Spedo is 15 mph slow. WTF!

[christianguitarest]

So I just got a 2000 katana at the beginning of the month. After 3 days of riding found a whole bunch of stuff wrong. After getting new chain and sprocket, which the new ones are factory spec (15 front, 47 rear). If I want to go 65 I have to drive 75 on the spedo. At 75, I have to go 90 on the spedo. Any way to fix this?

[05RedKat600]

Do you have a 600 or a 750?

[il_ragazzo]

yeah the speedo uses the hall effect sensor on the counter sprocket. This only applies to katana's made after 98. so a speedo healer should solve your problem. but if you went back to stock gearing then you should have a healer already installed if the speedo is now wrong and was not before.

[05RedKat600]

So I just got a 2000 katana at the beginning of the month. After 3 days of riding found a whole bunch of stuff wrong. After getting new chain and sprocket, which the new ones are factory spec (15 front, 47 rear). If I want to go 65 I have to drive 75 on the spedo. At 75, I have to go 90 on the spedo. Any way to fix this?

Another question, how did you verify your speed? With GPS I hope and not compared to someone else's bike?

[KAT TOY]

mine shows faster than actual. more so with 160/60. checked with GPS.

[scottynoface]

Speedohealer.

[christianguitarest]

checked with gps and a car, results were simular enough. Its a 600 katana and I guess I really have no idea what the front sproket is now that I think about it. Im going to call the dealership that repaired it for and invoice and see what I can see. Ill check out the speed healer sometime when I have $120 for a new toy, for now our new baby we just had with complication is posing a $42,000 bill over my head so well see after we pay our part and insurence does theres what toys if ever again ill be buying, LOL. At least she let me buy the bike 2 weeks before we had our baby, most guys sell theres.

[KatanaGSX92]

Check out SpeedoDRD. It performs the same functions as the speedohealer but is only $79.95

http://shop.12oclocklabs.com/index.php?route=product/product&product_id=59

[MikeyZ]

but if you went back to stock gearing then you should have a healer already installed if the speedo is now wrong and was not before.

BAM.

This should be true. If you just replaced your chain and sprockets and went with stock- Are you sure its stock? AND the speedos still off- then you already have a healer on there from the previous owner.

[scottynoface]

Stock is already off by 5-10% from the factory...

[MikeyZ]

Stock is already off by 5-10% from the factory...

The way I read it was that it was fine before he got the chain and sprockets installed...

ah who cares? suck it up or get a DRD

[steves]

GPS is not an accurate representation of speed, although it's not common for a stock speedo to be off 10-15%.

Much of the GPS accuracy will reside in how good your receiver is.

GPS works by sampling, or taking readings over time. Most algorithims tend to calculate speed by measureing distance traveled in a straight line. most roads aren't perfectly straight. The other thing to take into account is movment along a Z axis. I don't know any GPS's that account for elevation when doing the speed calculation.

[cintidude04]

My zumo 660 does steve.

[MikeyZ]

GPS is not an accurate representation of speed, although it's not common for a stock speedo to be off 10-15%.

Much of the GPS accuracy will reside in how good your receiver is.

GPS works by sampling, or taking readings over time. Most algorithims tend to calculate speed by measureing distance traveled in a straight line. most roads aren't perfectly straight. The other thing to take into account is movment along a Z axis. I don't know any GPS's that account for elevation when doing the speed calculation.

I would assume one would test with a GPS by going straight down the highway and holding it at a steady number for a few seconds. It would get EXTREMELY close- close enough that nobody would ever notice.

[steves]

No it's not, and that's not the case.

I don't think I have data handy, but my Garmin allows me to download traveled route data and display it overlayed on a map. At higher speeds, your sample rate becomes smaller because it's more difficult to manage a lock on more than 2 birds.

So, what I've found is that in the overlaid map you'll see a "line" drawn between two points which represents the route, and the line does not follow the path of the road. GIS data for known entities such as highways is very good in almost all the commercially availibile mapping software.

Your interpretation of "good enough" may still be off by 5 or more percent, so it's not an accurate measure.

My zumo 660 does steve.

It accounts for elevation change in the route details, but I highly doubt the speed calculation shown realtime does. I'd like to see that claim.