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Tachometer reading high.
Posted: Thu Feb 17, 2011 3:11 am
by SteveD
The bike:1988 R80RT monolever with electronic tacho. Not my bike btw.
The problem: the tacho is reading high. It's been like this since before the current owner.
Eg; 5,000 RPM at 100 KPH in 5th gear instead of an expected 3,750+ RPM .
FD ratio 3.36.
Any suggestions?
Re: Tachometer reading high.
Posted: Thu Feb 17, 2011 6:41 am
by Kurt in S.A.
One of the on-line BMW specs sites indicates that the monolever RT typically came with the 3.00 FD. In 5th gear, this would lower the RPM a little less than 1000 RPM. Did the 3.36 come with this bike from the factory? I assume that the rear wheel is a stockish tire on an 18-inch rim.
On my /7 with a 3.00 FD, I typically run 4000 RPM at 70 mph in 5th and 3500 would be about right for 60 mph.
Kurt in S.A.
Re: Tachometer reading high.
Posted: Fri Feb 18, 2011 12:07 am
by SteveD
bmbikes has the specs as 1:3.36. This is a bike in Queensland, Oz.
Either way, the indicated rpm is too high, running in 5th @ 100kph. All else appears normal apparently.
Re: Tachometer reading high.
Posted: Fri Feb 18, 2011 12:20 am
by Ross
Sure does sound wrong. The figures that it should be that you quote are what I see on my Tacho.