1965 R50/2 - run-in advice wanted

[TimK]

I just picked up this 1965 R50 and the top end is brand new. rebored + pistons + rings + valves. i've read a bit about airhead break-in but i'm interested in opinions. i've also read the original recommendations from a 1966 R60 owners manual (courtesy of Jeff Dean https://bmwdean.com/).

[schrader7032]

Welcome to the forum and enjoy the ride! Generally, the BMW manual is good info. I suppose if you ask 5 owners how to break in an engine, you'll get 7 different answers!!

My thoughts are:
- the first engine start after rebuild is probably the most critical. Once the oil begins to glaze up on the cylinder walls, the amount of friction and "shaping" of the rings begins to decrease. Only when the cylinder walls are non oiled and cool does that shaping really take place.
- for the first few rides, vary the engine speeds and RPM. Accelerate which puts pressure on the rings. Also, slow with engine braking which puts different pressure on the rings. I agree with avoiding high speeds and sustained speeds. Avoid idling.
- change oil often. I did it after the first ride then again at around 100/200 and finally at 500 miles.
- I also rechecked head torque and valve clearances at each oil change.

[TimK]

@schrader7032

when do i drop the pan and check/clean the strainer?

[schrader7032]

I don't think the strainer is going to get all that clogged. I don't remember but I guess I pulled the pan off at least once, maybe at 500 miles. I would fit a number of super magnets in the bottom of the pan to collect any of the ferrous bits that show up.

[TimK]

I would fit a number of super magnets in the bottom of the pan to collect any of the ferrous bits that show up.

the bike has a couple of miles on it. including a very short (< 1mi) test ride by me. i was planning on draining the oil before break in as im not sure what is in there. if i were to drop the pan as well, how exactly would i go about adding magnets?

[TimK]

this is lifted from a thread at advrider.com. given that it speaks of oil filter replacement i am assuming it is intended for later model airheads than mine. this sounds kind of intense, and i am not likely to go out on a 300 mi ride. maybe 2 150 mi round trips on different days.

Keith Patchett's rules for Iron bores covering the first 200 to 300 miles:

1. Fill the tank with hi-test to avoid ping.
2. Fill the sump to the "add" line with 20-50.
3. Perform a tune-up, paying special attention to getting the timing spot on. (You don't want ping.)
4. Pack two quarts of oil, a rag and a spout.
5. Go on a 200 to 300 mile freeway ride, keeping the engine at about 5000 rpm. Do not use 4th or 5th gear.
6. Stop every hour to check the oil level and top up as necessary but don't let the bike idle and heat up. You want to avoid glazing the cylinders and ruining your break-in.
7. Bring the bike home, torque the heads, set the valves and change the oil and filter.

[schrader7032]

If your pan is steel, the magnets will simply latch on to the pan.

As for Kieth Patchett's suggestions, I personally would not do the ride keeping the engine at 5000 RPM...or whatever RPM you wanted. The engine and components are all very mechanical and they will have vibration interactions with each other. At certain RPMs, the engine vibration is higher while at others, the vibration is very little. The last thing you want to do is sit at some RPM which might be hurting the engine components (for break in) or doing absolutely nothing. My position is the vary the RPMs up and down with acceleration and deceleration to make sure all vibration modes of the engine are activated and the components have a chance to bed in properly. YMMV!

[TimK]

i thought the pan was aluminum. i will have to check

[sherman980]

Magnets are a good idea and easy to install in a /2 oil pan. I wouldn't drop the pan first thing just to install them though. I'd wait until the bike had some miles on it, the pan is leaking, or you have some other reason to do so. In the meantime, you can simply put the magnets on the bottom outside of the pan. Given it is steel, they will hold just fine and will still attract any nasty ferrous metal debris from your oil.

[Daves79x]

I've broken in two of these after total rebuilds. An R50 and an R69. I had to be very careful with the R50 as my machinist bored 1st over to only 2 1/2 thou clearance. It really should have been 3 thou. I have 3500 miles on it now and run it fairly hard, with no issues. It is one of the quietest vintage BMW engines I've heard. So knowing how loose the bore is upon rebuild is kind of important. In any case, I changed the oil at about 100 miles, dropped the pan, cleaned the magnet. You Will have some metallic particles to clean up there. I just like to see what's going on with a rebuilt engine. Then another oil change/pan inspection at about 300 miles, another at 500 miles. By then you should be seeing virtually no debris in the pan. Then you can go to 1000 mile changes, inspecting the pan every few changes.

Dave