UK, 2007, FJR1300 mpg - point of note

[nick]

Being as it was a not bad afternoon here in the South of the UK, I took the bike out to give it a bit of exercise and noticed I had left it on instantaneous mpg - anyway, I left it there as I have been meaning to see what the consumption is at various steady speeds... I was shocked to note the following..... (Gallons are UK gallons)

At engine speeds up to 4900 rpm (indicated) the mpg steadily dropped - so far so good.... this equates to around a true 90 mph in top, with around mid forties mpg at around just under 4900 rpm... However, go another 100 rpm up to 5000 rpm, and the mpg drops very dramatically to around low to mid thirties. I am so surprised with this that I need to check again before I am sure, but if it is the case, touring will have to be done at around 4800 rpm, which in Spain with nothing in sight in any direction is a bit limiting ! However, if it makes this sort of difference, it would pay well on tank range to stay just below rather than just above the "line"... Also as I said elsewhere, I am sure that ambient temp makes a noticeable difference to mpg as well.

I can't believe a surge or a hesitation is not apparent - however it does explain why some of the figures on the Power Commander maps suddenly seem to have big numbers in the cells at around 5000 rpm, presumably smoothing out the step. I assume it is where Yamaha have decided - "thats enough of the economy bit, now for the power ! "

I will do the plugs and TBS shortly and check again - still undecided whether to go for a Power Commander, although it would seem that it may significantly help economy if the lean burn was extended / continued from 4900 up to say 6000 rpm on fast cruises....

Anyone else found similar ?

Cheers,

Nick

 

[Jagermeister]

Someone said "there are no stupid questions," but this one will push the envelope:

Does the FJR have Variable Valve Timing (I think not)? If it does, that would explain a sudden drop in fuel economy at a certain rpm.

 

[nick]

Someone said "there are no stupid questions," but this one will push the envelope:
Does the FJR have Variable Valve Timing (I think not)? If it does, that would explain a sudden drop in fuel economy at a certain rpm.

I, for one, am pretty sure to certain that it does not.... - I am thinking that the effect I am noticing is purely moving up the mapping of the fuel injection system and there's a big step at the point I mentioned from "economical" to "power orientated"

Nick

 

[Bungie]

Someone said "there are no stupid questions," but this one will push the envelope:
Does the FJR have Variable Valve Timing (I think not)? If it does, that would explain a sudden drop in fuel economy at a certain rpm.

I, for one, am pretty sure to certain that it does not.... - I am thinking that the effect I am noticing is purely moving up the mapping of the fuel injection system and there's a big step at the point I mentioned from "economical" to "power orientated"

Nick

Most modern bikes are lean down low in the rpm range for economy/emissions purposes but fatten up nicely in upper midrange to top end. I know my Meanstreak feels 'flat' down low but runs like a ***** up from 4000 to redline. Yet it'll consistently nail down 53+ mpg in normal (sane) mixed riding.