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1981 RS 55K, fresh rebuilt heads/dual plugged, newly rebuilt/calibrated 140mph speedo/ Motorrad Elektrik dualplug ignition.
Luftmeister 2-2 exhaust.

So for this '81 RS, though running strong, surprises me that I can only attain a top speed of about the ton (+ - 100mph).
Are the '81> bikes that much slower?
It accelerates good, spins up nicely, etc.

My '78 that had a true '77 RS top-end on it would do 125 and even more one a good day with the wind at my back...

Comments please.

I was of the opinion that a healthy airhead will run to the redline in top. If your RS isn't doing this then it might be not pulling as well as it should. 100 mph for an RS sounds well off the mark...

Does the carburetion need tweaking with the non-OEM exhaust?

Do you have the as-delivered final drive? You could be gear limited and not engine limited.

Kurt in S.A.

Sounds slow for an RS. They are geared so high. My R100S will do well over 120-mph with ease.

Can you redline on 5th? Or said in another way, what RPMs are you at in 100 mph?

Far as I know the trans and rear-end are OEM as from the showroom.
Rear-end is a 32/11, speedo is absolutely the correct one fro that drive, albeit not the 85mph one.
I acquired a 140mph speedo from a good source because I wanted to know how fast I was going above 85mph.

I wouldn't say it's reached redline at top speed, but does strain to get much past 100mph.More like 6K+, definitely not 7K.

Are you sure you have the right speedometer?

It would be interesting to put a GPSr in the cockpit and see what that says.

Major Softie wrote:Are you sure you have the right speedometer?

speedo is absolutely the correct one fro that drive

GPS test coming up soon...

Mine is moody. It has hit 120 but decided it didn't like that and now only will do 115 and it doesn't seem to like going over 110. It runs really nicely and will do 90-95 all day.

Chuey