the speedo on my 93 900 seems to be off, by a good 10 mph or so. its the old cable driven setup, I didnt know if there was a way to correct this? or if it just is what it is. Or is it possible something in the system is wore out?

 

For some reason motorcycles have notoriously inaccurate speedometers. They indicate faster speeds than you're actually going. Usually the inaccuracy is a percentage off, meaning the faster you go, the greater the difference between actual speed and indicated speed. Is this the type of difference you're experiencing ?

 

to a point.. mine is actually slow, I never really payed attention. My wife was behind me in our truck the other day, and when we pulled over she asked me what was wrong.. I said.. "nothing why?" .. so commented about how slow I was going.. It led to a run behind her on the highway, while she was doing 60, and me right behind her, my speedo said I was doing 75. .. However in town, If I use that rule, and go about 40 in a 30, I am always coming right up on people.

Guess its time to strap the GPS on somehow and see where I really stand throughout the range.

I just don't want to get a ticket for thinking I am going the correct speed.

 

I've found most bikes are around 10-12 percent off. Most bikes I've ridden indicate 60-62mph when your actually only doing 55 mph.

Your descrepency does seem a bit higher than normal though. Is your speedo cable attached to your front wheel? Are you running the correct size tire? You may also want to investigate the number on the speed sending unit. Its possible someone changed it with a speed sender from a different model bike. they have been known to freeze up and require replacement.

Also, as IdoDirt said, its based on a percentage. So if your doing 75 on your speedo but actual speed is only 60, your speedometer is 20 percent off. you would have to travel about 37mph to equal a true 30 mph.

I would strongly suggest hooking up your gps like you said and see what your indicated speeds are at 25,35,45 and 55. that way you will have a good idea of where you truly need to be.