Need a motorcycle help...

[malbojah]

Backgound:
Bought a used 1994 Honda CBR 1000F (absolutely LOVE IT). Thing is, the previous owner put a new sprocket on the back (geared down) so now the speedometer reads faster than what I am going and the odometer measures farther than I am going. The speedo and odometer are both measured from the crankcase. Is there anywas to recalibrate the two without having to put the original sprocket back on??

Thanks

 

[Bartman39]

Should be able to go to the dealer and get a replacement gear for the drive on the speedo... (cable driven) The new one can be figured by the ratio of the front/rear sprocket (count the teeth on both gears)... Older auto`s used this type of setup also, I have a range of gears for a turbo 350 (automatic transmission for Cheverolet) that will allow me to use a rear gear of 2.73 to 4.56 (several in other words...)

 

[Zenmervolt]

Older auto`s used this type of setup also

Most new autos still drive the speedo from the transmission output shaft. It's just that in modern cars an electronic sensor is used instead of a cable drive.

ZV

 

[Fausto]

PM sward666 (if he doesn't show up in this thread). He's pretty knowledgeable when it comes to bikes.

 

[HomeBrewerDude]

a work around is to buy a wireless speedometer. not the ideal solution, but a good cheap short term fix.

they work by sensing a magnet as it revolves around with the wheel, so you calibrate the speed/odometer readings by measuring the wheel's circumference.


about 30 bucks i think. maybe more if you get one that is designed for motorcycles.

 

[Bulk Beef]

I didn't deal with Hondas much, but I think the speedo used an electronic trigger driven off the countershaft (front) sprocket, so an alternate gearset would be a no-go. Even it was cable driven, bike manufacturers don't generally make that kind of thing available, so it would still be a no-go. I seriously doubt that there is any way to recalibrate the instruments.

You could try yamahaXS's suggestion, but like he said, it's not ideal. It will probably look really cheesy. I've seen guys use bicycle speedos when they wanted something really minimal, and if you just want to know how fast you're going, that will work. I think most of them only have a two digit readout however. Fausto should know more about those things.

The bottom line is that you're sorta SOL. Sorry.

 

[jemcam]

Go to a speedometer calibration shop. They may know how. Most larger cities have them because cops have to have their speedos calibrated regularly.

do a google search on "speedometer calibration". There's tons of stuff.

 

[Fausto]

Originally posted by: sward666
I didn't deal with Hondas much, but I think the speedo used an electronic trigger driven off the countershaft (front) sprocket, so an alternate gearset would be a no-go. Even it was cable driven, bike manufacturers don't generally make that kind of thing available, so it would still be a no-go. I seriously doubt that there is any way to recalibrate the instruments.

You could try yamahaXS's suggestion, but like he said, it's not ideal. It will probably look really cheesy. I've seen guys use bicycle speedos when they wanted something really minimal, and if you just want to know how fast you're going, that will work. I think most of them only have a two digit readout however. Fausto should know more about those things.

The bottom line is that you're sorta SOL. Sorry.

The bike computer thing goes as follows. Purchase a basic computer...something like this one. They have a magnet that goes on the wheel and a pickup that is connected to the computer. You input the circumference of the tire at proper inflation and the computer extrapolates your speed/distance based on how many times per second the magnet passes the pickup. The tricky thing with putting one on a motorcycle is getting the magnet and pickup set up correctly since the magnet has to pass within a few mm of the pickup to trigger it. You will have to zip-tie the pickup to the fork leg and somehow kludge the magnet (may have to use something other than the stock magnet as well) onto the rim.

Make sure you measure the tire circumference carefully since this directly affects the accuracy of the speedo.

Found a page on this very subject.

And another...

Do a google search for motorcycle and "bicycle computer" (exactly with quotes) and you'll get a bunch of other hits.