The 1991 BMW K75

This amazing motorcycle has carried me coast to coast five times. It’s a pleasure to ride. Smooth as butter, especially after I learned to tune it. It was 20 years old when I bought it so it’s been necessary to refresh or replace quite a few parts that have worn or degraded over the years. I don’t ride the K as often as I used to, but every time I throw a leg over it I get the urge to head for the horizon a thousand miles away.

It was an “RT” model when I got it in 2011 with a full fairing and BMW panniers, but I took all that fiberglass and plastic off and added police engine protection bars and top-loading aluminum panniers that are made in Idaho.

Maintenance & Modification Log

9/2011 / 83000
Motor oil + filter change, transmission oil change, rear oil change
Rebuild fairing. Rebuild fuel tank cap. Cut windshield.
New rear tire. New clutch cable. New gel battery.
Overhaul forks. New progressive springs, new fork seals.

The ’91 K75 in 2011 when it still had the fairing mounted.

10/2011 / 84000
New plugs, breather hose, header gaskets.
Chevron Techron for 500 miles
Oil + filter change to Mobil-1 / 15w50

Drive bike 3400 miles to RI
Bike covered and trickle-charged until…

6/8/2012 / 87500
Uncover in RI
Change engine oil, transmission oil, rear gear oil, fork oil
Bike starts on first try
Head west to WA
Rear brake master cylinder fails in CT. Rear OEM shock contaminated and fails.
Replace rear master cylinder, replace rear shock, throttle body balance service at Max BMW

7/2012 / 92000
Change engine oil, transmission oil, rear gear oil, fork oil
Lube side stand. Adjust clutch action, side stand springs
Check valves – exhaust shims require adjustment.
Old valve shims: 2.52 / 2.52 / 2.60mm
New valve shims: 2.30 / 2.35 / 2.40mm
Replace spark plugs with NGK

8/2012 – 93000
New rear main seal / clutch o-ring / clutch nut, clean-up clutch — still in spec.
Lube clutch splines, front and rear shaft splines
Add like-new drive shaft and rear drive
Clean out airbox / remove baked crud and dirt from top of engine
New fuel lines, vacuum hose
Bought CarbTune to regularly Sync throttle bodies
R&R BMW front wheel bearings
New front and rear tires

9/2012 – 100300
Ride to Maine, Rhode Island,
Oil Change
Ride to New York, Olympia

10/2012 – 100,700
Motor-gearbox-final drive oil change
Remove fairing, add C bars, new clutch-throttle-choke cables, mirrors, headlight assembly
Add National Cycle F16 windscreen. Put RT bars back on.
Injectors serviced. New spark plugs.

3/2013 – 101,500
Add Hepco-Becker luggage rack
Happy Trails panniers
New OEM Fuel Filter
USB power wiring for Spot GPS + accessories
Add RT-P police crash bars
Add Progressive 465-1101 rear shock

4/2013 – 102,000
Rear drive spline lube. Looked great.
Switch to low seat and S-handlebars.
Coolant flush. R+R right 2x coolant hoses. Tested thermometer.
R+R Radiator fan motor.
500 mile test ride to North Bend – Chelan – Darrington -home
R+R Alternator bushings (monkey nuts)
R+R Crankcase breather hose
R+R Voltage regulator / alternator brushes

5/2013 / 103k
R+R Fork oil. Clean tubes. Switch to 9.8oz 7.5W mix
R+R Front master cylinder with brand new. Bleed front brakes.

6/2013 – 104k
Clean clutch disks, set shift grub screw tight, full spline lube

7/2013 – 105k
New clutch spring, pressure plates, friction disk.
New Rear Tire – Bridgestone SII
WA – WI – NY – RI – (Oil change in RI @ 109k) then back to WA

8/2013 – 113k
New spark plugs. Sweet timing adjustment.
New rear brake pads. Adjust steering bearings.

9/2013 – 114k
Clutch spline lube. Reset transmission grub screw. R+R gear oils.
Oil + filter change
R+R Steering Bearings, fluid block damper grease

10/2013 – 117k
R+R Crankcase cover gasket and bushings.
Front brake caliper clean, new pads.
New Shinko Tourmaster tires (meh)

3/2014 – 117.5k
Oil change + filter 20W-50. Air filter. Replace oil filter cover rubber ring gasket.
Twisty Bovine Ride, Southern California. Averaging 38mpg

4/2014 – 120.5k
Valve check. Old: 2.30 / 2.35 / 2.40
New: 2.15 / 2.20 / 2.25
(lost .15mm on all over about 28k miles)
Tighten steering bearings just a little.

