Topic: CB550 Tach drive ratio?

[freezingprocess]

Does anybody know what the tach drive ratio is for a 1976 CB550? I've looked all over the forum, but haven't found a definitive answer. I've gotten either 7:1 or 4:1. 

-Chris-

[FunJimmy]

Chris

I'll count the gear teeth later tonite and post the findings if you don't get a answer from someone else first.

FJ

[bwaller]

I read this here just a while back. 350/400/500/550's are 20:3.  750's are 4:1

[freezingprocess]

Chris

I'll count the gear teeth later tonite and post the findings if you don't get a answer from someone else first.

FJ

Ha ha- I should have been smart enough to figure that one out. I'm going to try counting them when I get home too. Thanks FJ

[freezingprocess]

I read this here just a while back. 350/400/500/550's are 20:3.  750's are 4:1

Thanks Bwaller-

[FunJimmy]

I read this here just a while back. 350/400/500/550's are 20:3.  750's are 4:1

Brent
I found that info too.

That ratio of 20:3 must be the tach's internal ratio.

[bwaller]

Yea Jimmy, you're right.

[bruisedlee]

sorry to bump old thread, but what tach ratio for cb650?

[bruisedlee]

will these electronic tachs work? http://cgi.ebay.com/ebaymotors/Custom-Mini-Electronic-Tachometer-Gauge-Harley-_W0QQcmdZViewItemQQitemZ140422147441QQptZMotorcyclesQ5fPartsQ5fAccessories#ht_1151wt_679

this is exactly what i'm looking for but it is listed for a harley.  i think it hooks up to the coils?

this might help to see if its compatible: http://www.speedwayinstruments.com/uploads/microTach_instructions_tachadapter.pdf

[Laminar]

As far as I can tell, you need an electronic ignition if you want to run an electronic tach. I tried a few different electronic tachs with my stock ignition-ed 550 and nothing worked correctly.

[bruisedlee]

my 550 has dyna s or is that not gonna work either?

[Laminar]

That's fine, just about any electronic Honda tach from a bike with waste spark will work for you, as will many others.

[bruisedlee]

sorry don't quite understand what you are saying. 

so with my cb550 with dyna s ignition and coils, i should be able to run these: http://cgi.ebay.com/ebaymotors/Custom-Mini-Electronic-Tachometer-Gauge-Harley-_W0QQcmdZViewItemQQitemZ140422147441QQptZMotorcyclesQ5fPartsQ5fAccessories#ht_1151wt_679

[Laminar]

Do a search for "electronic tach" and you'll find plenty of answers.

[FunJimmy]

Those Harley tachs have too low of an RPM range to be suitable on our bikes.
I used a '82 VFR750 electronic tach with my Dyna set up and it's perfect.