Carburation Issues

[L J VFR]

Since adding the Vance and Hines exhaust I'm having issues with my carburation.  My plugs show lean.   I have k/n,  3 total shims,  108 mains, with 3-1/4 turns out and stock  40  pilot jets.  The bike will fire up with no choke on a cold start. The bike has lost some bottom end but I anticipated this due to the non restrictive freer flowing exhaust. The bike runs strong everywhere else in the rpm range.  I understand that everyone will say to go to 42 pilot's and even increase mains to 110-112-115.   My fuel mileage is poor though now at  38-42 .  If I am running this lean, shouldn't I be getting better than this??  Chad in michigan says he gets 45-48 when easy on the throttle.  And this is with 112 main jets and 45 pilots!! 

So my question is:

A) What do you think about tossing the k/n and putting a factory filter back in?

B) Do you think adding 42 pilot's will solve my lean condition?

C)  Opinions or suggestions??


Thanks in advance, Lance

[TLRam1]

Do you have photos of your plugs?

Different scenarios you can try are

42 pilots

Fuel Screw - 2.5-2.75 turns out

Mains - 110-112 mains

Needle - drop down to 2 shims that maybe give you .040 or a combination that gives you .050 lift.

Where you run the bike most of the time is not middle to wide open so increasing Mains should not kill your mileage unless you run WOT often and in the twisties of AR, I doubt that. 

Putting in the stock filter I would probably keep the same settings because where you are running most of the time is below 1/2 throttle and airflow will be close to the same I would think or at least not that much difference.

To me 38-40 MPG is pretty avg., maybe your twisting the throttle for a little more thrill and sound with your new pipes!   

[Chad in Michigan]

didn't i write you back lance? i thought i did but maybe i forgot.. i also have the dyna 3k and that is supposed to bump up your fuel mileage too with the advanced timing curve. also, what sprockets are you running? yeah last year i had the 112 mains/45 pilots/3 turns out and 3 shims and most of the year i rode with a 15 tooth up front/ stock 40 in rear. i was rich on the low end and possibly the midrange by a touch. don't get me wrong, it rode great for the  most part, but i did notice that it fired up with no choke and ran great right off the get-go and the plugs were a little sooty and so were the exaust tips. the best i got when babying it was 45 i think. but that was tooling around at 55 or 60 and stop and go in little towns last year. i dont remember getting 48-50 since i starting tinkering with it. i remember when it was stock it would get that most of the time, but it was real lean. right now, i am running 115 mains, 45 pilots, 2 shims and 2.5 turns out. plugs are correct color, when running 55-60 with the 15 tooth sprocket i get about 42 mpg. we took a ride last weekend out to the thumb of michigan, and riding it 55-60 and a few hard off-the-line jumps i still hadn't hit reserve at 91 miles, i think it took 2.1 gals to fill up to in the neck of the tank area. if i get on the throttle and speeds of 80-90 constant on the highway, i got 24-28 mpg. i'd say your plugs are showing lean due to the main jet not being big enough. i remember that from my plugs too.
i'd try 110 or 112 mains, 45 pilots, 2 shims, 2.5 turns out. that way, the larger main will allow more fuel to flow around the needle at low speeds, even with one less shim, and more fuel will flow from 2 of the 3 holes on the pilot jet when you crack the throttle and the 3rd hole from the pilot is your idle mixture and is controlled by the 'd' screw. i had the 110 mains but wasn't happy with it either, but like i said i have the dyna 3k and coils and maybe that makes a difference somehow. i'd hate to tell you to go with the setup i have and have you be too rich because i don't know how the dyna stuff makes the parts react. i wish there was a perfect setup for everybody. i've spent alot of time on mine making it the way i want it, i know it's not perfect i think its pretty close. i can only suggest things to try. i should have written everything down step by step and noted all changes too.. oh well. hope you get somewhere with all this

[Greg Cothern]

I personally would install the 42 pilots, stock shim plus one additional, adjust the pilots out to 3 1/8 turns out, and 108 (or the 107.5 whatever they are) and GO!!!!

