Speedo drive differences

[wayne]

There's been some talk about a lower geared speedo drive that corrected the very optimistic speedo. A member noted that 1 turn of his wheel gave 3 turns of the cable drive.

I checked my late model M and same, 1:3.

Also checked an NOS one I had floating around in storage. 1 turn gives a bit more than 2 3/4. Definitely different gearing.

With a bit of fine tuning and some arithmetic, the drive output is around 93% of the more typical 1:3 drive. That would go a long way to fix the 5 to 8% (tyre dependent) speedo/odo error.

Looks like the altered gearing drive replaced the early one.

Early 1:3 54600-34000 (early "M only" parts book lists this)

Later 1:~2.8 54600-34001 (late Apr '76 parts book lists this for both models)


54600-34001




Ready to roll:




After 1 turn of the main wheel, it hasn't made it back to the vertical which would equate to 3 turns in this test:

[HGH 770N]

Very interesting Wayne.
Are there any distinguishing marks or numbers on the units that differentiate them selves from each other?

[timpa136]

I noticed another identifier in the part number that I don't know.... 000 behind the part number.

Can those numbers apply to the color of parts, anything else?

[wayne]

Jan 28, 2023 5:23:16 GMT -5 HGH 770N said:

Very interesting Wayne.
Are there any distinguishing marks or numbers on the units that differentiate them selves from each other?

That'd be very useful to know. I'll have a look later today Roger. Sun's out, riding this morning!

[multistrada1]

I wonder if there is a GT750 Crossover on this part? I have noticed that my speedo shows about 70 when everyone else is doing 65.
I would have to check with a GPS to be sure.

[hudson]

 My early M models all have the 1 to 3 gear boxes.  My Suzuki price book shows 54600-34000 supersedes to 54600-34001 and then to 54600-08C00 . Modern RE5 parts book shows 54600-08C00 and this number is shown to cover GT750, GT550 and GT380 1973 -77 also 1980-1982 GS450. Looks like it is still available from Suzuki as a valid  part number. Would be interesting to see what the ratio of this latest gearbox actually is. Has anybody attained one by the latest part number ? 54600-08C00

 Just another small side note, when I worked at the Suzuki dealership in the 1970's we sold a GS750 and a GS1000 to a local police department . After a few months they contacted us to complain about the inaccuracies of the speedometers and wanted them replaced under warranty. U.S. Suzuki responded that the speedometers were within the 10 % accuracy required under U.S. import  Rules/Law.


Brian

[wayne]

I think TIMPA has the 08C00 'boxes. He may advise.

For HGH770N, these are the only differences I could find. Old on the bike, newer in hand. No numbers or stampings, just the later 'box has the harsh mould lines smoothed over. Could be a red herring though, nothing to do with early or late. I believe that TIMPA may be able to advise on this as well. He believes he's posted on the Board about them in the past.

[wayne]

Jan 29, 2023 19:35:08 GMT -5 hudson said:

 

 Just another small side note, when I worked at the Suzuki dealership in the 1970's we sold a GS750 and a GS1000 to a local police department . After a few months they contacted us to complain about the inaccuracies of the speedometers and wanted them replaced under warranty. U.S. Suzuki responded that the speedometers were within the 10 % accuracy required under U.S. import  Rules/Law.


Brian

You'd think they'd be a little more helpful given it was a police department and sales may continue well into the future. Oh Suzuki!

[hudson]

 The exploratory deal was struck between the one local police depatment and the dealership, not Suzuki. They had issued many speeding tickets before they were called out for pacing motorist with uncertified speedometers. Many fines were refunded, and I think Suzuki wisely stayed out of that mess. I am sure Suzuki would have responded differently had they been under a contract to supply properly equipped motorcycles.

Brian

[wayne]

I see, a very small market. We only have one police force in each state that serves from border to border plus a federal force which you pretty much never hear of. So a deal with any state force in AU would be a sizeable contract.

I think you're right, given the circumstances, best for Suzuki themselves to stay clear.

[hudson]

 We have local City Police,  County  sheriff's department, State Patrol , and Federal that I think only patrol by black helicopter.

Brian

[timpa136]

This from Wayne,
I believe that TIMPA may be able to advise on this as well. He believes he's posted on the Board about them in the past.

I  do recall posting a difference but have no proof. I come up with very close in turns, about 10:30 to 11:00 short of 3 full turns well.

[wayne]

Thanks Tim, I found two posts by you about the drive:

re5rotary.proboards.com/thread/2478/conversion-complete-speedo-indicates-incorrectly

re5rotary.proboards.com/thread/2074/mpg

[hudson]

  After checking the speedometer drive gear box part number supersede and application cross reference, I mentioned that it showed that 1980-1982 GS 450 superseded to the same part # 54600-08C00 

I ordered 3 GS 450 boxes off e-bay at $12 each.  The results are as mystifying as the RE itself.

1980 Model T 2.8 to 1  same as Wayne's  -34001           1980 S model and 1982 E =    2.7 ( less than 2 3/4 about 2 11/16 )   A gear tooth count maybe in the future.

Brian

[wayne]

That 1980 T model 2.8:1 may be the best overall.

I'm showing 5.6% odometer over read with Battleax BT46 (100/90) on the front. It would correct it to ~1.5% ODO under read. If you had closer to the 8% error with similar tyre sizes to original, the 1980 T model 'box would still be the most accurate correcting to a slight over read (less than 1%).