Topic: Difference between cb550f and 750 gauges

[Gordo]

Hi guys dumb question time I think the gauges on my 76 cb550f have been swapped out at some point possibly for 750 gauges. The reason for me thinking this is the speedo reads up to 150mph is their anyway to know if the tach is a 750 or 550 as the ratios are different.
Cheers
Gordon

[jlh3rd]

76 CB750 550f gauges are light green, tach redline starts at 9300, speedo says 120....
This is a picture of my 1975 f original gauges. They are the same as a 76 except for the faceplate being dark green. Also, the speedo trip reset knob sticks out of the back, not the side.

[Gordo]

Cheers for the reply I've definitely not got a 550 speedo fitted then, do you know where the redline starts on the 750?

[jlh3rd]

If my memory serves, it’s 8000....I’d have to look it up but I’m heading to a battle of the bulge re- enactment.    Lots of 750 experts on here...and it may have changed in later years....

[PeWe]

I tried late CB500 tacho on my CB750, different gear ratio since it revved much more according to the gauge than it should.
CB550 has same gearing as CB750 or CB500?

[Gordo]

I tried late CB500 tacho on my CB750, different gear ratio since it revved much more according to the gauge than it should.
CB550 has same gearing as CB750 or CB500?

I thought the 650 and 750 had different ratios than the 550
Not really sure though.

[Gordo]

So the gauges fitted at the moment are dark green faces with 150mph on speedo and 9.5k on the start of tach  redline.

[jlh3rd]

It appears,you have gl 1000 gauges...

[FuZZie]

One picture would help, someone will know them for sure. 

[TwoTired]

750 speedo will indicate properly on the 550.  The tach will not and will read lower than true, as the internal gauge gear ratios are different between these models.

The instruments often have a stamp on their backsides to indicate the ratio.  I don't recall the stamp markings off hand, though.

I used 750 dials on a 74 CB550 for many years.  The originals were smashed, 750 examples were all I could find at the time in 75.  I never got any speeding tickets.  But, it would never get to red line on the tach.  I tried many times.  I still don't know why the engine never blew up from over revving it.  I do recall it needing valve adjustment frequently.

Cheers,

[Gordo]

that's the gauges, they seem to be a pair.

[jlh3rd]

A picture is worth a thousands words.....
It appears you have a nippon denso , 750 speedo, and a nippon seiki, 550 tach...
 Switched the speedo to a 750 ...Honda always used the same brand speedo and tach on their factory bikes.....and , it appears 1976 color...

[TwoTired]

A picture is worth a thousands words.....
It appears you have a nippon denso , 750 speedo, and a nippon seiki, 550 tach...
 Switched the speedo to a 750 ...Honda always used the same brand speedo and tach on their factory bikes.....and , it appears 1976 color...

+1 agreed.

I guess I should add that if you change the speedo to 550 origin, the bike will instantly lose like 20 MPH top speed. 
Bwaaahaahaa

Cheers,

[jlh3rd]

So, put the gold wing speedo on and gain 30...

[Bouchard]

people keep telling me that the tacho on the 550 F2 while the same size and attitude as the 750 has different gearing why the hell would Honda do so, it just doesn't make business sense why make different gears for a 550 when you can draw on the same stock for both bikes besides revs are dependent on engine rotation the 750 turn over the same as 550 2 turns of the cam for one of the crank it is the simplest thing in the world to make a tacho with that in mind why would Honda run up huge costs with differing gears and tachos when one would suffice for both .perhaps the Japs just love confusing everyone

[rotortiller]

https://mostynindustries.com.au/speedo-tacho-ratios