As the previous thread with similar title went pair-shaped sometime in 2013 due to trolling, I decided to start a new thread on the topic which has been troubling me recently. Some of the content below I also posted in the AF-XIED thread, but given the question of fuel consumption is more general I thought that it justified a separate post. For the past month or so I have been monitoring fuel consumption and it is consistently around 44MPG or in metric about 5.4l/100km. The bike has the podmod and is running an AF-XIED at setting 9. The front sprocket has been changed to a 15t. My riding consists of mostly 60km/hr commuting. I guess my riding style is fairly 'spirited', generally accelerating pretty hard to get ahead of traffic, etc, but nothing like flat-out all the time. Compared to the figures I have seen under the previous 'fuel consumption' thread, mine seem to be way over the average - perhaps 20% over average. However, I note that someone on ADV recently posted an adventure bike comparison article which included a TR. The average fuel consumption that the reviewers recorded for the TR was almost exactly the same as mine. Naturally, I understand that the AF-XIED will add a predictable margin of fuel. Nor do I mind some increase in fuel consumption. But it does seem excessively high. Do these consumption figures seem unreasonable given all the factors mentioned above? Does anyone else have similar consumption figures?
I recorded my fuel consumption on the phone using an app. And have from first tank till now. I've got about 25000ks on the clock. If I follow some one or ride in a group my bike does 3.8l to 4.3l to hundred. If I'm comuting then 4.3l to 4.6l. If I'm out for fun then up to 5.2l. With the app I use I can tell when I need to replace the spark plugs as the consumption starts to climb. And now I'm due for my fourth set of plugs. Greg
DeLewis, on a 1278 km trip last August that included some spirited back road riding , fire roads and even a little freeway time my Terra with 15 front sprocket but 17 in rear wheel (ABS), 3D printed air box mod, and AF-XIED set on 6 then 7; I averaged 4.96 ltr per 100 kms with a SD of 0.32. Max consumption was 5.34 and min was 4.55. I trust this helps. M
I have found 2 factors that seem to effect my fuel milage. One is distance driven between start/stops or number of starts per tank. On my daily, all rural roads commute, where I start the bike 16 times on a tank I get around 45 mpgs. However on weekend rides where I ride pretty much the same way but run a lot further with maybe 2-4 starts per tank that number climbs to around 49 mpgs. The other factor is altitude. I live at sea level, when I am in the mountains I see up to 59 mpgs and never see less than 52.
Thanks for the feedback. It seems my figures are perhaps not too extreme. This morning I adjusted the AF-XIED down to 7 and rode more conservatively and managed about 4.8l/100km - quite a dramatic reduction from 5.4l! But the bike performance was also a lot softer than I like so I guess that's the trade off!
I'm averaging 3.7 l/100 km for my daily commute to work which consists of mix of suburban and freeway. Recently did Pod mod and since then 3.8 l/100 km. Stock sprockets.
I don't know if it is relevant in your case but the gear you're riding in makes a great difference to fuel economy. The following chart is typical of many Spark-Ignition gasoline engines. I could not find a TR650 BSFC chart so I found one to illustrate the points. There are some observations that can be made since most charts I found (even Diesel) look a lot like this one. As an example, say you're riding at a speed that requires 20% engine power. If you're in a gear that leads to 2000 RPM the BSFC is 0.42-0.45 lbs/HP/Hr. Compare that to a gear that leads to 3000 rpm, which uses 0.55 lbs/HP/Hr. The higher RPM, same speed needs about 25% more fuel. The reason is that the engine is a LOT more efficient with the throttle open wider. If you run that same power at 4500 RPM the BSFC jumps to 1.00, which is more than twice as much fuel! (BSFC stands for Brake Specific Fuel Consumption) Comparing mileage takes a pretty detailed control of gears, speeds and course ridden. If you add 6% to Closed Loop fueling you should see a reduction in mileage at high speeds where you're already in top gear. At lower speeds if you can run one higher gear (say 5th vs 4th), there may be no reduction in gas mileage.
