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Heat

bikebombs

Member
I will be putting a Spyutnik sidecar on my 1976 R60/0. I am a conservative rider and generally stay below 70 miles an our. Should I experience a jump in the oil temp? My wife and I ride from Vancouver Island to Medicine Hat, Alberta every summer. Last summer we experienced daytime temps of 109 F. degrees. I use Spectro 20/50 semi syn.oil and syn. gear oil I change all fluids usually before I need to. Cheers
 
Other will know more, but I think the oil temps will rise slightly but likely not dangerously. The chair side will likely run hotter as the air flow is restricted and might stagnate a bit. But if you're conscious of all this and you stay on top of things, you'll be fine.
 
Actually the air moves faster between the hack and motorcycle due to the Venturi effect. As the air at speed enters and moves through the confined space it speeds up carrying more heat off. I verified this with a cylinder head temp gauge years ago. Even with a full fairing which is why I decided to check in the first place. You might add a deeper oil pan to get more cooling surface but don’t add a lot more oil. The more oil the more heat builds up. Running the engine at higher RPM so as not to lug it with the chair loaded is important. Finding a sweet spot and keeping the rigs momentum is key. An oil temp gauge is useful as oil can be damaged with temps of 250F or more for long periods. If you operate with oil temps above 250 for extended periods on your trips just dump it and add fresh at any bike shop along the way. Spectro is good oil and holds up well to high operating temps. Have fun.
 
One other thing...

Just based on horsepower, your R60/6 is the minimum engine for a road going sidecar tug especially with an all-metal chair. Your final drive ratio will make a difference. I'm guessing here but I believe the 76 R60 used a 3:36 (37.11) ratio which is what I run on my hack with 5 speed transmission and a 76 R90 motor. You would be hard pressed to get your combination to 70 miles per hour and keep it there. The R65 has a lower ratio FD that will provide ample acceleration around town but that will limit your top speed even more on the highway. Day time temps like you describe will result in the rear tire wearing faster due to temperature, loading / weight and RPM and, your fuel economy will be much lower (maybe 28 - 32 mpg) so be sure to have extra fuel along.
 
Actually, the '76 R60/6 came with a 3.56 (32/9). Agreed, adding a sidecar to a an R60 can be load but folks have been doing it for years with heavier boats including the Urals. An oil cooler may be a benefit. As long as you're not tied up in stop and go traffic or pulling long grades with a heavy load, I wouldn't expect a problem.
 
I’ve never ridden a 60/6, or had a sidecar attached to any bike, but I’d be concerned that adding the 235lbs (unloaded) of a Sputnik sidecar + 50-75% more aerodynamic cross-section will significantly tax the 45hp of a 60/6. Going between Vancouver and Medicine Hat?—being “loaded and pulling long grades” will be your situation.
 
The faster you run the sidecar, the more brakes you will want when the time comes.

Actually, the '76 R60/6 came with a 3.56 (32/9).
That's the ratio used on the 77 R65 I referred to. Original 67 R60/2 sidecar ratio was 3:85. R60/6 makes better power by half again. My first hack was built using an R50/2. It barely had enough power to get out of its own way. But, my 'conversion' using an R60/6 did well with speed limit of 55.
Adding a chair to a BMW was at one time a factory option and the engine and drive line are well suited to this purpose. The only caveat is that after 1969 (the last /2 type frame), the new frames are not generally suitable for sidecar and must be braced and have special brackets for a strong attachment AND steering dampers. A real damper. Again, the issue of adding weight is keeping the RPM in a suitable range - ie. not lugging the engine or pulling high manifold pressure. Your RPM range should easily be 4800-5200 in top gear at 65mph. Oil temps of 190-220.
 
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