Fuel consumption

[casper]

Good day.

I would like to know, what is the Ave fuel consumption is that you guys are getting on the 1100s. Mine, I don't think is right. I get 14Km to 1litre of fuel. That is about 8.75miles to 1 litre or 192miles on 22litres of fuel. This is with city riding, but I must point out that I am riding it like a angel, not exceeding 4500rpm once throughout the entire tank of fuel

What can be done to make this better? Lol carbs were already synced.

Also, what octane fuel is best to use?

Thanks guys

[great white]

You'd probably get better responses if you stick to MPG or L/100kms. You've got quite a few different measures in there.

My fj12 isn't that great on MPG either. Mid to low 30's on a good day.

Around town riding has me looking for fuel around 150-180 kms.

My bike also has high kms (~145000) and I suspect my needles and emusion tubes are knackered. This can cause poor mpg and ridability issues.

Cheers.

[Bones]

From full to empty on the gauge and with the fuel light starting to come on, I get around 300 km, takes about 16 litres to fill it back up to full,  sooo... that works out to roughly 18 km per litre.

[roverfj1200]

My 88 1200 gets 16.5km per litre and close to 17km per Litre 2 up.

pull the carbs and clean them well and set the float levels a few millimetres lower than stock to lean it up a bit..

[the fan]

For the math impaired here in the USA

1 liter = 0.2641721 Gallon
1 gallon = 3.785412

1 KM = 0.6213712 mile
1 mile = 1.609344

1 mpg = 0.425143707 Kilometers per liter
1 KPL = 2.35214583 Miles per gallon

For reference:
Roverfj1200's 16.5-17 KPL = 38.8 - 40  mpg
Caspers 14 KPL = 32.9 mpg


You UK folks are on your own with your wonky UK weights and measures...

Casper, what is the ethanol content of the fuel sold in your part of the world? When I was in Europe a few years ago 15%(possibly greater) was available as a cheaper fuel but the mileage (OK Kilometerage?) did not seem to offset the cost difference. Octane ratings significantly lower that recommended can also cause consumption issues. This is harder to diagnose as different methods are used around the world. Here in the US we use the (ROM+MON)x2 method but this varies around the world.

This may help you in identifying what you have for comparison. https://en.wikipedia.org/wiki/Octane_rating


Slow morning.

[great white]

For the math impaired here in the USA

1 liter = 0.2641721 Gallon
1 gallon = 3.785412

1 KM = 0.6213712 mile
1 mile = 1.609344

1 mpg = 0.425143707 Kilometers per liter
1 KPL = 2.35214583 Miles per gallon

For reference:
Roverfj1200's 16.5-17 KPL = 38.8 - 40  mpg
Caspers 14 KPL = 32.9 mpg


You UK folks are on your own with your wonky UK weights and measures...

Slow morning.

Easy peasy:

1 liter is one liter

1 Imp gal is 1.2 USG

1 imp gallon is 4.55 L

Different units of measure is why most of the world is converted to metric measurements

In Canada, when we convert from metric to gallon, most people do it to USG vice Imp. But it varies from person to person. I'm the
"in between" generation so I'm half metric, half imperial. Some things I understand better in standard, some things in metric.

My daughter references to all metric.....

[FJ1100mjk]

and set the float levels a few millimetres lower than stock to lean it up a bit..

Please explain how this leans fuel consumption. Not sure myself, because I never heard of this method.

My thoughts are that the fuel flow wil be governed by what amount flows through the various jets, and the flow of air through the intake tracts, that are governed by the position of the throttle and speed of the engine.

[balky1]

On my 85 FJ consumption is around 6.5 L/100 km with speeds to about 150 kph. On 200+ kph consumption rises to about 7.5 L/100 km.

I often pour in 100 octane fuel, but when I can't (and I think I probably won't anymore because I haven't noticed any difference in performance nor consumption)  I pour in 95 octane.

I must say that I've read somewhere that octane measure is not the same in Europe and USA. Be advised. I don't know the relationship.

[FJmonkey]

My '89 has UNI dual pods and an RPM exhaust and the carbs seem to be jetted properly for it. After checking my odometer with my GPS I found it to be about 5% over. So using the trip meter my last 6 fill ups resulted in an average MPG of 41.6, the best 46 and worst at 36.7. When corrected to actual (5% lower) I get 39.5 AVG, best 43.7, worst 34.9.

To convert MPG to KPL use this: 1 Mile per gallon = 0.425143707 kilometers per liter

Converted to KPL my AVG is 16.79, best 18.58, worst 14.83

[Arnie]

My 88 1200 gets 16.5km per litre and close to 17km per Litre 2 up.

Did anyone else notice that he changes his riding style when 2 up?  :-)
Are you being considerate and cautious, OR do you just not like getting punched in the kidneys?

Arnie

BTW  I get about 17km/L in cruise mode on my 1200.  Usually about 350kms safely to a tankful.

[movenon]

Not very extensive data but the last 3 tank fulls.

45 mpg (using the FJ odometer)
49.2 mpg        "
49.5 mpg using Garman GPS 270 mile run  

1990 FJ 1200  #155 Air Pilot Jet, #42.5 Fuel Pilot Jet, 117.5 mains, adjustable needle set in mid position, #1 and # 3 fuel/air screws at 2 3/4 turns out, #2 and #3 at 2 1/2 turns out. floats at 22.3mm, 4 degree advance. Plug readings look good across the cylinders. Elevation 3000 feet +-. UniPod filters, Cobra mufflers, fresh plugs, coil relay mod.

The next adjustment is to set the needle 1 clip richer.  I am not an aggressive rider but do like to run/cruse at 4-5 RPM most of the time.  Mark (FJmonkey) has a lot more extensive data. I am still adjusting and tweeking.
George

[roverfj1200]

and set the float levels a few millimetres lower than stock to lean it up a bit..

Please explain how this leans fuel consumption. Not sure myself, because I never heard of this method.

My thoughts are that the fuel flow wil be governed by what amount flows through the various jets, and the flow of air through the intake tracts, that are governed by the position of the throttle and speed of the engine.

The purpose of the float system is the maintenance of the fuel at a pre­determined level in the carburetor at all times, under any operating conditions. Since the float system controls the flow of gasoline into all the other circuits of the carburetor, its setting and operation must be correct. If the float is set too low, the engine will starve for fuel at higher speeds. On the other hand, should the float be set too high, too much fuel will flow through the carburetor circuits and the engine will load or a mileage complaint will be the result. The float system can only operate properly, if there is little or no wear in the operating parts such as needle valve and seat, float pin or float lever holes.

[FJ_Hooligan]

Richard,
While your answer sounds logical, it fails to take into account the nature of the CV carb which maintains a constant vacuum level in the throat. 

A higher fuel level will be more easily pulled into the intake potentially making the mixture richer for a given needle setting.  Lower fuel level will be leaner.  Changing the fuel level would be like a fine adjustment to the needle position.  More or less fuel is available all the time.

[roverfj1200]

Richard,
While your answer sounds logical, it fails to take into account the nature of the CV carb which maintains a constant vacuum level in the throat. 

A higher fuel level will be more easily pulled into the intake potentially making the mixture richer for a given needle setting.  Lower fuel level will be leaner.  Changing the fuel level would be like a fine adjustment to the needle position.  More or less fuel is available all the time.

You seem to have answered it right there. Lowering the float level a bit also helps with the FJ "fuel leaking from carb lines" problem which it would seem every bike has now and then.