Fuel UNefficient

[kevingkruse]

So I just recently replaced my butterfly seals, mixture screws and o ring, and enrichment seals, and my bike runs a lot better. However, I just found out I now get about 125 miles per tank, I know this because I just ran out of gas! Luckily I'm right next to a gas station. But before I replaced those things, I was getting about 190 miles per tank, pretty big drop. The only thing else I did was lower the float about 1mm. I have a little more open exhaust from mikesxs, stock air filters, mixture screws at 3.5 turns out, and I have not changed jet sized at all upon having this bike. I'm going to tinker around but I just thought id share that, if anyone has any input, that'd be cool.

EDIT: if my pilot jet plugs somehow came loose, would that be drawing in and burning a lot more fuel? I looked at my plugs after doing the replacements and they don't look TOO black, but they're not perfect.

 

[16VGTIDave]

I'm getting about the same range from my Maxim. I'd guess that by replacing all the worn seals, you eliminated a number of small vacuum leaks and are now drawing more fuel through the carbs. Lowering the float levels would slightly reduce the fuel delivery. The exhaust flowing better would have the engine breathing better, which would increase power and fuel consumption when you are twisting the throttle.

What jets are in your carbs? Where are the needles set?

Dave

 

[kevingkruse]

My needles don't have any notches and my jets are;
Main - 135
Pilot - 42.5
Air - 155

 

[16VGTIDave]

Nothing extreme there, certainly not as large as the jet's I'm running (155 Main, 47.5 Pilot), but my mufflers are virtually open and I have pods.

Give it a week or 2 and see if it improves. With the better performance, you are probably twisting the throttle more than you used to.

Dave

 

[kevingkruse]

Maybe, I did do two 25 mile freeway trips on this tank and I was doin 80 the whole way but I didn't think it would give me that low of mileage

 

[16VGTIDave]

50 miles at 80 MPH? That is certainly going to kill your mileage! Our little motors are working hard to run at that speed. There is nothing aerodynamic about our bikes, so the faster you go the more your fuel consumption will increase, exponentially! I have to wonder how much oil did you burn on those runs?

Try the same trips at 60 and see what happens. Then try 55...

Dave

 

[Scorpio1963]

what does your exaust pipes look like?does it look black and sooty inside?What color are the plugs they should be whitish. 3.5 turns on the mixture screws sounds like too much.80mph whats the speed limit?LOLTRY @ 65 mph turn your pilot screws to 2 3/4 turns and adjust till your idle either increases or decreses.when it starts to increase the idle and its running smooth your there.How many rpm @ 80mph?

 

[Lou Ranger]

According to the manual, your SG/G has a 14L tank (3.70 US gals), which coincidentally is the exact same size as the Maxim tank.
I can consistently go 235 kms (146 miles) until I have to switch over to reserve after using 11.7L (= 2.83 US gals). A number of folks have posted on various threads regarding their mileage and I don't recall anyone (with a well tuned bike) reporting mileage that differed more than a half dozen miles plus/minus.

125 miles seems pretty low, but 190 miles? 190 sounds crazy high (even for a Maxim ). With my mileage, if I ran the tank to completely empty, I would be able to get 281 kms (= 175 miles) before having to walk to a gas station.

 

[kevingkruse]

Its kinda hard to look inside my pipes so I donno, my plugs are kinda white at the tips but black everywhere else, but not caked. My tach is busted and super jumpy but I'm thinking its about 6.5 @ 80mph, I might be goin a little over the limit . Before I got my new pipes and seals I tested my mileage and it ran dry at 190, I must of been takin it super easy. After I got my pipes I, luckily, ran out of gas at a gas station at about 175. I do remember when I put my carbs back together that my pilot plugs were a bit worn and loose, I want to check if they fell out or somethin.

 

[Lou Ranger]

... After I got my pipes I, luckily, ran out of gas at a gas station at about 175 ...

Ahh, so when you say 190 (then 175), you are talking about the entire tank, including the 3/4 gal reserve. If that's the case, then it sounds like you had it running pretty optimally and 190's not so crazy.

I've never cruised above 60 mph on mine, but when my ear got used to the high revs and my skills improved enough to do more shifting and accelerating out of curves etc., my mileage went down nearly 10%. I imagine a long trip at 80 mph would knock off another 10% at least.

Still not all the way down to 125 though. Any chance you used a different brand of gas or the gas pump shut off prematurely

 

[Scorpio1963]

My milege is not so good but I ride my bike kinda hard and mostly all in town.Plus I have problems with my plugs and carbs so thats self explantory why.Next spring the carbs will be fresh my exaust will be modded they are open right now.I hope to have pods also.My valves are out of adjustment and I know that needs to be fixed.

Your exaust should be grayish some what dark but not totaly black.Your plugs should be white all the around the tip on on the elctrode on top of them also.

 

[kevingkruse]

Sorry, I forrgot to say my reserve doesn't work, it doesn't have the tubes in the petcock going into the tank, so all my numbers are the whole tank. And as a matter of fact, on that 125 mile tank, I used for the first time premium gas, instead of regular.

 

[Tombo]

Where did you get the butterfly seals?

A drop like that demands a retest. My guess is that the bike should cruise at 55 for optimal fuel economy. Cruising at 8000 I'd WOT on these little guys! Retest at speed limit, and really stick to it, try not to be more aggressive than you need to be to be safe.then calculate . Then retest to confirm your results.still not scientific, but a bit more precise than WOT! (but much less fun, of choose )

 

[kevingkruse]

Got the seals from mikesxs. and I'm in the process of takin it easy on this tank to see what I get. But when I was cruisin at 8rpms, the throttle was only a tad past half way, so I wonder what mileage I would get if I was WOT for like 25 miles?