I had my Evo dyno-tuned. The Indy installed a DynoJet kit because he didn't recognize the needle/needle holder installed and he want to "start fresh". There was already a Thunderslide in it.

Well, the throttle response is good, but the mpg's are 35, 37 at best! I also get some decel popping, but only when the throttle is closed. I think he jetted it on a 42/170, based on the remaining jets I have from the kit. This is on a stock Wide Glide + high-flow a/c and Khromewerks mufflers. Stock cam, stock.... etc.

I don't need to race. I really don't ride it very hard at all. But I do plan to make some long trips and under 40mpg without a passenger or luggage on a Dyna is not acceptable to me. My dad's stock 89 Softail gets 50, so I have mpg envy!

Should I buy new stock slide, needle (plus a couple washers), needle holder, and toss the DynoJet kit and Thunderslide in the trash? Or is there a way to make this kit work with 45+ mpg results?

 

The whole problem with dyno tuning ...is most of the time they are just shooting for maximum horsepower...without taking drive-ability or MPG into account...I would take it back... tell the indy you are dissatisfied with the results, and why and see if he offers to "tweak" it...probably only need to go down a jet size or two to get where you want to be .

 

I get around 40mpg / ev27 cam / e-shorty carb with thunderjet / dyan single fire / thunderheaders. Something is not right if your only getting 40. When you play with the jets, with out caming it you realy don't do any good. Go stock or just a stage 1 kit . The guys i ride with know I need gas before they do, its not realy a hot rod, just sounds like one.

 

The dynojet kit IME will not optimize mpg. The emulsion tube in the DJ kit is the reason IMO. You can try to adjust the needle to improve the milage but risk being too lean in the cruise range & that could cause damage. Take it back...

 

I took my Dyno Jet kit out because it gave good power and crap MPG..I like rideablility so I put the carby back to standard and jetted it 45/195 with a spacer under the needle....perfect!!! Even with the EV27 and high-flow aircleaner it still gives good mileage (48mpg).

 

I can't imagine you would go any smaller than the 42/170 you have in there now. Geez, I'm running 45/185 and my mileage is in the low 40's. Gotta be the emulsion tube as 05FLHTC said. Or their needle.
I used a kit from these guys on both my FXR and my Sportster and was very happy with the results. The EZ-just mixture screw makes dialing in the idle mixture a breeze.

http://www.cv-performance.com/

 

I have the dynojet and thunderslide. I get 46mpg or better with 48/180 jets. I was getting even better than that, but my EV27 knocked the mpg down a tad. I can't believe your getting that low mpg. When I first installed my cam I was down to 41-42mpg, but once I was able to stop slobbering on the throttle I have been averaging the 46ish as mentioned. Could it be something else than the carb jetting?

 

Well Bikerlaw, I'm all ears as to what direction to go. I'll try a call to DynoJet and see what they suggest. My Indy doesn't seem to know either, since he only "tunes for performance".

 

OK, what about the air filter element itself? Is it old and clogged? Doesn't take long for a high flow unit to plug up. That will hurt mileage. Have you actually pulled the float bowl to verify the jetting? What if the one's missing from your pack are 50/190? That would SUCK fuel. Are your tires low? Tires just 10 lbs under inflated will cost a bike severe mileage drops. Just brainstorming here.

 

I tuned , timed the old evo, all by sound & feel, hot & cold , starting , and putting the hammer down on it. Last summer the dealer had a free Dyno test, so what the heck. 67hp, 76tourqe. Flat lined the air/fuel mix.
ev27 / E, shorty/with thurnderjet carb tuner / dyna signle fire / and them loud a$$ Python Thunderheaders. If I stay out of it {not} I can get 43-45