There is some helpful info here http://www.articlesbase.com/automotive-articles/aftermarket-motorcycle-tachometers-517319.html You could also always hire someone.
You can perhaps buy a used portable tachometer by going on to www.amazon.com
www.checkline.com provides the opportunity of comparision of portable tachometers. they offer a complete line of Tachometer, Contact Tachometer and Combination Digital Hand-Held Tachometer.
There are many places online where you can purchase a portable tachometer however, you may want to go to a website like PriceGrabber.com to get the best price.
portable tachometer is used to measure the RPM of rotating devices such as fans and gears. It can also be used to measure the linear surface speed of moving devices such as conveyors and treadmills.
The Garmin Zumo is designed for a motorcycle and so it comes with an easy-to-install mounting kit made for a motorcycle. It attaches to the front near the rearview mirror and is locked into place with screws.
There are many different models of portable tachometers. Most of them are about as big as a large cell phone.
I can be used but it is not preferred as the car device doesn't fit on the motorcycle as well and the voice instructions would be difficult to hear. They do have a motorcycle version but it is slightly more expensive. Here is the link for the Motorcycle navigation. http://www.gpsnavigatorsreview.com/garmin/garmin-zumo-550-35-inch-portable-gps-motorcycle-navigator/
Tachometers count the number of times the ignition fires the cylinders, so a tach from a four cylinder will work on a four cylinder motorcycle. on a two cylinder it will read 50% low.
It can be used to make sure that tapes are being played at the normal speed. It can also measure revolutions per minute for all sorts of objects.
Remove the instrument panel cover. Remove the tachometer retaining screws. Remove the tachometer cable from the back of the tachometer. Reverse the process to install the new tachometer.
It is hard to find people who can repair technical equipment like portable tachometers. However there are many online service that will allow you to mail them and have them repaired for you. Try this site here: www.onlyprotools.com . i am assuming a mechanic would know how to fix that, since tachometers are auto related!
you need a tachometer