Riding an air cooled motorcycle in cold weather

[Walker]

Outside air temp doesn't make much difference in cooling the engine once it gets up to temp.  Heat transfer rates will be about the same for air @30°F or @90°F.  It is the temp at STARTUP that can be critical in terms of performance.  At very low temps the oil is thicker and doesn't flow as well until it gets up to a satisfactory temp.  The colder it is the longer it will take.  Running the engine too hard immediately after startup could result in excess wear because the thicker oil isn't flowing to important surfaces.  Several posters have already suggested a lighter grade oil for this reason.
I'm skeptical that covering the oil-cooler is better than not.  I would be really surprised if the oil did not get hot enough in cold temps.

I agree with you, except that a 60 delta T  on the air will absolutely make a difference in the motor's running temperature!  Yes, the initial heat soak will take longer, but also, the overall running temperature at 90 degrees for the bike will be hotter than at 30.  Can't skirt the physics of heat transfer.

[Walker]

You'd have more problems with the water-cooled motors in cold weather.  They need coolant oils and anti-freeze.

Old Volkswagens have been running around in German winters for well over 1/2 a century.

Engine oils aren't much of an issue now because the multigrades keep a pretty flat viscosity curve across a wide temp range.  If you have a bike that runs a separate gearbox oil then changing to a lighter oil in winter probably helps.

Switching to a lighter weight oil in cold weather is very helpful.  The viscosity of a multigrade is not flat by any means.

Air cooled VW's had a bimetalic air bellows that moved a lever that opened or closed air flaps coming out of the bottom of the doghouse fan shroud to change the amount of air flow across the cylinders depending upon the air temperature.  This enabled a faster warmup in the wintertime.

[JonS]

On the Multistrada forum, it is commonly recommended that you cover part of the oil cooler in cold weather.
 I have never owned a water cooled bike and have never had trouble, even when I lived in WI. Just let it warm up til the motor starts to feel fairly warm on the outside.

[Penforhire]

Just to add, BMW airheads have run year-round with their jugs in the air for half a century without any unusual winter wear.  Carburetion (start-up) and the battery are the only sore spots...

[maddjack]

All I know is when I was running air cooled bikes in cold weather that covering the oil cooler helped or having a oil cooler with a thermostat helped keep the oil in the desired operating range . I ran my machines down to mid 20's no problems but I did always run a lighter grade of oil for quicker starts and warmups in cold(10w40 vs 20W 50 in my case).Main PIA in those days for me was the fact they were all carberated and if not jetted perfect spit and farted till warm....Man I really am getting old remembering this crap

[photomd]

Switching to a lighter weight oil in cold weather is very helpful.  The viscosity of a multigrade is not flat by any means.

Look in the owner's manual. There will be a chart stating what viscosity of oil for what temp. For example, my airhead suggest 10w-40 at anything less than 20F and 20w-50 at anything over 80 or 85F. I never ride less than 25 and inside the garage is usually 5-10 degrees warmer than the nightly low. I do, however, miss on the daily high sometimes so the bike might see 85+ degrees. So it lives with 20w-50.

[ghostwriter]

Yeah no worries, i rode my bandit through iowa winter where it was down around 5 degrees when I started it up.  It turned over super super super slow at 5 degrees, even with 10-40, but once it warmed up ran fine.  even now I ride it about 160 miles to commute twice a week from 27 to 32 degrees, and have no problems.

[motofranz]

Hey all!  I was just told about this forum by a random person I bumped into a few weeks ago and have spent the past few weeks lurking and reading but decided to join today.

My question is this: is it bad to ride an air cooled motorcycle in cold weather (say around 30 degrees F)?  I own an 1984 honda CB700SC and despite the cold weather here in the chicago suburbs today I couldn't resist the urge to take my bike out.  Could riding the bike in cold weather like this cause any damage/excessive wear?  I rode it maybe 7 miles or so.  After I got back I thought about the cold air causing the cylinders to be overcooled preventing them from expanding and thus wearing the rings out quicker. Can this happen?  I hope this is just me being paranoid but I'm new to the world of air cooled engines so I thought I'd ask. Hopefully I didn't mess up my bike! Thanks!

My BMW is air cooled and no matter what the outside temperature is the temp gauge always indicates 5 bars (normal operating temp).