This is what I feel would work in your situation.  Although in the 50+ carb adjustments I have done I have not went this far with one YET!  Working with a MOOT'ster on their setup adjustments to try this one. 

From what I have seen in the past etc I feel this will be a VERY good setup for K&N and Free Flowing exhaust..

[Chad in Michigan]

greg, if you only knew what a little more gas could make those bike feel like...

[L J VFR]

Thanks for the replies everyone, do appreciate it.  I guess I will go and order the 42 pilot jets from honda today.  I just was'nt gung ho about pulling the carbs again but I will.      Sorry Terry, no pictures.  No computer at home, all my web blogging comes from work.  But the plugs are pretty white, no brown or gold color to them all.   Thanks again everyone.

[L J VFR]

Stock sprockets Chad.  Thanks!!    110-112 mains, huh,  let me ponder that a little!

[Chad in Michigan]

i've also found out that i should let the bike warm up a little before trying to pull the carbs off. maybe it was the chilly michigan air, but they tend to come off alot easier when the bike is cooling down from a short ride.

[TLRam1]

i've also found out that i should let the bike warm up a little before trying to pull the carbs off. maybe it was the chilly michigan air, but they tend to come off alot easier when the bike is cooling down from a short ride.

Haha-----Probably that, in Texas we don't have the same issue. lol

[TLRam1]

Stock sprockets Chad.  Thanks!!    110-112 mains, huh,  let me ponder that a little!

I hear ya, I don't have the experience Chad does in the upper ranges, yet. If you go up in Mains I think that would enable you to drop a shim and keep your midrange tuned.

[Chad in Michigan]

i also noticed if your a heavy dude, like me, lol, that i get better mileage in town, driving slower with a 15 tooth sprocket. it allows me to creep along in 5th or 4th thru the little towns at 25 mph or so and not have to keep the rev's up a little bit higher in 2nd or 3rd. with stock sprockets, i couldn't do 25 in 5th gear without it wanting to sputter out and die if you get on the gas just a little bit. it also gets the rev's up quicker, where the bike loves to shine. i put stock sprockets back on for two weeks last month, and i liked it, but not as much as the 15/40 or the 16/43 combo i have on there right now. it's just more sportier with those sprockets.

[Greg Cothern]

Chad I have felt what K&N, Megaphone mufflers, 45 pilots, 110 mains, and extra set of shims feels like and I personally COMPLETELY FEEL that it is over rich.
This particular bike's fuel economy fell off around 18%, it was falling on its face (not horribly) on the low end unless you spun it up beforehand.  Mid was decent, top was ok.  It got better when 42 pilots were swapped for the 45's, the fuel economy came back up quite a bit and the performance was better on the low end and the mid to high is still about the same.  So that alone says the 45's are too much (albeit dont have a Dyna ignition unit to use so that certainly comes to play here, I am searching for one for my 96 so can play with it when I find one).

I have on my yellow 96 the dyna-jet kit with the advanced needles etc played with it some and richened it up and it hurt the performance terribly..  Throttle response fell off bit time, and in the midrange if held there would try to foul the plugs..  Had to keep it revved to keep it clear. 

THAT was all just from moving the needle clip position up 2 spots.....  OH I have K&N, Supertrapps (which from my experience seem to flow EXTREMELY WELL), 40 pilots (which I do feel need to be bumped to a 42), and 100 jets (keep in  mind though the needle is VERY different, although I need to order in some of dyna-jets main jets as I do feel this setup is a bit lean on top end, so I feel a 102 dyna-jet main would be the ticket).

[L J VFR]

Thanks for the info Greg.  So you think I should not add the 110 mains, keep my 108 mains and just install the 42 pilots?    Trying to keep up here.       Also, a side note, Honda charged me $16 a piece for the pilot jets.      I sure hope it works!!!

[Greg Cothern]

I do Lance, I feel you will be about right with the 108's and the 42's..

[L J VFR]

Thanks.