What is a good Tachometer for tuning the CB750?

classic Classic list List threaded Threaded
5 messages Options
Reply | Threaded
Open this post in threaded view
|

What is a good Tachometer for tuning the CB750?

cbRider
Hi all,
I am looking for a fairly acurate, possibly digital, tach for tuning the CB750.
What I have is a analog tach used for 4-6-8 cyl engines and at the low readings you get on the bike, which is equivalent to two cylinders, is just not acurate enough.

What is a good, not too expensive, tach? Any recomendations?

thanks,
Karl
Reply | Threaded
Open this post in threaded view
|

Re: What is a good Tachometer for tuning the CB750?

Re-run
Administrator
I think at one time I was looking at getting a sunbeam2 I think is what it was called. It was an electronic tach and pretty accurate and only about $40. I never did but still might sometime. It is analog but went by ignition pulses. See the issue you will have is with the wasted spark system, everything is going to read it as a 2 banger. And so you need to compensate. Another option is a dwell meter. I got one from sears a few years back for setting dwell on points but it also had a tach feature that was accurate. I can use that and not get the sunbeam. It was not too bad, something like $50
The ride IS the adventure. The destination is just to get gas!
Reply | Threaded
Open this post in threaded view
|

Re: What is a good Tachometer for tuning the CB750?

cbRider
Thanks  re-run, one posibility would be an inductive pick-up on a tach and put two ignition wires through the pick-up. One from each coil. That would hopefully take care of the wasted spark.
Another thing I have in mind is to try this  with an analog meter, putting some diodes in line to each coil negative connection.
One way or another I will have a tach setup that reads four cylinders. Sooner or later.

Karl
Reply | Threaded
Open this post in threaded view
|

Re: What is a good Tachometer for tuning the CB750?

Polymer-2
In reply to this post by cbRider
I have the diagram for an electronic tach adapter that you can make from radio shack parts on my web site.
Just 2 diodes and a resistor.

http://polymer52.webs.com/motorcyclediysinfo.htm
Reply | Threaded
Open this post in threaded view
|

Re: What is a good Tachometer for tuning the CB750?

myc0p
I finally found your webpage again!!  GREAT INFO for DIYs

Thank you.