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Bonneville SE Fuel Consumption Running in

8K views 24 replies 15 participants last post by  Shorebird 10 
#1 ·
Hello All
just running my Bonneville SE in and suprised the consumption is high at 34 mpg, hopefully this will improve alot once running is complete. Also the fuel pump screeches as opposed to whirring.
normal? Will get the dealer to check things of course.

impressed so far with the bike and yes the warning lights are rather dim! Solution to fit led bulbs, if so what ones?

Cheers
Steve aka Stevo
BSE
GB
 
#2 ·
mine went up further into break in on my thruxton...close to 38 to 40 I think but I am not a very "conservative" rider...it is more than my '89 Blazer so I am happy...

my fuel pump screeches some if it is cold outside, otherwise...it whirrs away....
 
#5 · (Edited)
just running my Bonneville SE in and suprised the consumption is high at 34 mpg, hopefully this will improve alot once running is complete. Also the fuel pump screeches as opposed to whirring.
normal? Will get the dealer to check things of course.

impressed so far with the bike and yes the warning lights are rather dim! Solution to fit led bulbs, if so what ones?
During running-in I was getting around 45 mpg (UK gallons, 37.5 US gallons), there's something wrong there. Are there any fuel leaks?, I ask because the only time the fuel pump screeches rather than purrs, is when I remove the tank and the hose loses some fuel. On re-assembly the pump has to prime the system and get rid of the air inside the empty hose, making that noise.

It sounds as if your system is either losing some fuel or gaining some air.

LED Idiot lights from newbonneville.com are really good and I have fitted them to great effect.
 
#6 ·
During running-in I was getting around 45 mpg (UK gallons), there's something wrong there. Are there any fuel leaks?, I ask because the only time the fuel pump screeches rather than purrs, is when I remove the tank and the hose loses some fuel. On re-assembly the pump has to prime the system and get rid of the air inside the empty hose, making that noise.

It sounds as if your system is either losing some fuel or gaining some air.

Thanks everyone :)

will sort this out with the dealer pronto! then look into getting brighter warning lights too. other than that very happy.

Steve.
 
#10 · (Edited)
book just gives general advice on running in etc.
is not over 50 mph acceptable? just want to be kind to the ol gel.
Running-in an engine properly makes all the difference, you can rev it high, but never with full throttle or for prolonged periods, also never lug them up hills, get into a lower gear and keep revs up using low throttle.

The ideal running in regime - You need the revs to free things up and make sure there are no high spots but not loading the engine by giving it too much throttle.

It was always suggested to me that the actual revs are not a problem within reason as long as the load on the engine is not high , so running along on half throttle down hill at near max speed is better than lugging up a hill in top "keeping the revs down" !

Heat build up is the enemy when running in. If you do a long run while running-in, stop once in a while to let things cool down.

There's a school of thought that recommends full throttle occasionally for short bursts during the initial period of running-in. This is to ensure that combustion gasses get well behind the piston rings and force them onto the cylinder. This removes the last of the machining roughness and beds the cylinder and ring in properly.
Failure to do this means that the cylinder walls will glaze over and cylinder pressures and therefore compression will be lost in the future. No real damage, but lower performance.

You can read about the "thrash it from the beginning" philosophy here:

http://www.mototuneusa.com/break_in_secrets.htm
 
#11 ·
I was getting 45mpg consistenly whilst running in. It's a little better now, but not a lot.
This engine should be capable of better mpg, especially with efi. My 98 triple gives me 50-55 mpg.

I put it down to pumping losses, with the air intake and exhaust being so restricted on new bikes.
 
#12 ·
I put it down to pumping losses, with the air intake and exhaust being so restricted on new bikes.
I've recently read an article that claimed that better fuel consumption could be obtained by opening up the throttle a bit more, rather than trundling along on a nearly closed butterfly valve.
This was down to the pumping losses you mention. It came as a complete surprise to me, never having given them a second thought.

This engine also drags around a lot of gear: twin oil pumps, twin balance shafts, twin cams, eight valves and their springs, etc.
 
#15 ·
Everyone keeps on about the bike being heavy but I can handle her better than my old cbf, It must be the low centre of gravity.

MP gallon today doing 90ish on the motorway, pants, had to keep filling her up every 100ish miles..didn't let me down though and so planted, well chuffed today.
 
#17 ·
41 mpg on my '09 SE today after some very spirited riding. Closer to 50 mpg when cruising. Bike has 2500 miles on it.

Could regional fuel formulation play a part in variable results? I noticed today that the gas at the last stop had a decal reading "10% ethanol." That can't be good for energy density.
 
#18 ·
Best mileage for my Bonneville SE is 45 mpg and that was during break in with constant short shifting. I'm now at 1500 miles with Triumph Accessory silencers and dealer remap. My gas mileage is now 39-41 mpg. I've tried all types of shifting modes and it doesn't seem to matter as far as mpg is concerned. Anybody discover if gas grade has any effect??? I think someone here said that high octane gas is wasted on low compression engines....
 
#19 ·
I think someone here said that high octane gas is wasted on low compression engines....
On an EFI engine fitted with detonation or knock sensors, higher octane premium gas gives a significant boost in power as the system "learns" that it can advance the ignition to suit the premium fuel.

The Bonnies don't have that refinement, so it would make no significant difference unless we re-map the ignition to provide extra advance.
 
#21 ·
My last trip (and first real 'long' trip out of town) had me crossing 2000mi on the odo at the end of the day and making 50mpg according to my calculation at the fuel stop around 1940mi. I was cruising between 50mph and 70mph.

I'm either impressed with the fuel mileage or unimpressed with the odometer being as inaccurate as the speedometer. I need to set up a known distance test trip for the odo.
 
#22 ·
Sorry to dig up an old thread.

2010 Bonneville SE, 5100km on the clock (about 3187 miles).

Getting normally around 16km/l (or around 38mpg), is that normally?

My old carb'd Scrambler used to get around 17/18km/l if I recall correctly.

Now bare in mind this is mainly subburb/city/commuting/little bit of motorway riding.

Not endless highway stuff.

Cheers,

-Indy
 
#24 ·
I bought my 2010 T100 she had 2200mls on the clock, about 2 months ago.

Now she must have about 4500mls and in that time my average speed has increased from about 50mph to about 65mph and the fuel consumption has increased from, on average, 50 mile per UK gallon, to on average 56mpg.

The bike is revving better, carries both of us fatties easily and is the best bike I've ever had - and I had some good'uns!


Dave
 
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