RPM's at 75-80 mph?
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ionbeam
2 FUN
Speed to gear chart for Gen I FJRs.
Speed to gear chart for Gen II FJRs.
From the Micapeak FJR1300 web site you can open a Dynamic Spreadsheet that will let you calculate all types of speed/gear/ratio/tire size combinations.
All these charts are straight, by the numbers calculations, the actual speed you read on your speedo will differ because the speedo readings are not perfectly accurate for a verity of reasons. Trust your tach, it will be pretty close.
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unclekunkle
Active member
Speed to gear chart for Gen I FJRs.
Speed to gear chart for Gen II FJRs.
Looking at the two charts here, the Gen II bikes are able to "exceed" 60 M.P.H. while still in first gear, compared with Gen I bikes that have to be shifted into second gear in order to reach 60 M.P.H. So does it stand true that an '06/'07 "might beat" a Gen I bike to 60 ? (which is specified to accomplish in 2.8 seconds)
Speed to gear chart for Gen II FJRs.
Looking at the two charts here, the Gen II bikes are able to "exceed" 60 M.P.H. while still in first gear, compared with Gen I bikes that have to be shifted into second gear in order to reach 60 M.P.H. So does it stand true that an '06/'07 "might beat" a Gen I bike to 60 ? (which is specified to accomplish in 2.8 seconds)
SkooterG
Purveyor of Crooked Facts
Nope. For a strictly 0-60 timed measurement all that needs to be done is to rev the Gen I FJRs to a little over the 9000 rpm redline. Voila! Once again Gen I has spanked those portly Gen II butts.
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SkooterG
Purveyor of Crooked Facts
Gonna disagree with that. I don't profess to know what the "why", but.............
There is some other kind of error at the higher speeds. Tire slippage, tach error, speedo error I don't know. When doing max velocity something isn't making sense in relation to the chart or even the FJR's own speedo/tach relationship.
For example, if just a few days ago some fictitious FJR rider had done a top speed run, at terminal velocity his GPS read 153mph (which he assumes is pretty accurate), his speedo read 159, or perhaps 160, and the tach read 9200-9300 rpm. So the tach does not match the speed in the chart. However, interestingly enough, the tach and speed correlate closely to the graph, even though they are both in error.
Now for the interesting part. Given the numbers above, if one were to half the rpm to 4600 rpm, then the speedo should read aproximately 79mph, and the GPS 76mph, right? Not so. That bad FJR rider above would have to go check it again, but past experiences showed that approximately 4600 rpm the speedo was reading 82 mph or so, and the GPS 80mph or so. So something fish is going on there. I ......errrr.....I mean, HE thought the tach would be accurate too, but that is not the case. At least as speed approaches terminal velocity.
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ionbeam
2 FUN
0-60 times: The Gen II has a numerically higher gear ratio that doesn't permit acceleration to be as quick as the Gen I due to the Gen I's lower gear ratio (with torque/hp of the engine remaining the same between Gen I and Gen II). (FWIW) Motorcycle magazines test results show the Gen II to be slower, not major, but in line with the steeper gear ratio. I have in hand some time slips from full 1/4 mile runs at the dragway, anyone with a Gen II have a slip for comparison? All the Gen I time slips that I have seen are pretty close with most of the e.t. diffrences showing up in the 60' times which is launch management. Reaction time does not factor into e.t.
When I say the tach is pretty close I had in mind something on the order of +/- 3% which is 30 rpm at idle and a few hundred RPM at red line. The engine speed is picked up off the engine crank and needs to be accurate enough to manage the fuel injection so the pickup error has to be pretty small. The tachometer itself is simply an indicator, and it can be wrong because it is servo driven (at least in the Gen I, dunno about the Gen II). The only time the tach needs to be close is when it is indicating idle rpm. It would be nice if the tach was close again at >9k rpm. Should you venture there, it would give you some warning about when the first and second stage of the rev limiter kicks in. IMO, for street use the tach is accurate enough.
In the Gen Is, the speedometer pickup is the VSS signal coming from a sensor in the engine. Speedos are basically trend indicators, never to be taken too seriously.
Note that the FSM always tells you to use an inductive pickup tachometer to accurately measure engine speed.
When I say the tach is pretty close I had in mind something on the order of +/- 3% which is 30 rpm at idle and a few hundred RPM at red line. The engine speed is picked up off the engine crank and needs to be accurate enough to manage the fuel injection so the pickup error has to be pretty small. The tachometer itself is simply an indicator, and it can be wrong because it is servo driven (at least in the Gen I, dunno about the Gen II). The only time the tach needs to be close is when it is indicating idle rpm. It would be nice if the tach was close again at >9k rpm. Should you venture there, it would give you some warning about when the first and second stage of the rev limiter kicks in. IMO, for street use the tach is accurate enough.
In the Gen Is, the speedometer pickup is the VSS signal coming from a sensor in the engine. Speedos are basically trend indicators, never to be taken too seriously.
:blink:
Note that the FSM always tells you to use an inductive pickup tachometer to accurately measure engine speed.
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mcatrophy
Privileged to ride a 2018 FJR1300AS
The speedo and tacho are both electromagnetic in operation, that is they work by passing current through a coil and use the magnetism to pull them round in a magnetic field.
To make them linear is difficult (read costly), and since they only need to have a limited accuracy (depending on your local vehicle regulations), you can't expect them to be overly linear or accurate. I always treat vehicle instruments as "indicators" not "meters".
