Rpm To Mph Conversion?

[kerhrhr]

Does anyone have the conversion formula for calculating RPM's, in any gear, to MPH? I went out the other night for a ride, and some guy on another bike pulled up next to me, acting kinda squirrelly, so I gave him a run. He disappeared pretty quickly, but I didnt' catch what my speed was. I was at 8300 RPM's in 5th gear. Thanks......

Aaron

 

[speedjunkie]

https://www.fjrowners.ws/fjro4/usa.html

In the RH upper corner under Tech info, there's a link to FJR speed in gears. I'd post a pic, but can't figure out how. Sorry.

Mike

 

[kerhrhr]

Thanks Mike,

Was that your chart? If its right, then I was doing about 145mph! Hot damn, that's fast! The fastest I've ever been on a bike, anyways. Awesome! Thanks again. I appreciate it.

Aaron

 

[FJRocket]

 

[04FJR4ME]

I have a question about RPM and Speed charts,

Just wondering what other factors can make the numbers change, headwind, slipping clutch, weight of rider and gear etc, just because the RPM is high does it mean the speed must be exactally right in relation to the RPM?

 

[Rogue]

I have a question about RPM and Speed charts,Just wondering what other factors can make the numbers change, headwind, slipping clutch, weight of rider and gear etc, just because the RPM is high does it mean the speed must be exactally right in relation to the RPM?

Wheel diameter: Is it worn down? Is it slightly larger than stock?

Wheel spin: Even if your not leaving a black mark the wheel can be spinning slightly.

Cluch slippage: That should not be a factor.

Those are the top 3 things off the top of my head.

 

[ohiofjr]

Go 4150 rpm and look at speedo then double the mph.

 

[GalaxyBlue]

Has anyone else hit the rev limiter? Mine bounces off it at 10k! I thought it was 9k

 

[04FJR4ME]

Has anyone else hit the rev limiter? Mine bounces off it at 10k! I thought it was 9k

I am not interested in seeing my motor in pieces or cause it to tick prematurely, thank you!

 

[dunhamg]

You think Yamaha would put a rev limiter that does you no good? Mine has been off the rev limiter more than a couple times. Still running great at 50,000 miles.

Grady A. Dunham

 

[Windjammer]

The rev limiter is a safety feature. Shifting at anything more than about 8500 rpm will actually slow you up in a dragrace, since you'd be shifting well after peak HP and torque.

That speed in gears chart should be looked at closely by those who favor taller gearing for the FJR. There's a good chance you wouldn't be able to pull 8300 RPM in a taller gear - there goes your top speed.

 

[FJRottie]

kerhrhr, The FJR will do around 155 MPH (give or take) (do it on a closed course).

 

[Windjammer]

kerhrhr, The FJR will do around 155 MPH (give or take) (do it on a closed course).

Theoretically, it could achieve 155 @9000 RPM. But only if there's enough power to overcome drag at that speed and propel you to redline in top gear - most bikes won't do this. Those with GPS have reported FJR top speeds of around 145 out in the wide open spaces, and this suggests that the FJR only reaches about 8250 RPM in top gear. Interesting that 8250 is also the approximate RPM at which HP and torque curves are dropping off from peak.

 

[dunhamg]

Actually, with my GPS I saw either 154 or 156, I can't be certain which. That was almost two years ago. It was a very cold morning, the temp was hovering about 18 degrees F so it was making very good power. This was with the bags on and a Ventura tailbag. Again, on a closed course

Grady A. Dunham

 

[C&C]

And Warchild's GPS, on his avatar, I believe, is showing 157.

(Too fast for me)

 

[FJRottie]

and I did 156 on a track, with the bags on. B)

 

[rogerfjrfaster]

I've had mine to 140 and 130 at 130 gps showed 126 so in upper triples its off by 4 mph.

rogerfjrfaster

 

[Windjammer]

Fair enough then, maybe the FJR does go that fast. I've never had a chance to top mine out, so my comments are based on what I've read on these forums where GPS users posted top speeds. Naturally, weather conditions and altitude will affect air density which will influence engine performance and the amount of wind drag.

WC also has a Blackbird, and the 157 mph on his avatar could have come from that bike. Besides, being the farkler that he is, his FJR motor is prolly not running a stock map, and mechanical parts may have been massaged a bit. Who knows?

So the real questions I have, for those who have topped a STOCK FJR out, is this: Did it reach redline in top gear or not? If it did reach redline, was it willing to pull past redline?

 

[kerhrhr]

Windjammer,

I have hit redline in top gear since I first posted about the RPM to MPH conversion. As I am still "breaking it in", I didn't dare push it past redline. I tested its "boundaries" and was satisfied that it would do what I needed it to do. My bike is still completely stock.

Aaron