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Thread: 1994 K75RT - Valve Adjust

  1. #1
    Dum vivimus vivamus ted's Avatar
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    1994 K75RT - Valve Adjust

    Hi Folks,

    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.
    Ted
    "A good stick is a good reason"
    1994 K75RT
    Moto Pages

  2. #2
    chansuresh
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    Thanks for the post. I have the same problem of loss of power and poor idle, and looking to do the same with LeeF's help over the holidays.
    Quote Originally Posted by ted View Post
    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.
    Suresh

    1994 K75RT; San Mateo, CA

  3. #3
    Dum vivimus vivamus ted's Avatar
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    Sounds like you'll be in good hands!

    Here is the info for Ken:

    Kenneth Lively
    318 S Hart St
    Palatine Il 60067
    polepenhollow@yahoo.com
    847-561-8555

    FWIW, the difference between Ken's valve tools and the $$$ ones from BMW are only twofold - the BMW hook/depress tool has a handle, and the BMW set tool is literally twice as thick. Personally I find the Ken's set to work perfectly.

    I did ask Ken if it were possible to drill a small hole at the end of each of the two tools so I could keep them together on a key ring until needed, I've already played lost and found with the smaller set tool
    Ted
    "A good stick is a good reason"
    1994 K75RT
    Moto Pages

  4. #4
    Benchwrenching PGlaves's Avatar
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    Good show, Ted. I can't imaegine just swapping shims around to get an acceptable result. I suspect he probably made things worse.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  5. #5
    ...never too much lefse sleeper's Avatar
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    Much appreciated Ted

    Just like the rest of Ted's posts, I appreciate this one because:
    1. He doesn't assume a lot of previous mc maintenance experience (I have none but have been learning as I go)
    2. He describes the process completely, in language even I can understand.
    I hope to get similar results when I tackle the valves this winter.
    Thanks Ted
    Robert Horton
    95 K75RT

  6. #6
    Nick Kennedy
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    Good tutorial thanks Ted
    You inspired me to do this..

    Tech question: Is a K100 valve shim kit the same as a K75?
    I have a friend who has a K100 shim kit that he wants to send me, but I've got a K75.
    Thanks

  7. #7
    3 Red Bricks
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    Same shims.



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  8. #8
    Benchwrenching PGlaves's Avatar
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    Quote Originally Posted by 98lee View Post
    Same shims.



    +1
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  9. #9
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    Many Japanese motorcycles use the same size shims. My Yamaha XJ 550 has the same shims as my K. With the proper tools, changing shims is fairly easy. The hard part is finding a new shim the right thickness. When your nearest BMW dealer is 300 miles away, you can't just run down and get one and the Japanese dealers around here don't have a good stock. So valve adjustment becomes a winter project when I can wait for parts. I have found it important to record each valve shim thickness when I have it out or replace it. This makes future adjustment easier (But probably not needed very soon) My Yamaha has over 100,000 miles and two of the valves have never needed adjustment. On a side note, the Clymer manual for my Yamaha says DO NOT use a magnet to remove the shims. They are a case hardened steel which can become magnetized and can then attract small iron particles and cause cam wear. I have used compressed air to dislodge the shims, just be sure to hold a shop rag over the cam
    and valve to keep oil and the shim from flying everywhere.

    1987 K75C, 1981 Yamaha XJ550 , 1980 Yamaha XT500, 1971 Honda Z50

  10. #10
    Benchwrenching PGlaves's Avatar
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    Between us, Voni and I have ridden K75s well over 800,000 miles. I am too lazy to refine that number any further just for the sake of this post. At least 95% of the time I have found individual valves to be within specification. In the first 369,000 miles on my late, lamented, run-over, K75T Old Smokey I replaced exactly 5 shims.

    Which is to encourage any K75 owner to check the clearances even if they don't have the tools or shims yet. When you find a shim that needs replacement then worry about the tools and shims. Old Smokey took the first shim at 60K and the second at 100K. By then I had the "stuff".

    p.s. If you identify a shim you need and can't source it from a dealer, let me know. I will send you the shim you need as long as you promise to send me back the old shim you don't need.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  11. #11
    3 Red Bricks
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    Paul,

    You better be careful with that offer or your likely to end up with a ton of 2.50 - 2.60 and nothing thinner.


    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  12. #12
    Nick Kennedy
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    Well I did it...I took the lower side fairing off my 1990 K75 RT with 28 k on it and checked my valves. Intakes are .16 .17 .17 exhaust .28 on all three. yahoo
    The plugs look great.
    The only drag was, when I put new Bosch plugs in, they were marked "made in India". yuck.
    I saved my old plugs [ made in Germany] and carefully packaged them up in case.
    Thanks Ted for the inspiration!

  13. #13
    Dum vivimus vivamus ted's Avatar
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    Congrats on the good news! I didn't think to check my plugs when I put them in. That said, they opened up so much in 25k miles I may just start checking them once a season.
    Ted
    "A good stick is a good reason"
    1994 K75RT
    Moto Pages

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