Join Date: Nov 2006
Location: Livingston, TN, USA
New owner of 1987 K75- with questions.
Hi everybody. I've enjoyed reading the forum today, have read all I can find about the K75.
I just bought a 1987 K75 (I think it's just the K75, no suffix on the manufacture plate or on the tail of the bike). It has only 14,000 miles from the previous (original) owner, who traded it in for a new Suzuki not too long ago, as I picked this one up at the local Suzuki dealership. Trading in my 1997 Suzuki LS650P Savage, I paid $1,500 for the Beemer. I think it was a good trade.
(1) The bike runs slightly erratically at highway speed, mostly after warming up. The engine will surge, sometimes getting full power, then not getting full power-- misfiring is what it sounds like. It makes for a jerky ride down the highway. It seems as if there's a fuel delivery problem. I have ordered a fuel filter from the nearest BMW Motorcycles dealer, which should arrive via FedEx by Monday morning. If this doesn't fix the problem, the dealer said to look at the spark plugs and all the hoses, as the L-Jetronic injector system is supposedly very sensitive to vacuum leaks. Anybody have this problem before? Does this sound like a good plan of action, for the time being?
(2) Brakes are grabby at relatively low speeds. I notice it mostly as I come to a slow stop at stoplights in town. It feels like a thick spot in the disc or a rear drum out of round (yes the bike is drum rear brake), as you come to a stop it's sorta the inverse of the engine surges. The brakes get strong in one spot each rotation, or at least that's how it feels. I plan to change the brake fluid and see if that cures it. Would old fluid mess with the ABS and cause such a feeling? Is this natural for the older K bikes? Should I check the discs up front to see if one's out of round or something? I would think the surge would be extra-noticable at highway speed if there was a disc out of whack.
(3) Oil capacity: Four quarts? The owner's manual supplied was from a K100, not a K75. I have read elsewhere that it's four quarts, but questioned the reliability of the site.
(4) Idle speed is a bit low (showing around 900 RPM). Could this be a result of a dirty fuel filter? If not, how do I adjust it?
This BMW is my second bike, after spending a couple years on "Zook," my customized Suzuki single cylinder. I had been keeping an eye peeled for an F650, in keeping with single-cylinder theme, but couldn't pass up the deal on this K75. I think, if I can get it running smoothly again, I won't regret the purchase. The previous owner was an older gentleman who only took it on a handful of longer rides each year, while the rest of the time it stayed parked in his barn. He was a regular customer of the local shop where I bought the bike, buying a new battery about once a year because he didn't have a place in the barn for a battery tender.
Thanks for reading, and looking forward to the experience of owning a BMW cycle,