CB650F Fuel economy.

[ADIOS600]

This is a follow on from my gearing post, RoadHog asked about fuel economy after fitting my 44t sprocket. 100 mile ride revs between 6,500 and 9,500 approximately, up and down the box trying to get rid of a fazer in my mirrors, 45 mpg. Next day 105 mile ride no more than 5,750 revs 75mpg. What do you guys get.

 

[Kingsleh]

I've been throttle happy lately since I've been able to legally ride mine (alone) since last friday, but on a highway ride with shitty road conditions and either wind or horrible drivers all around I've been able to get about 63mpg. Bike is completely stock mechanically.

 

[Rogue]

I'm averaging around 55 MPG (UK/imperial so ~ 46 MPG US I think) on stock 2017 CBR650F but that is mainly high speed motorway miles

 

[Road Hog]

Adios600,75 mpg with 44t rear sprocket? Really, I am lucky to get that on my cbr250r,and did you put a speedo healer on?
Your odometer will be putting on more miles if you don't.One more thing ,at 9500rpm do you remember what speed you were going?

 

[ADIOS600]

Well Road Hog no speedo healer that's one reason for the two teeth instead of one off the front, it's under 5% difference and I calculated for that in my figures. It's doing about the same as the other guys. Plus I have no cat and I think it runs much better now. Don't know what speed it was doing at high revs.

 

[Road Hog]

Adios600, Well 5% not much difference so i would not put a speedo healer on either. Did you put a 525 chain & sprocket system or
a 520 system? Please answer quickly as the rats are killing us over here?

 

[ADIOS600]

Adios600, Well 5% not much difference so i would not put a speedo healer on either. Did you put a 525 chain & sprocket system or
a 520 system? Please answer quickly as the rats are killing us over here?

View attachment 1684

I should call you Road Kill. Just put a sprocket on the back that's it. I must have done about 500 miles with it on. Once it gets to 5,500 revs which is about 72 in top it pulls like a train.

 

[RHOSH]

Road Hog ,what do you mean by you will put on more KLM on speed once you have done rear sprocket ?

What effect does the speed healer have on the bike ?

I've changed mine heaps more power down low but have notice doing 100 KLM has gone from 4000- to 5000 RPM

 

[Road Hog]

By changing your rear sprocket two up or your front sprocket one down[which is the same as 3 up in the
rear sprocket] it not only changes your speedo but your odometer as well. Also do you gain more power???
Your speedo healer adjust's to stock setting.
https://www.superstreetbike.com/bigger-rear-sprocket-makes-more-horsepower-mythbusters

 

[ADIOS600]

Road Hog ,what do you mean by you will put on more KLM on speed once you have done rear sprocket ?

What effect does the speed healer have on the bike ?

I've changed mine heaps more power down low but have notice doing 100 KLM has gone from 4000- to 5000 RPM

You must have made a big change in gearing.?

 

[Dodgy]

I have fitted a 38 tooth rear sprocket, better on top end ,not so revy but it's knocked my Speedo out , by 5mph any idears to to recorrect the speedo

 

[miweber929]

Speedohealer

 

[Rocket Crotch]

This is a follow on from my gearing post, RoadHog asked about fuel economy after fitting my 44t sprocket. 100 mile ride revs between 6,500 and 9,500 approximately, up and down the box trying to get rid of a fazer in my mirrors, 45 mpg. Next day 105 mile ride no more than 5,750 revs 75mpg. What do you guys get.

I don't think you're actually getting 75 MPG. The bike uses the odometer to calculate MPG based on what the ECU is spraying through the injectors...and if you change the rear sprocket +2T, you need a speedo healer to correct not only the speedometer, but the odometer as well. Right now you are counting more miles than you're actually traveling, so it appears your MPG is higher when it's actually your odo giving you a false reading of more distance than actual. Realistically, you're probably around 50-55 MPG. I can score 52-53 MPG riding on highway, prior to my windscreen it was 47-48 MPG.

 

[ADIOS600]

I don't think you're actually getting 75 MPG. The bike uses the odometer to calculate MPG based on what the ECU is spraying through the injectors...and if you change the rear sprocket +2T, you need a speedo healer to correct not only the speedometer, but the odometer as well. Right now you are counting more miles than you're actually traveling, so it appears your MPG is higher when it's actually your odo giving you a false reading of more distance than actual. Realistically, you're probably around 50-55 MPG. I can score 52-53 MPG riding on highway, prior to my windscreen it was 47-48 MPG.

I took the 4•6% difference into the calculations, have you done a fuel economy run ? 😇

 

[Rocket Crotch]

A @ADIOS600 No, but I keep my tires at stock pressures and have not changed my gear ratios. The average MPG on the display I go by matches dividing the trip mileage by fuel amount on the gas pump. I haven't come close to 75 MPG on straight highway riding.