make sure ur a/f screws are set for vboost always open.

Sounds real close to my setup. I'm leaner on the needles (4th slot) and richer on the mains (155's). A bit higher than you but not much (1200')

Have you found that with open vboost you can lean out the a/f screws more than with functional vboost? I'm set at 3 turns out right now.

It runs fine everywhere and the plugs look good. I'm half thinking don't F*&^ with it, half thinking I need too, LOL

 

[gamorg02]

Sounds real close to my setup. I'm leaner on the needles (4th slot) and richer on the mains (155's). A bit higher than you but not much (1200')

Have you found that with open vboost you can lean out the a/f screws more than with functional vboost? I'm set at 3 turns out right now.

It runs fine everywhere and the plugs look good. I'm half thinking don't F*&^ with it, half thinking I need too, LOL

i'm 2.5 from the blunt end so its pretty lean on the needles as well...

i had the a/f screws done with an a/f sniffer and set. it took us like 30 minutes per side as the vacuum is weird with 2 carbs.

 

[tugla]

4 into 1 kerker
stg 7
vboost open(actualy removed)
clip on 4th from point(ran better mileage on 3rd)
152.5 jets
2 1/4 turns out

gets about 39-41mpg at 75mph, plugs real nice color, seems still a little fat at the top of mid range but with that kind of economy i rather not mess with it now, maybe at the end of season