A digital readout of engine or vehicle speed is more likely to be accurate (or at least linear), but I personally prefer the analogue even with its inherent inaccuracy.
In some respects, the old "mechanical" units were better ...
ionbeam
2 FUN
What mcatrophy relates to us about magnetic based instrumentation is correct.
In the case of the old Gen I FJRs the instrumentation is driven by a serial digital signal that provides the inputs for the servo motors in the tach and speedo gauges.
mcatrophy has one of them there newfangled '06s, can't speak to what they have for instrumentation.
In the case of the old Gen I FJRs the instrumentation is driven by a serial digital signal that provides the inputs for the servo motors in the tach and speedo gauges.
mcatrophy has one of them there newfangled '06s, can't speak to what they have for instrumentation.
mcatrophy
Privileged to ride a 2018 FJR1300AS
Are you saying Yamaha use servomotors in their instruments? I'd be (1) pleasently amazed, (2) wrong in my diagnosis. A servo driven meter would be expensive (good for Yamaha), and potentially very accurate.
The only wiring diagram I have is for the earlier FJR and it shows little more than a block for the "meter assembly".
Something's not quite right about those graphs.
There's not that big a difference between the two FJR versions.
For a given road speed:
'05 RPM = '06 RPM X 1.0278
Or, for a given RPM:
'06 MPH = '05 MPH X 1.0278
There's not that big a difference between the two FJR versions.
For a given road speed:
'05 RPM = '06 RPM X 1.0278
Or, for a given RPM:
'06 MPH = '05 MPH X 1.0278
ionbeam
2 FUN
There is a single serial data line between the ECU and the Meter. The serial line has to go through a MUX Decoder (signal demultiplexer) to break out the various signals and values. The owners manual refers to the "Electric Speedometer" and "Electric Tachometer". The Owners Manual says:
If you look at the FSM (Factory Service Manual) you should see in a couple of places in the manual that the meter assembly receives a single serial data line from the ECU, the rest of the indicators and functions receive their signals from switches.
I have a couple of burned out lamps in my Meter Assembly :angry2: so I will have it apart once the temperatures get above 10°F and then there won't be any secrets
There is similar text about the speedometer.
If you look at the FSM (Factory Service Manual) you should see in a couple of places in the manual that the meter assembly receives a single serial data line from the ECU, the rest of the indicators and functions receive their signals from switches.
I have a couple of burned out lamps in my Meter Assembly :angry2: so I will have it apart once the temperatures get above 10°F and then there won't be any secrets
ionbeam
2 FUN
The Gen II does have different gearing. The graphs were generated straight from Yamaha gear specs. I have been know to make mistakes,
check the gear ratios and do the math. I entered the formulas and gear data into Excel so the results should be as accurate as my formulas.The tachometer and speedometer are driven by stepper motors.
The I graph shows approximately 70 mph for 4K rpm in 5th gear.
The II graph shows approximately 76 mph for 4K rpm in 5th gear.
That's too big a jump in mph.
70 X 1.0278 = 71.95 mph
That's quite a bit less than 76 mph.
The II graph shows approximately 76 mph for 4K rpm in 5th gear.
That's too big a jump in mph.
70 X 1.0278 = 71.95 mph
That's quite a bit less than 76 mph.
mcatrophy
Privileged to ride a 2018 FJR1300AS
Stepper motor = Good. Can be as accurate as Yamaha wants it to be, but my experience also is that it's about 3 mph fast at 70 (going by my GPS), and seems to be about 5 mph fast at 90. Difficult to say whether it's linear, I find it hard to look at speedo, GPS and the road for speed cameras and hold the speed constant.
Ratios: I did my own (so totally independent) Excel spreadsheet, the results can be seen here (sorry it's not very profesional, I only did it for my own edification). This was done before I got my FJR to compare with my Trophy's mph/1000 rpm.
Mine shows about 75.4 mph for 4000 in 5th.
Ratios: I did my own (so totally independent) Excel spreadsheet, the results can be seen here (sorry it's not very profesional, I only did it for my own edification). This was done before I got my FJR to compare with my Trophy's mph/1000 rpm.
Mine shows about 75.4 mph for 4000 in 5th.
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ionbeam
2 FUN
I just did the ratios again from scratch and my numbers are pretty close to mcatrophy's. In the chart I reference earlier in this thread I had Excel do some rounding of values so that I show 76 when mcatrophy shows 75.4 If I'm wrong, at least I'm consistent :lol:
charismaticmegafauna
Well-known member
Isn't there still a discrepancy?
Did Yamaha change more than the small amount of gearing change in the intermediate drive? IIRC, they said it was for 'noise issues'?
I tend to agree with 'Constant Mesh' from what I've read -- but, haven't ridden a Gen II.
71.95 or 75.4? :huh: :blink:
I wonder what terminal-terminal velocity would be? Maybe the "bad FJR" rider and another "accomplice FJR owner" should get together and charter a plane with a back ramp. As "bad rider" rides "Flipper" out the back of the plane what kinds of speeds, tachometer readings, and amount of pushed out poop do you think would be generated?
My guess is somewhere around 250 mph, rev limiter, and a whole ****-load respecitively.
Of course, this test could only be done once, but it would be an interesting data point.
Or maybe we could the Mythbusters to weigh in on it
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