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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: xians421 on May 25, 2014, 02:26:54 AM
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Brought my just purchased 92 K75 to a very reputable BMW moto mech. He says he'll need to "go through it. it probably has air leaks and the injector screws are too far out as if somebody tried to just get it to idle" Also called it a Craigslist special. the valves are probably too tight. He wants $500 as a low estimate and has a 25 day wait list. I do most of my own work as long as it doesn't require removing the head. It's my first BMW and the Clymer manual is in the mail. Any suggestions? :bmwsmile
Previous owner provided o-rings for injectors. Is this a hint? He seems kinda clueless.
Symptoms: Likes to cut out as I decelerate to a stop from 4k-7k rpm (the only power band and I knew that going in) forcing clutch release in 2nd and/or carefully throttling to avoid stall. Seems to run alright at idle around 950 -1300 rpm. Mech says it should be much smoother. Seems to me it runs great at 4k-7k but I can tell that pristine injectors will bump it up.
Looking for any and all insight.
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While waiting for your manual,visually check all rubber parts/hoses for cracks or splits. While bike is idling use unlit propane torch around throttle body rubber tubes and see if you notice a change in rpm. Rpm change means vacuum leak. Good luck, almost all problems can be done by you and good advise from owners here. :2thumbup:
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Do it yourself. Look at left rear area of throttle bodies for a ½" approx 3-4" long rubber hose with 2 degree bends. Often cracks, needs replacement. Also remove gas cap assembly and check black rubber support for fuel pump. If soft replace . Beemerboneyard has a kit. Do it before losing the pump. Wish I had known.
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I agree with the posters above, do it yourself. There is nothing magical about a K bike, until it rides like it should. I mean mechanically.
Be prepared, to check all the rubber bits carefully. They are the ones that really deteriorate.
You can pull the injectors and take a look at them. But really check that crankcase vent hose. Even new ones fail fairly quickly. I have been trying to come up with a replacement, but it's a strange shape and requires a pretty thin hose :dunno. I should check into a silicone replacement, although it would be custom I suppose. I imagine they would sell pretty well though, depending on cost.
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+1 on the propane check for air leaks. Idle bike and move it around the various rubber parts. This post is for a K1100 but will give you an idea.
Intake Manifold Rehab (http://www.motobrick.com/index.php/topic,624.0.html)
Also browse thru the Lieberry (http://www.motobrick.com/index.php?topic=666.0), lots of useful info there.
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Thanks everyone. I must say after digging deeper into this site, I may have wasted my money on a manual as almost every problem I can think of is addressed somewhere here. But SRSLY what should one expect from a bunch of fanatical German engineered motorbrick owners/riders? You guys are great and I hope to ride with some of you if you ever get down uberSoCal way. :clap: :2thumbup:
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If you ordered a Clymers manual always double check the torque values with another source....DAMHIK.
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THIS POST (http://www.k1100lt.de/index.php/technik/falschluft) shows the rubber parts that need attention periodically on a K1100
THIS DOWNLOAD (http://technik.flyingbrick.de/images/9/9b/13_Nebenluft_Teile.pdf) has the BMW part numbers for the 2V K's including the K75 for the same parts above. Use the page above to visually identify the parts; use the download to understand the relevant BMW part number for your bike.
You problem sure sounds like air leakage.