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I've been looking at an old ,rather derelict R65 and wondering about uses or the possibility of a rebuild .

How many mph or km per h does an R65 do per 1000 rpm , just so I can compare it to my ST .

As requested by NC Steve, I went out today and got some speed readings from my GPS receiver and noted the engine speed.
Due to weather conditions, I couldn't take it much above 75, but it appears that 5th gear is 500 RPM for every 5 MPH.
This is a '79 R65 with a 31/9 stock final drive, and Bridgestone Spitfire tires.



3rd gear
30 mph (48.27 kph) = 3000
35 mph (56.30 kph) = 3500
40 mph (64.36 kph) = 4000

4th gear
45 mph (72.40 kph) = 3750
50 mph (80.45 kph) = 4000
55 mph (88.50 kph) = 4750

5th gear
55 mph (88.50 kph) = 4000
60 mph (96.54 kph) = 4500
65 mph (104.59 kph) = 5000
70 mph (112.63 kph) = 5500
75 mph (120.68 kph) = 6000

Wow ! that was quick ! Thanks very much Rob , it appears that an R65 is quite a bit lower geared than my ST .Possibly more than I would prefer ,after my ride today I have to admit I'd really like a higher 5th on the ST .

R65 final drive .1: 3.44

ST final drive. 1 : 3.36

I am pretty sure that all 3 generations of R65 ('78-'80, '81-'84 and monoshock) had different final drive ratios.

BTW, that post was from a few years back on the R65 forum, hence the quick reply.

Still quick !

I don't remember the rear end ratio of my R65 but I think it's higher geared than Rob's. I think 4,000 rpm is nearly 60, 5,000 is around 70, and 6,000 is a bit over 85 which is as high as mine used to read. I've had it up to about 7200 rpms a couple of times just to see if it would do it.

enigmaT120 wrote:I don't remember the rear end ratio of my R65 but I think it's higher geared than Rob's. I think 4,000 rpm is nearly 60, 5,000 is around 70, and 6,000 is a bit over 85 which is as high as mine used to read. I've had it up to about 7200 rpms a couple of times just to see if it would do it.

And keep in mind Sibbo, my road speeds were measured using a GPSr, while Ed's are most likely with the Motometer.
I did see a '82 on eBay - it had a 32/9
http://cgi.ebay.com/ebaymotors/BMW-Fina ... 0507159480

That's about 6% higher than the norm ,that would be good !