Vintage BMW Motorcycle Owners

",,, I'm running W3CC plugs in my R69S. I get them from Vech. I believe the W4AC crosses to the B8HS. You should be able to use a tape measure to determine whether you have short read (1/2") or long reach (3/4") holes." Bosch W240T2 = W4CC Bosch W260T2 = W3CC (was W4C1) and... T2...

... 1969 R69S... It appears that my R69S engine does not have the LK stampings - leading me to believe that these are short-reach heads ... I think the 1969 R69S that I had twenty years ago was not long reach, and all 1968-69 are not long reach. I think BMW used what they had on hand, and it varied.

"... Since R69S heads were exempt from the "butterhead" syndrome, were they also stamped LK by the factory?" The R69S heads used the same alloy as other heads. They are not exactly exempt, but are of a different head design not subject to the same rapid deformation. And the LK me...

Some say straight weight is important for the /2 engine due to its roller bearings which depend on elastohydrodynamic lubrication. The theory is that multigrade oil is good for hydrodynamic lubrication of journal bearings, but viscous single weight oil is best for the elastohydrodynamic lubrication ...

I used AMSOIL 20W-50 in my R69S/Ural outfit from the time it was rebuilt until it was sold in 1991 after 5 years and 10,000 miles. Became an AMSOIL dealer and carried cases of the oil on its rack to rallies to sell. A hundred mile run at 65 mph on a very hot summer's day with a heavy sidecar and a p...

My experience has been that transmissions with sidecar ratio are not really necessary, and are used by very few people because they are pretty rare, and also an expensive change on top of the mandatory final drive ratio change. I had a light Jupiter and a heavy Ural on an R69S with a 26/6 drive, and...

To go with Jeff's file listing the speedo W numbers, here are:
1. A Word file about the speedometer W constant.
2. An interactive Excel file relating tire size, final drive ratio and speed.

Battery strength is very important to starting. This spring, two months after the last tendering, my R27 would not start. Previously it had exploded to life after one double kick. At first I blamed my carb rebuild after installing a Chessel brass-sleeved slide. But after kicking awhile, I noticed th...

Duane only says "My experience with the 3rd and 4th over pistons wasn't good and I quit boring them out that far." It appears that certain pistons were the problem, not the principle of overboring itself. You said "3rd over is about as far as people go. Too much farther... bringing th...

Due a deep rust scar, the cylinder of my basket case R27 was rebored to 4th oversize in 1998. Piston, 70.0mm (+2.0mm) 11 25 0 012 131.2 The engine broke in perfectly, and has run very strongly for the past 9,000 miles. There is no measurable oil consumption, and the oil is so clean at 500 miles that...