OK Gas milage...

[mcgovern61]

joedrum » Wed Sep 27, 2017 3:21 pm[/url]":2rlynzvg]
My biggest problem doing this is to actually look at mileage on the second fill up LOL....sometimes I can go about 5 tanks before I put both steps together....

That's ok Joe. You are practicing that new math! :smilie_happy:

For me, I fill the tank up to the bottom of the gas tank neck, set the odometer to zero, ride til reserve is needed and then go and fill the tank again. I then check the gallons in to fill to the bottom of the neck again against the actual miles on the odometer.

 

[Ansimp]

mcgovern61 » Thu Sep 28, 2017 7:29 am[/url]":157saei1]

joedrum » Wed Sep 27, 2017 3:21 pm[/url]":157saei1]
My biggest problem doing this is to actually look at mileage on the second fill up LOL....sometimes I can go about 5 tanks before I put both steps together....

That's ok Joe. You are practicing that new math! :smilie_happy:

For me, I fill the tank up to the bottom of the gas tank neck, set the odometer to zero, ride til reserve is needed and then go and fill the tank again. I then check the gallons in to fill to the bottom of the neck again against the actual miles on the odometer.

:good: :yes:
The only other thing that I do is to always fill the tanks while on the side stands if I am trying to get consumption readings.

 

[frankroche]

OK bought fuel (early) and took 2.8 gallons 89 miles on trip odo.
The math says 31.47 miles per gallon
kind of low, not near as good as my car (Prius)
That done the guys that say do the math should be happy...

 

[desertrefugee]

lol. Well, Frank, being "one of those guys" we can now get hopefully down to business. You're right, that's probably 20-25% lower than it really should be. The thing is, you're reporting that it's running well from idle to overdrive. My first thought would still be some sort of restriction to the air flow, but you have a new air cleaner and have verified that the choke is opening up completely. Synchronization issues would contribute, but you've gone there, too.

I do wonder about the needle shimming you mentioned. That'll really affect mileage. You might want to revisit and, perhaps, return the needles to stock height.

 

[frankroche]

desertrefugee » 24 minutes ago[/url]":3vkbavug]
lol. Well, Frank, being "one of those guys" we can now get hopefully down to business. You're right, that's probably 20-25% lower than it really should be. The thing is, you're reporting that it's running well from idle to overdrive. My first thought would still be some sort of restriction to the air flow, but you have a new air cleaner and have verified that the choke is opening up completely. Synchronization issues would contribute, but you've gone there, too.

I do wonder about the needle shimming you mentioned. That'll really affect mileage. You might want to revisit and, perhaps, return the needles to stock height.

I'm wondering about lots of things, like needle shimming and even if my foot is spending time on the brake unknowingly!
The shimming was suggested by Mike Nixon who was helping me diagnose and fix "backfiring" while warming up and it causing stumble while transition from idle to upper circuits (in the carb). I was stumbling while trying to drive about town and accelerating, enough to make it an issue.

I suppose I could unshim and see how it is now....
Any other ideas (yes i know pull the plugs and read)

 

[mcgovern61]

Mike is a pretty sharp guy and very helpful for sure. But I am not sure shimming to fix a backfire condition is right. I will most likely have to hold out any further advice because my work has only been on the 1100 carbs and only in complete stock condition. I found out how to get them to run with proper cleaning, sync, rebuild and settings. But, that is my limit and I really do not know about the 1200 carbs.

I do know that if properly setup and working correctly, the '84's normally get 40 MPG average.

 

[frankroche]

Well it's an 85 but that should make no difference..

 

[Ansimp]

Mike Nixon knows carbys! :yes:

 

[slabghost]

Are the mix screws set at nominal book setting or did you set them after you got it running? If they are set too rich that could be all or part of your mileage problem. To set them right you need to start with the motor warmed and idling at 1000 rpm. Pick one carb and adjust mix screw to highest rpm possible. Reset idle to 1000rpm and set next carb mix screw for highest rpm possible. Continue through all 4. Then do them all once more the same way. See what you have in performance and mpg after.

 

[dan filipi]

I’m noticing a drop in mpg on mine lately. Where I used to get 40+, or at least 38, I’m getting low 30’s. Wonder if the gas has something to do with it?

 

[desertrefugee]

I got 42 MPG on my '78 today running up to the Payson Airport restaurant for lunch. Pretty much where it's been for the last three years. So, I don't see a noticeable shift here in Arizona.

 

[frankroche]

Got the bike running and in great shape. First sync I did, I turned them all in counting the turns and set them at 2 1/2 turns, it ran pretty good.

 

[slabghost]

Wrong place for the mix screws.

 

[frankroche]

OK where do you think is correct?

 

[slabghost]

As I described above. Set each carb to highest rpm.

 

[cowboy45]

I had set my 81' gl1100 to 2.5 turns and it turned out to be too rich. It was using more gas and smoking a bit. I returned the mix screws to 1.25 turns (which is the book settings for my gl1100) then I started getting much much better gas mileage and it stoped smoking.

Sent from my Moto G (4) using Tapatalk

 

[frankroche]

OK so I turned the warm idle uo to 1000, turned each screw, one at a time, till it was closed then turned them out till the RPM increased then turned the idle back down to 1000. Went around and did it twice. Very interesting, i would turn the mix screw and the idle would go up and if I kept turning it up the idle went back down. So each screw had a spot where the idle was high and either side would be low. Didn't count the turns. Well see if the milage goes up, down or stays the same!

 

[slabghost]

yes the correct position is where turning either direction decreases rpm.

 

[D-50Dave]

dan filipi » October 1st, 2017, 8:36 pm[/url]":u1oz43e4]
I’m noticing a drop in mpg on mine lately. Where I used to get 40+, or at least 38, I’m getting low 30’s. Wonder if the gas has something to do with it?

I know, here in New England, my milage on all vehicles goes down when the "summer" gas gets switch over to "winter" gas; down about 10-15%. FWIW, Dave

 

[frankroche]

Hopefully this weekend I will get the figure since turning the air mixtures...

And I found out both tires were down about 10 to 12 lbs (got a new gauge that works on the tires/wheels/stems)...wonder what this does to mileage? I know on my car 33 vs 40 lbs makes a 5mpg difference (its a Prius).