R65 BMW + clone ?

[Sibbo]

Has anyone tried to fit a 10 hp Chinese engine into an R65 frame ?

Here are a few numbers from a BMW forum

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


5th gear
55 mph (88.50 kph) = 4000

From those numbers it looks possible if slow .I do have a cunning idea for a simple 25% step up box which would give 95 kmph at 3600.Adequate and 5 speeds would be good .

But i have no idea if a Yamaclone will fit in the frame . Does anyone her have a special based on a BMW?

[realnutter]

I'm not at all sure it'll fit! The BMW chassis is not very deep chested, I guess coz the boxer engine is a/ not very tall and b/ hangs between the rails...

I'm going to have to modify my BMW R100 frame to get my Honda V-twin in.

On the later bikes, the frame number is stamped into the lower right frame rail down near the brake pedal...I don't know if this is true for older bikes, but it will make modification tricky.....

Matt

[Sibbo]

Thanks Matt .I've got an R80 ST now and know where to get a cheap unregistered R65 .

My ST frame is almost identical to an R65 so I can measure things up but the motor would have to go in the way a BMW motor fits , crank in line with the wheels and up on top of the frame rails .

Does anyone have a measurement of a Chinese 10 hp from top to bottom ? As Matt says It would have to go on top as I'm not allowed to cut the frame in the state .

I wonder if the Pursun 20hp would be a better fit ?

[Dan J]

Measurements available here (use LA section)

https://www.dieselbikeforum.com/view ... f=17&t=919

[Sibbo]

Much appreciated Dan ... I'll measure her up .