Speedo inaccuracy

[srx70024]

I've been seeing these posts of guys reading 128 MPH or so on the speedo and only seeing 108 on the GPS. 20 MPH off ??? That's a lot to be off. I just find it hard to believe that Yamaha can't come up with a more accurate speedo.
The Rx-1's had this problem too, correct? Is there anything to do to make them a little more accurate ?

 

[BA APEX]

i had 15mph difference in a long smooth field. 118 speedo - 103 radar

 

[LazyBastard]

Mine (on 03) was off by 12 mph when running 121" track, less than 10 off with 144". If you don't grip, it will slip and give you a false high reading.

 

[srx70024]

So, these high mph readings could be lack of traction ? Get the power to the ground and it might be more accurate.....

 

[dburu2]

You can gind off 1 or 2 teeth on the pickup gear below the secondary clutch. Last year on the RX-1 I took off two teeth and the speedo when checked by Sheriff's deputy radar was 1 mph off, mine said 94,radar said 93 .another good thing is it keeps the milage lower by the same percentage. If you do the two teeth take 1 off on opposite sides.

 

[srx70024]

Just grind off a tooth so there is a bigger space where the old tooth was ?
Grind it right down to the radius of the pickup ?

Interesting. Anyone else try this with simliar results ?

Thanks for the info.

 

[SledderSteve]

Or......

You can add a recalibrator http://www.motorcycleradar.com/products,_pg5_6.htm
Sleds aren't the only vehicles with speedometer inaccuracy. :wink:

 

[dburu2]

Yes and it was a topic on the RX-1 forum last year so I believe their was a few who did it but most probably did 1 tooth .I did 2 to get the mph as close as poss. and I wanted to keep the milage down allso.

 

[leaddog]

Traction is not the problem. Even crusing at 70mph, the gps is around 60mph.

 

[snowbeast]

Yes i heard this last year,but i only heard the guy took one tooth off,but if two teeth are accurate at speeds around 45 or 50 and remain accurate up to radar indicated 115 or better than i may do this,reason i say the lower speed of 45-50 is this is where the speedo and gps are anywhere close to each other,and even at 60 on the speedo it is around 50 gps or true speed. Now my sled is all stock,and still unstudded so maybe our sleds were spinning at 123-128 speedo because all i was seeing gps at that speed was 108-109 his sled is the apexgt. Any more ideas are welcome...

 

[Tork]

At the Yamaha presentation last Feb, they did say the speedo's would be more accurate. I'd hold off to make sure, then go only one tooth at a time

 

[SledderSteve]

At the Yamaha presentation last Feb, they did say the speedo's would be more accurate. I'd hold off to make sure, then go only one tooth at a time

As I recall, he did a pretty good job of talking around that question. I recognized the tactic as I've been know to use it myself once in a great while. :wink:

I'll bet you a beverage at the next TY Ride that the speedos are still progressively "optimistic" as the speed increases but in the mean time I have a question for the group.

Why exactly do you need your speedo to read accurately into the triple digits?

 

[snowbelt]

Why have one if it's not going to be accurate? A better question is why does Yamaha NEED to calibrate it to read 15mph high?

 

[Tork]

At the Yamaha presentation last Feb, they did say the speedo's would be more accurate. I'd hold off to make sure, then go only one tooth at a time

As I recall, he did a pretty good job of talking around that question. I recognized the tactic as I've been know to use it myself once in a great while. :wink:

I'll bet you a beverage at the next TY Ride that the speedos are still progressively "optimistic" as the speed increases but in the mean time I have a question for the group.

Why exactly do you need your speedo to read accurately into the triple digits?

Beverage? you bet, er we bet. Prolly true, just dont want everybody to be in a hurry to file teeth off.

because


because

the downside is


you dont get as many miles in on a trip
the odometer will read less.

 

[SledderSteve]

Why have one if it's not going to be accurate? A better question is why does Yamaha NEED to calibrate it to read 15mph high?

Pretty simple actually, I believe they do it to make their customers think they're going really, really fast. How many times have you heard sledders at a pit stop or on the forums calling out the numbers they saw on their speedos?

I'm not saying it's right, I just believe that's the reason it's done. Interestingly enough, sport bikes also seem to share the trait.

Weird eh? :itchy: