52 replies [Last post]
R50Bill
R50Bill's picture
 Offline
VBMWMO #7334
Miami, Florida
Joined: 11/20/2007
Posts: 45
Newbie!

"Darryl.Richman" wrote:
"R50Bill" wrote:

Nonono, I let it idle from a cold start after sitting for 6-8 weeks, I never rode it around and then let it idle.

What Allan is getting at is that just letting the bike idle, even from a cold start, for more than just a couple minutes, can be bad for the motor.

BMW's aircooled bikes depend on air flowing over the cylinders to keep them within their proper operating temperature range. If you visit a dealership, they will invariably have a large fan that they put in front of bikes while they are setting and synchronizing the carbs.

Gotcha.

Allan.Atherton
Allan.Atherton's picture
 Offline
VBMWMO #2709
Joined: 10/27/2006
Posts: 507
Newbie!

"Darryl.Richman" wrote:

... What Allan is getting at is that just letting the bike idle, even from a cold start, for more than just a couple minutes, can be bad for the motor...

But I was thinking that a cold engine is a large heat sink, and can idle quite a bit longer with heat from the cylinders being transferred to the heads, case and transmission, before it has nowhere else to go.

The best carb adjusting is done on a hot engine, and can go on for many minutes, and that is where I use two large box fans, one angled toward each cylinder. One fan in front of the tire is not so good.

Guenther W once did a restoration for a customer in FL, his first BMW, and knew the person might not be so aware about break-in or idling. So he bored the cylinders with a generous tolerance. As opposed to me, who asked for extra tight, because I wanted all the metal I could get and would take care of it. Sure enough, within 2000 miles, the customer ran into an accident on I-95 in 100 degree heat, and paddled his restoration for an hour. And because of Guenther's foresight, it did not seize.

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.