Speed / Revs

[grant81rs]

Gidday,

BANG!! on the money Bob, identical symptoms...

So I wonder if the speedo springs can be repaired at all

[Bob Bennett]

$$$$$s Grant

Instrument Tech should be able to re calibrate for you.

Regards

[SteveD]

At 110kph on the speedo, the GPS shows 112kph @4500rpms - is this normal or not??

Well that confirms the speedo isn't too bad, but the tacho is reading high.

Three things to contemplate Grant. Assess, repair or replace.

1. Substitute the parts to see if the problem replicates. We have the parts so doing that is easy enough. Just tedious. When we next catch up, I have a do-dad that measures rpm. We can compare real rpm to tacho reading.
2. If one of the instruments, speedo or tach then shows that it's kaput, I can take it to Otto @ Ringwood Instruments for assessment. He does Motometer, but I'm unsure what he charges. He should be able to do something as overall the things are grossly intact.
3. Save up for replacements. They're out there, but they're getting expensive, and second hand they might have similar problems.

[grant81rs]

Gidday Steve,

We shall suss it out first and run a few tests.... This sounds good to me

many thanks

[Chuey]

Gidday Steve,

We shall suss it out first and run a few tests.... This sounds good to me

many thanks

Or try what I do. Cuss it out first, and then run to the store and get a new one!

Chuey

[Major Softie]

I would check the tach against an electronic meter before I assumed, I went a bought a new on,e or had it worked on, just as you checked the speedometer against the GPS.

[grant81rs]

I would check the tach against an electronic meter before I assumed I went a bought a new one or had it worked on, just as you checked the speedometer against the GPS.

Gidday,

Thank our next plan of attack MS... Will let you know the result when it happens

[Sibbo]

Gidday,

When cruising at 110kph on the speedo, the 78 RS shows 4500rpms on the tacho, is this normal?

The numbers stamped on the final drive are 33/11

It has been a while since a rode one of these earlier bikes and I cannot remember what my 81 RS used to do

Any thoughts!!

That's about the revs/speed ratio I have on my ST , do you have the correct final drive ?

[Rob]

Also, the gear set in the final drive could have been changed, with no mention of it on the outside of the case.

[Major Softie]

Also, the gear set in the final drive could have been changed, with no mention of it on the outside of the case.

Exactly why I was saying not to assume the tach was off without checking it against another known good meter.

I suppose checking the turns ratio of the wheel to drive shaft would be a good thing to check to make sure the stamped ratio actually reflects what's inside the drive.