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Re: Speed / Revs
Posted: Sat Feb 28, 2015 6:46 pm
by grant81rs
Gidday,
BANG!! on the money Bob, identical symptoms...
So I wonder if the speedo springs can be repaired at all
Re: Speed / Revs
Posted: Sat Feb 28, 2015 6:59 pm
by Bob Bennett
$$$$$s Grant
Instrument Tech should be able to re calibrate for you.
Regards
Re: Speed / Revs
Posted: Sat Feb 28, 2015 7:24 pm
by SteveD
Grant81rs wrote: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.
Re: Speed / Revs
Posted: Sat Feb 28, 2015 7:43 pm
by grant81rs
Gidday Steve,
We shall suss it out first and run a few tests.... This sounds good to me
many thanks
Re: Speed / Revs
Posted: Sun Mar 01, 2015 1:56 pm
by Chuey
grant81rs wrote: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
Re: Speed / Revs
Posted: Mon Mar 02, 2015 12:44 pm
by 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.
Re: Speed / Revs
Posted: Mon Mar 02, 2015 5:08 pm
by grant81rs
Major Softie wrote: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
Re: Speed / Revs
Posted: Sat Mar 07, 2015 4:35 am
by Sibbo
grant81rs wrote: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 ?
Re: Speed / Revs
Posted: Sat Mar 07, 2015 5:26 am
by Rob
Also, the gear set in the final drive could have been changed, with no mention of it on the outside of the case.
Re: Speed / Revs
Posted: Sat Mar 07, 2015 12:16 pm
by Major Softie
Rob wrote: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.