Hi Y'all - New K75S in North Carolina

[joshb]

Hey y'all!


Long time lurker here. I just put my first 5,000 miles on the machine and figured it was about time I introduced myself.


Picked it up in Chicago with 9,000 miles, and have been having a blast since. The input and output splines look fantastic (phew), but I have noticed a strange 'friction' feeling and sound between idle and 2,000 RPM in first and second gears. I opened the machine up this weekend to adjust the valve clearances ( exhaust was damn tight at 0.15mm across the board ), threw in some new spark plugs, and balanced the throttle bodies. Now the 'friction' symptoms are completely gone. Has anyone else run across anything similar?


Only other issue is with the tach getting stuck if it's remotely sunny out, but as far as I understand it seems like a pretty common issue?


Any how, hi, and thanks for all of the info and laughs so far.

[Martin]

Greetings from the land of OZ IMHO you have the pick of the litter.
Regards Martin.

[Filmcamera]

What a beautiful bike - welcome from an envious bricker  :clap:

[Chaos]

nice to see an unmolested S!  Sticking tach or speedo needle usually a warped face plate.  I fixed mine with some small shims between the housing and face plate

[Blue]

Paint that battery black.

[joshb]

nice to see an unmolested S!  Sticking tach or speedo needle usually a warped face plate.  I fixed mine with some small shims between the housing and face plate

Looks like I've got a project for this weekend.

Paint that battery black.

Hah. I was actually thinking the same thing when I was picking out these pictures to post. Sticks out like a sore thumb.

[BrickMW]

... I have noticed a strange 'friction' feeling and sound between idle and 2,000 RPM in first and second gears. I opened the machine up this weekend to adjust the valve clearances ( exhaust was damn tight at 0.15mm across the board ), threw in some new spark plugs, and balanced the throttle bodies. Now the 'friction' symptoms are completely gone. Has anyone else run across anything similar?

This is a fairly common condition reported by several other motobrickers, with as many possible causes and solutions. Mine seems to be getting worse which has me expecting to find gearbox issues when I tear it down this winter, but I am still hopeful that I'm wrong, and more so now that you say you have seemed to solve yours.


My question(s) for you is, did you re-shim your valves? If so, what clearance did you shim them to? Did you have a stack of shims on hand? Seems strange the valves be that tight after only 14k miles, do you think that mileage is accurate? Pics are immaculate so I have no reason to think otherwise, just seems early for that issue.


Anyway, if you did, you would be the 3rd I've heard of fixing this grinding/rattle/skipping/groan/vibration with a valve adjustment. Plugs and balance had no positive effect in my case.


Beautiful moto! and Awesome find!!

[joshb]

This is a fairly common condition reported by several other motobrickers, with as many possible causes and solutions. Mine seems to be getting worse which has me expecting to find gearbox issues when I tear it down this winter, but I am still hopeful that I'm wrong, and more so now that you say you have seemed to solve yours.


My question(s) for you is, did you re-shim your valves? If so, what clearance did you shim them to? Did you have a stack of shims on hand? Seems strange the valves be that tight after only 14k miles, do you think that mileage is accurate? Pics are immaculate so I have no reason to think otherwise, just seems early for that issue.


Anyway, if you did, you would be the 3rd I've heard of fixing this grinding/rattle/skipping/groan/vibration with a valve adjustment. Plugs and balance had no positive effect in my case.


Beautiful moto! and Awesome find!!

I didn't have any shims on hand, and my local dealer wanted $15 a pop for them, so I just removed the existing shims and went to town on them with a grinder. I brought all of the intake clearances to 0.15 mm and all of the exhaust clearances to 0.30 mm. I took the machine out this morning, and if I pay super close attention I can still hear the transition from the friction state to the post-friction state, but it's nowhere near as pronounced as it was previously. Like I mentioned previously, during my test rides after wrenching on it I couldn't feel/hear the state change at all. That may have just been my joy in not mucking up the procedure.

[joshb]

Oops. Hit send a bit early on that one.


Regarding the milage: I have all of the previous owner's maintenance records and have no reason to believe the milage is inaccurate.

[The Mighty Gryphon]

I have the noise in both of my K75's.  It comes on between about 1200 and 2000rpm.  On my RT it had progressed to a clank.  I tore the engine down and found that the source is an excessive clearance between the slots and the dogs that drive the K75 balance shaft.  I am pretty sure that is the reason that noise is not present on my K100 since the K100 has no balance shaft, just a rubber cushioned drive shaft for the oil and water pumps..

I have no idea why BMW designed that clearance.  The only reason I could come up with was to allow the balance shaft to float a bit to dynamically balance the crankshaft for a smoother engine at high rpms.   I was able to stop the noise by cleaning the clutch basket and the mating face of the output shaft and torquing the clutch nut to the top of it's spec to lock the parts together.  That was two years ago.  15,000 miles later I can hear the damn noise starting to come back.  While it is most noticeable in the 1200 to 2000 rpm range, there is also a harmonic that comes in around 3200 rpm as well.  It's a lot quieter, but it's there.  It's a good reason to always ride with the rpms above 4000 which is where the fun begins anyway.

Getting all three cylinders operating as evenly as possible to get the most uniform power pulses seems to be the way to minimize the noise, so valve adjustment and idle air are critical.  Keep the injectors as clean as possible.  Since it happens at low rpms, I also wonder if butterfly balance, the forbidden blues screws may have some effect on it as well.

When I tore the engine down to find the cause, I saw that there was no adverse wear on the dogs and the slots where the noise comes from, so I guess that the solution is to keep the engine as tuned as possible, ignore how shitty it sounds coming away from a stop and rev the piss out of it as much as possible.   

[K1300S]

welcome.  nice color.  i have two black S's that bracket yours, at 92 and a 94.

mine makes that rattle between 1200 and 2000.  valve adjust and TB balance had zero effect.  i live with it.


PS - your handlebars need adjusting...angled up too much.

[Martin]

Marshall when I first got my 75s it used to trap my thumbs against the tank on full lock. Slowly over 20 years the bars have been progressively moved up and back to cater for maturing anatomy. :hehehe
Regards Martin.

[K1300S]

Marshall when I first got my 75s it used to trap my thumbs against the tank on full lock. Slowly over 20 years the bars have been progressively moved up and back to cater for maturing anatomy. :hehehe
Regards Martin.

LOL...not exactly a youngster myself....  the factory spec adjustment (with no risers) where the ends of the bars are about 1/4in off the tank at full lock provide the perfect angle for my wrists for hours of comfy riding...even with significant arthritis in my thumbs.

near brick....bars not adjusted correctly(yet), far brick...spot on!

[Martin]

While there is a standard starting position, not everybody is built the same that's why bars are adjustable. The last modification I did to my Brick was to lower my seat and add Jo's special padding.
Regards a comfortable Martin.