32 mpg... kinda bummed

Bminder · October 31, 2014, 04:46:41 PM

So I thought I was getting 35-38 mpg based on rough guesses in the past.
Then a couple weeks ago I filled it up completely and ran it to the empty point it was before I filled it. It looks like I got about 32 mpg on this tank.
About 150 miles.
All town riding, under 40mph for the most part.
Oh well. Better than my '02 Ram 1500 that gets 12 on a good day.

Capn Ron · October 31, 2014, 05:52:37 PM

Hey Billy!

This is an issue I'm also having at the moment. On my big trip, I stopped for fuel 128 times in 85 days and always checked mileage. My worst tank was 38MPG and my best was 52MPG with an average over 17,000 miles of 44.5MPG. I racked up another 5,000 or so miles and then made two changes: Valve shim adjustment (they weren't far off) and swapped the 37.5 pilot jets for .40 pilot jets. With the pilot jet change, the bike starts and idles MUCH better, but my fuel mileage is now way down!

On my trip to Reno and back, I couldn't break 35MPG no matter how I tried. Two tanks were at 32MPG (one included a VERY high speed desert run so I understand that)...It's baffling! For me, it's not as much a cost issue as it is a range issue! I was on fumes at 180 miles.

I'm thinking of going back to the 37.5's just to test this theory before I start fiddling with other carburetor adjustments.

Bminder · October 31, 2014, 07:55:34 PM

Hey Ron!
I've got 40's in mine now too. Plus we're at 6200 feet elevation which sucks power and economy.
Thought I was getting a little better than 32 tho.
I'll keep checking it and see how it goes.

FJmonkey · October 31, 2014, 09:12:27 PM

Cap't Ron, I have #40's in and made the run up to visit Randy at RPM on the slab early this week. Having the new RPM exhaust and not slabbing it for some time I was not sure if my range changed. So I made sure I checked my MPG at the first fuel stop. I was running with the traffic at speeds between 70 and 80 MPH. This included going up and over the grapevine. I was getting 42.3 MPG. I have not checked my other fuel receipts yet but I expect it to vary +/- 5 MPG. 42.3 x 4 gallons gives me 169.2 miles with 1 gallon in reserve. Perfect, that is what I am accustom to getting on my past long trips. I don't think your pilots are the source of your woes. Besides, think about when your pilots are working....

When do we ride or sail?

Capn Ron · October 31, 2014, 09:27:18 PM

Yeah, Mark...I thought about you and your bike when trying to get my head around this horrible fuel mileage. I know you're running 40's too and are higher-geared than I am...and typically carry more speed into corners than I do...Not sure what other carb changes you've made... That being said, the pilots are the only thing I've changed. Might be more there that I need to fiddle with, but it's exactly the reason I don't like making changes. Starts me down a road of chasing the right balance and I have too many engines in my life to keep up with as it is.

Going to change back to 37.5's to see if that's the difference.

Call me tonight if you want to sail on Sunday...

FJmonkey · October 31, 2014, 09:42:46 PM

Quote from: Capn Ron on October 31, 2014, 09:27:18 PM
Going to change back to 37.5's to see if that's the difference.

Call me tonight if you want to sail on Sunday...

Ok, I will call to set up a sail date. In 3 , 2, 1....

simi_ed · October 31, 2014, 10:28:53 PM

Ron, before you swap out the 40s, maybe you should do a baseline run to get a before mileage, then swap & do the same run to see if there's a real (and worthwhile!) difference. I know I paid a small mileage penalty, but the throttle response made it a good trade, IMHO.
YMMV

Capn Ron · October 31, 2014, 11:20:20 PM

Quote from: simi_ed on October 31, 2014, 10:28:53 PM
Ron, before you swap out the 40s, maybe you should do a baseline run to get a before mileage, then swap & do the same run to see if there's a real (and worthwhile!) difference. I know I paid a small mileage penalty, but the throttle response made it a good trade, IMHO.
YMMV

I might just do that tomorrow...You up for a ride? Coast up the 33 past Ojai?

simi_ed · November 01, 2014, 12:00:41 AM

Sorry, full day including a visit to the KTM dealer for a warranty rear MC, then babysitting. Maybe another time?

Capn Ron · November 01, 2014, 12:12:07 AM

Always down for a ride with you my friend!

I'll do a 200+ mile day tomorrow and report back the numbers.

racerrad8 · November 01, 2014, 12:20:05 AM

Quote from: Capn Ron on October 31, 2014, 09:27:18 PM
...Not sure what other carb changes you've made...

Those are a set of carbs I built for Flynt, for his first FJ I believe 5,6 maybe 7 years ago, plus he is running RPM pod filters.

The pilots should not really affect your highway miles unless you are rolling on & off the throttle and getting the carb back into the pilot circuit. I am going to venture to say your emulsion tubes and needles are worn and the fuel mixture in the cruise range has enrichened.

There could be other things like float level, plugged/restricted emulsion bleed jet, dirty air filter...

I can always get them built & dialed right in for you and all you'll have to do is the blip test and you too can get great MPG.

Randy - RPM

News:

32 mpg... kinda bummed