Now for something completely different....BMWK75s

[leafman60]

Lots of good points made.

One thing, maybe already mentioned, is that many of the early year K bikes had a propensity to issue a sizable cloud of blue smoke upon starting. This was due to the cylinder heads being positioned on the left side of the bike.  When the bike was stopped for a while, especially when leaned over on the sidestand, oil liked to migrate down the cylinder walls, past the piston rings and into the head.  This was helped by the vacuum caused by the cooling of the heated combustion chamber.

The engineers tried to improvise a fix with bleed valves made into the pistons to break the cool-down vacuum that liked to suck oil downstairs into the combustion chamber. 

Amazing that big-shot engineers could not anticipate such a problem and did not notice it during pre-production trials.     

[Carlo DeSantis]

One thing, maybe already mentioned, is that many of the early year K bikes had a propensity to issue a sizable cloud of blue smoke upon starting. This was due to the cylinder heads being positioned on the left side of the bike.  When the bike was stopped for a while, especially when leaned over on the sidestand, oil liked to migrate down the cylinder walls, past the piston rings and into the head.  This was helped by the vacuum caused by the cooling of the heated combustion chamber.

The engineers tried to improvise a fix with bleed valves made into the pistons to break the cool-down vacuum that liked to suck oil downstairs into the combustion chamber.   

I had a '91 K75 that never smoked on startup and I usually parked on the sidestand.  My understanding was that after the first year or so of production, BMW began to pin the rings; apparently if the rings were aligned (or nearly so) the oil could seep past them.

As for my K75, I loved it.  It fell victim to a BDC a few years back.  I thought long and hard about replacing it with another one, but decided to go for a lighter bike with more modern tech.

Not many riders have been disappointed with K75 ownership.

Best,

Carlo

[George_S]

We just had the annual dinner of our small BMW club last night. One of our longtime members has 500,000 miles (that's not a typo) on his current K75, I can't recall the model year, and the engine has never been totally rebuilt. He was listed in the BMW owners news an issue or two back as a million miler. Some miles was put on a Suzuki years ago and he needs 40,000 more miles I think on his BMW to have a million on just BMWs. Not too shabby for a North Jersey based rider where we have winters with snow.

[leafman60]

A good resources for prospective buyers-

http://www.motorcycle.co.uk/articles/bike-buyers-guides/early-bmw-k-series

http://www.verrill.com/moto/newkbike.shtml

[Carlo DeSantis]

Here's a rundown of the mechanical changes to the K75/K100/K1100 series from a respected BMW source:

http://largiader.com/k75/khistory.html

Best,

Carlo

PS: For my money, the '94 and '95 models are the best pf breed, so to speak.

[sturgeon]

If you're interested, there's a thread over on advrider about interesting things people have done with K75's

http://advrider.com/index.php?threads/specialks-net-bmw-k75-custom.657248/

[leafman60]

I remember the K75 well.  I was attracted to the sleek, red K75S. 

I took one for a test ride, however, and my attraction waned afterwards.  I was accustomed to twins, was riding a Ducati 900SS at the time.  The K75 seemed like a sewing machine to me. Too smooth. Too sanitized. Also, the low-end punch was not as strong as my twins.  Seemed like I had to really get the K75 spinning up its motor pretty high before having notable punch.

Just my opinion.   

Many of my friends liked them. I do remember the start-up smoking from some of them and the efforts of BMW to fix it even though it was nothing that caused serious problems.

[jbell]

Own a '92 K75RT since new.  62K miles.  Agree with most of the previous good reviews.  I've had a few problems with mine, ABS computer replaced under warranty and the main computer replaced at about 45K for $150 for a used one.  Never had to trailer it home.  Do my splines every 15K and at 60K, they all looked good. Oil filter (5K) is a little messy to get to but the fuel filter (15K) in tank is easy to replace.  Plugs (10K) are easy to get to and checking valve clearance (15K) is fairly straightforward.  I replace coolant and flush brake fluid every other year,  tranny and rear drive with Mobil 1 every 10K.   I'd like something newer with more power but this bike does everything I really need and just keeps running smoothly.  Average about 45 mpg.

[sdcr]

The clutch splines are critical. W/abs and a lift it took ~8 to 10 hours to pull and re-install. The splines are on the trans, mainshaft. Once the female splines on the disc begin to wear it all worsens over time and miles. I put 7 clutch discs in mine. About one every other tire change. bmw said there was nothing wrong and it was normal wear.
 R3~

So, just to be clear, are you saying it takes 8-10 labor hours to do the Spline lube? I've had this Done at my BMW dealer on my R1100 RS, and IIR , it was something like a 2.5 hour job. Is the K75 setup so different that it take up to 7.5 extra hours?

John

1983 Le Mans III

[Carlo DeSantis]

So, just to be clear, are you saying it takes 8-10 labor hours to do the Spline lube? I've had this Done at my BMW dealer on my R1100 RS, and IIR , it was something like a 2.5 hour job. Is the K75 setup so different that it take up to 7.5 extra hours?

I do not have experience with spline lubes on an ABS bike, but I have done it several times on non-ABS K75s and K100s.  The first time around there will be extra time needed because -- well -- it's the first time.  After that, the job is 2 or 3 hours at most.  That's in my garage with a bike lift table.

Be sure to get a replacement mica exhaust gasket from the dealer to replace the one that will fall apart when you pull the muffler.  It also helps to have some clutch locater pins if you're doing the job by yourself.

Best,

Carlo

[cookiemech]

Be sure to get a replacement mica exhaust gasket from the dealer to replace the one that will fall apart when you pull the muffler.  It also helps to have some clutch locater pins if you're doing the job by yourself.

Cheaper to just buy three copper gaskets for header/cylinder head junction and remove the entire system when doing a spline lube.

[segesta]

LBC Tenni: great looking bike, nice job.

[Carlo DeSantis]

Cheaper to just buy three copper gaskets for header/cylinder head junction and remove the entire system when doing a spline lube.

Never compared the cost, but a couple of things to remember: (1) probably good to replace the mica gasket as PM anyway and (2) it's waaaay easier to pull the can vs the whole system -- especially since the the mount studs/nuts at the heads are often rusted tight!