Author Topic: 79 cb650k gauges on 77cb550k  (Read 383 times)

0 Members and 1 Guest are viewing this topic.

Offline steeldoncb550

  • Full Member
  • *
  • Posts: 75
79 cb650k gauges on 77cb550k
« on: April 08, 2020, 03:06:45 PM »
Hi all question regarding the 79 cb650 gauges and putting them on my 77 cb550. I noticed that the 650 has the dummy lights and tach/speedo wires all connected into one plug rather than all separate with bullet connectors. I'm looking for a recommendation on cleanest install. Should I snip the plug off and add bullet connectors or snip the clip off the 650 wire harness and add the connectors on that? Thanks in advance!

Online Scott S

  • Global Moderator
  • Really Old Timer ...
  • *****
  • Posts: 8,234
Re: 79 cb650k gauges on 77cb550k
« Reply #1 on: April 08, 2020, 03:28:44 PM »
 Are you using the 650 cam and tach drive? The ratios are different between 550 and 650.
'71 CB500 K0
'17 Triumph Street Scrambler
'81 Yamaha XS650

Offline steeldoncb550

  • Full Member
  • *
  • Posts: 75
Re: 79 cb650k gauges on 77cb550k
« Reply #2 on: April 08, 2020, 03:48:28 PM »
Are you using the 650 cam and tach drive? The ratios are different between 550 and 650.
Yes the cam is installed along with the tach drive. Basically looking for the wiring suggestions.

Offline Bodi

  • Really Old Timer ...
  • *******
  • Posts: 5,703
Re: 79 cb650k gauges on 77cb550k
« Reply #3 on: April 08, 2020, 03:51:47 PM »
Are you sure? Honda used one tach ratio up to 500cc and another above 500cc. The CB550 is pretty much a souped up CB500, the ratio may or may not be changed because it's over 500cc. But I do not know.

Online Scott S

  • Global Moderator
  • Really Old Timer ...
  • *****
  • Posts: 8,234
Re: 79 cb650k gauges on 77cb550k
« Reply #4 on: April 08, 2020, 04:16:21 PM »
 The 350/400/500/550 all used the same ratio. 650 and 750 used the same ratio.

  I'd say either wiring connection would work. I like the idea of snipping the connector off the 650 wiring harness and adding them there, as that keeps the gauges stock AND the harness stock, but then you end up with an extra connection in the picture. Plug to plug then going to bullet to bullet.
'71 CB500 K0
'17 Triumph Street Scrambler
'81 Yamaha XS650