Speedometer Readings / Max speed vs Actual max speed

Hey guys,

I hope this is approprate for this section of the forum. I tried searching for the answer and couldn't find the information I'm looking for.

I am a proud new owner of an 83 XJ750 Maxim, I had a question about the spedo. It shows the max red-line is 85 mph, but the spec on these bikes say the top speed is 128mph.. How come they put a limit on the speedo so it doesn't read what the bike can do?

Are there any replacements that have an accurate reading?

 

the only red line you have to worry about is the one on the tach around 10 k for you.
the red on the speedo is just telling you you may want to slow down you are moving down the road kind of quickly.
speedo limit is because of the 55 mph speed limit in place at the time .
you can change your speedo to a higher speed one but at that point do you really need to know how fast you are going.
my eyes would be on the road not the speedometer.
2 miles per minute is just a blurr

new to riding or just classic antique bikes?

 

Us Canucks had a good giggle back in the day when we saw the 85 mph speedos on US models
My take on that was how fast can we max out the speedo and do the math on how fast we really were traveling!
Rpm at 50x2 is 100 + at 10k
But that's why we cover the speedo for track use. I don't care what speedo might tell me I just need to know what gear at each corner

 

https://en.wikipedia.org/wiki/National_Maximum_Speed_Law

The accuracy of your speedometer isn't related to the range of speed that it measures. The easiest way to see how large of a speeding ticket you'll be getting is to mount a GPS unit to your bike.

 

That makes sense. Thanks for the reply guys. I was just curious because on my previous bike, the spedo showed the bike's relative stock top-speed. I was just curious why this particular one was cut off at 85.

Neither! - I have been riding since I was a little squirt, started on mini bikes, dirt bikes, and then eventually motorcycles, I've been riding motorcycles for over 15 years. I am coming from a Suzuki GS650, that was partially what sparked my curiosity about the speedometer reading because the GS650's cluster showed 125 for it's top speed. I'm not really too concerned about going that fast, I just wondered why Yamaha decided to cut the display off at that mark.

I have always loved yamaha's, the XS650 was my first true Yamaha love, sadly I didn't get to keep it very long, life happened and you know how it goes. I just got the xj750 from a buddy who gave me a killer deal on it, so I had to jump on it. Especially because it's a Yamaha!

Thank you all for the replies I appreciate it!

- Barry

 

It wasn't Yamaha's decision. Pick any U.S. sold vehicle of the era and it will have an 85mph speedometer.

 

The Ronald Reagan era. Better fuel economy. Fewer highway deaths.

On the bright side, he is credited with the downfall of the Berlin wall.

 

The theory was an 85 mph speedometer would keep people from seeing how fast it will go. My 1980 Honda Accord had one too. Theory didn't work

 

Tape your phone to your tacko and use the digihub app to compare/record the actual speed to the speedo on your bike. Do this BEFORE you get to pay a $215 ticket for doing 73 in a 55.

Gary H.

 

thats why the world is in the sh** hole it is today, if US could not keep someone in line the USSR could. bomb them and you whole town would dissapear.

 

15 years that would be considered new to a few of us, considering the bike your riding is 30 years old

 

There is a radar speed notice coming into my town on a county road. The speed limit in the area is only 25 mph, but I speed check my speedometer against it. Up to about 35 mph my speedometer is spot on, after that I can't vouch. Don't want to get caught doing more than 10 mph over the speed limit in that area!

 

If it would are you feel better, put a 135mph speedo on it.........