r60 engine noise

[George G]

Just finished the machine after four years. What fun! 1969 r60 US with Earls. Rebuilt all but tranny.
All went fine outside of chasing down some leaking carb flanges (been there with amals on my brits)
I now wonder about a noise coming from the engine, that I suspect might be from the breather.
This seems to manifest itself during throttle opening above, I'm guessing at about 1500-2000 or so. I've checked the timing and the advance mech, as well as the valve lash and slide mixture setting. All seems in order. I don't think this is pinging.
This is my first older BMW. Is it common to hear the breather on these bikes making a noise somewhat like a ticking or pinging/whistling sound? New rings - 200 miles so far.
Thanks!
george

[808Airhead]

How much of the engine has been "rebuilt"? Need some more info to make some sort of (hopefully) helpful guess. My 2 bikes only make audilbe exhaust and valvetrain noise when running,the valves have a normal amount of noise and are equal on both sides in regards to the valve train clatter,but I do not have the noises you are describing.
Usually a whirring noise is a rotating assembly/crank/cam gears or bearings/trans,etc....Tell us what you rebuilt or reused.

[George G]

Thanks for the reply! Do to lack of special tools, I had the lower end done by Quality Cycles in Alexandria VA. It was reported that basically a good cleaning, along with slinger was about all that was required. Engine has 44,000 miles. Although my only other experience owning a BMW was a /5 about 40 years ago, I do think that this noise might be a little unusual for this machine. It does sound as if it is possibly synchronized with air intake(and therefore rpm, advance, torque load etc.), but is is definately at the front of the engine and does not seem to favor one side or the other.
george

[schrader7032]

I don't recall if the engine breather can be installed 180 degrees out...I think it was possible at some point but the design may have changed. Do you feel any puffing of air coming out of the small pipe at the front left of the engine? If it were installed backwards, then I suspect it would actually suck air and pressurize the case, causing leaking out the various seals.

Another thing at the front of the engine are the timing gears. There is a number stamped on the top of the engine, like +7 or -6 (it could be anywhere between -20 to +20 or so) which indicates the relative spacing between the centerline of the crankshaft and camshaft when the engine was first built. The theory is that over time, the distance between the two shafts actually shrinks do the whay the cylinders move and the explosions at each cycle...it's literally trying to blow the heads off the bike, thus pulling the crankcase sideway and shrinking vertically. Technically during rebuilds, the meshing of these gears needs to be checked. If truly necessary, the gears need to be replaced. However that's a difficult process and gear selection has to be done so as to ensure proper meshing. Most people just reuse the old gears...I did on my R69S with 30K miles.

I'm not suggesting that the gears are the issue, but just saying that besides the breather, that is another thing in the front of the engine that could make noise.

[George G]

Upon looking at my repair ticket, I must correct my last post to say that there were rod bearings, main bearings, a front bearing and cam bearings replaced during rebuild. As the gentleman who performed the work is now deceased, I can not inquire as to any attention that may have been paid to the gear mesh tolerance. He was however very well recommended and held in high regard for quality work in the area, so I can only assume that these were properly fit. If all other possible suspects are eliminated, I will consider the proceedure for investigating the gears. In a few days I will check the breather for possible vacuum.
Thanks for support so far!
george

[808Airhead]

Definitely pull the front cover off and stick a 8mm allen wrench in the end of the generator and lightly rock it back and forth and see if that makes any clacking noises or excessive gear lash......did the engine sit a long time before you installed it?

[George G]

I have pulled the cover and rocked the gears as suggested by 808 Airhead and found no noticable play at all at any position of the crank. Gear set is -2. Engine sat for two years, warm and dry. I do hear and feel the vent exhausting at the appropriate time towards BDC during this rotation by hand. There is a slight amount of oil in the breather tube but no evidence of much of any coating the under side of the bike during riding. As this sound could maybe described as slight pinging, I have rechecked timing and mixture as well as advance details. This noise comes at about 40 MPH with a particular throttle position and leaves about 45 MPH, or with more or less throttle and is synchronized with carburator intake noise. I'm leaning strongly towards the breather and if it could be thrust against somthing at this particular rpm and pressure condition. I have never seen this device and the manual is a little sketchy on it's particulars, describing it only as "loosly fitting on newer models". Can anyone tell me how it is held in place? How does it seal? Against what? Do you think it could scrape? Thanks!
George