About 7 weeks ago I brought my K75 to a local shop for a valve adjust so I could watch it done. Unfortunately the tech had no replacement shims and ended up swapping several (ok all) around to try and find a combo that worked. Needless to say over the last 800 miles I noticed an immediate drop in gas mileage, harder cold start, and loss of power, especially roll-on. I decided to redo it, and do it right.
I pinged LeeF and PaulG, two of the most knowledgeable guys around when it comes to K75s, and unloaded with questions. Lots of them . I assembled a bucket of tools I would need, starting with the high quality and easy to use valve adjustment tools from Ken Lively. For $28 this is a bargain! He doesnt advertise so google his name, these are a must have. I sent off the PayPal and had the tools with a guide for using them within a week. Then a stop at Harbor Freight. There, armed with a bunch of coupons from the website and $20, I bought a car antenna type magnetic pickup, a set of mini-screwdriver type picks, a digital caliper, and a magnetic bolt tray. I fired up Amazon and bought a tube of permatex ultra black, a tube of copper anti-sieze, and a set of feeler guages. Then from the dealer I ordered the inner and outer valve cover gasket, and replacement rubber valve cover bolt nubbins, uncharacteristically inexpensive I might add. From Sears I had my Craftsman Mechanics tool set with neat case I got Black Friday. And of course, a complete K75 tool kit.
My original intent was to pull the cover, measure the gap and each corresponding shim size, figure out the match then make a run to a local dealer for shims. Then fortune smiled on me and I noticed my local club was having a Sunday tech day, and better yet, at a local dealer. So this morning I left early to give the bike time to cool (not hard in 40-degree windy weather). After three hours outside the bike was nice and cool so I wheeled her in to the service area and set up shop in a corner as all the lifts were taken.
Taking the side panel off to access the valve cover on an RT is easier than it looks - three screws for the trim piece, two screws for the fairing pocket, two screws at the radiator, three screws inside at the top, then two bolts. This first time it took me 45 minutes or so, I could do it again now in less than 5. The big magnetic dish really shines here, easy to keep the bolts and screws organized. I loosened up the fairing support bolt that hangs over the valve cover, then removed all the valve cover bolts (replacing the rubber nubbins with new ones as I went.). With that, the valve cover popped right off and about a half a cup of oil drained out into the drain pan Battley Tech Extraordinaire Sean had placed underneath. On Sean's advice i also pulled the plugs, i didnt think it was necessary as they had been changed 25k ago but they had replacements at the dealer so why not. Turns out it is a good time to change the plugs not only because they probably need it (mine sure did) but it makes turning the engine to rotate the cam lobes easy.
A word about Sean at Battley's BMW - this guy is simply awesome. Incredibly knowledgeable about classic K bikes, friendly and very (VERY) patient - I could not have done it without his generous help. OK, I could have but it would have taken me three times as long and that does not include calling LeeF at least twice
I measured my first exhaust valve and it was tight. Very tight. Sean brought his shim kit over and I put Ken Lively's tools to use - the hook tool to push in the shim, and the retainer tool to free it from the bucket. I used the curly end pick to free the shim, then the magnetic pickup to pull it out. The first took me a good 15 minutes to set the tool and extract the shim, by the end I could get one out inside of a minute. I measured the extracted shim with the digital caliper and dropped two sizes, guiding it in with the magnetic pickup, positioning it with the pick, then releasing the valve tool. Then I re-measured it - the trick BMW valve feeler guage is thinner at the first part, the minimum setting, and thicker in the middle, the max setting. It was a perfect fit, just on the loose side of things. I repeated moving the cam lobes with a 19mm open end (being very careful not to let it touch the head) for all six valves. Then I went back and measured each again, replacing one exhaust shim that was a little too loose. All in all, I replaced 5 of 6 shims, no doubt due to the musical chairs the previous Tech had done trying to find a good combo (and failing miserably...).
I then replaced the spark plugs - the gaps on the ones I took out were much more open than the correctly set BMW (aka Bosh X5DC in a BMW box) yet checked nonetheless ones that went in. A tiny little bit of copper antisieze rubbed into the threads, then carefully guiding them and screwing in by hand until the wrench is needed. Then came the fun part, cleaning the oil and sealant residue off the valve cover and head mating surface . Luckily it pretty much just rubbed off with a shop rag. New sealant in strategic locations, new half moons, and the valve cover was on and happy (*gently* screw in the valve cover bolts until they just bottom out, then stop!). On with the Tupperware, find the key (under the seat LoL), and...
Then came the moment of truth. It started, it didn't leak, and it idled so sweetly. I wasn't even out of the parking lot when WOW where did all this power and responsiveness suddenly come from?!?
The correct valve adjust and new plugs made a HUGE difference in the bike, and it wasn't hard at all! It did take time, about three hours total, but I bet I could do it in under an hour next time.
Thanks to LeeF and PaulG for patiently answering my questions, and a huge shout out to Sean at Battley's BMW, a truly competent tech who knows classic k bikes and more importantly is just a really good guy.