5/2014 – 124k
Tighten steering bearings
Rebuild forks, new fork piston rings, 300cc SAE 5W oil per tube
New rear tire: Michelin Pilot Activ
Repair rear HB rack / new welds
New final drive oil 75W 140, trans gear oil too 75W 90+140mix
Final drive spline lube

8/2014 – 126k
New Crankcase breather hose, intake manifold bushings
New Starter motor brush kit

9/2014 – 128k
Swapped-in Avon Roadrider rear tire / ebay wheel
Valentine: Complete rebuild water/oil pump. New rear brake pads
New front tire: Metzler

10/2014 – WA to RI and back. US12 – US6

11/2014 – 136k
Oil filter change, gearbox, final drive oil change
(recommend final drive/gearbox again no sooner than 150k)
Final drive spline lube.
Put Michelin Pilot Activ back on rear.

1/2015 – 136k
Replaced throttle bodies with ebay 40k mile TB’s. Idling high
R&R intake manifolds. Old ones were in pretty good shape actually.
R&R fuel pressure regulator, fuel line clamps. New spark plugs.
R&R injector O-rings and idle screw O-rings. Idles great now. Smooooth!
Install handlebar hand warmers.
New Odyssey PC680 battery (old PC680 still good)
Magnecor 3508 8.5mm ignition cables
New valve shims:
Old Intake 2.60 | 2.60 | 2.60
New Intake 2.55 | 2.55 | 2.55
Old Exhaust 2.15 | 2.20 | 2.25
?? New Exhaust 2.05 | 2.05 | 2.15
New Exhaust 2.10 | 2.10 | 2.20 (2/15/2014)

Engine knocking at 3500rpm so backed off timing to default.

2/2015 – 137k
Switched to resistor spark plugs NGK DR7EA.
Tested water temp sensor. Good.

3/2015 – 138k
Dyno-tuned, adjust CO at AFM air adjust screw

4/2015 – 139k
Brake bleed F+R

7/2015 – 141k
New Shinko 712 front and rear tires (UPDATE: I like them)
Mobil 1 15w50 oil change / filter / filter cap O-ring
Fixed knocking w/ Autolite Xtreme Sport Iridium Spark Plug – XS4164

8/2015 – 144k
OEM Fuel filter
New EBC rear brake rotor and pads
Lube final drive splines
New muffler gasket and clamp screw
Replace fork oil 10w Honda 290ml

10/2015 – 148k
Engine oil change (w/o filter) in RI / Mobil 1 – 15w50

1/2016 – 152k
Clutch spline lube – Castrol TA Paste
Gearbox oil change – Red Line Heavy Shockproof
Final Drive oil change – Mobil 1 75W90
Engine oil and filter change. Mobil1 15w50
Installed used front brake rotors. 4.05mm thick
Installed Truck-Lite (27270C) LED Headlamp
Installed 2nd horn
New 50a EnDuraLast alternator, rubber bushings
Brake bleed F&R. New F&R ebay brake pads.
New front brake line stainless steel, uses 1.5mm aluminum crush washers.
Honda 10W Fork Oil 290ml each leg
Clean-up relay box wiring, accessory wiring
Added turn signals to tail box / Pelican case
New Osidetiger fuel injectors. Adjust AFM screw for more air.
New in-tank fuel hose, pump strainer, hose from FPR to injector bar.
Adjust and grease steering bearings
Install Cole Hersee starter solenoid (slaves off Bosch starter relay), w/ new 4AWG batt cables
New Happy Trail top box, LED brake light. Remove BMU from relay box.
New coolant expansion tank and hose. Fuel tank-frame grommets.

Next to the Grand Tetons

4/2016 – 154k
New Shinko 712 rear tire.

5/2016 – 156k
Replaced warped front-right brake rotor with my old used oem rotor
Switched to EBC HH sintered brake pads, front and rear
Installed new LED front turn signals
New fork spring retainer O-rings, check fork fluid level
Overhaul forks, damper O-rings, 290 cc BelRay high perf 5W

Switched to Shinko 230 Tourmaster tires F&R (157,000 miles exactly)

6/2016 – 160k miles

7/2016 – 163k miles
Oil & filter change – Mobil 1 15W-50 / 75W-90 in final drive. (No gearbox change)
Final drive spline lube – Guard Dog Moly 525
Re-installed Shinko 712 (3k miles worn)
Removed clutch lever arm, cleaned, greased, reinstalled.
New NGK DR7EA plugs. Adjust AFM screw. Set TPS. Adjust timing and throttle body balance.
Switch to NGK DR7EIX Iridium IX spark plugs
Valve adjustment: new exhaust: 2.00 / 2.00 / 2.10mm

8/2016 – 165k miles
Transmission oil change – Red Line Heavy Shockproof
New Shinko 712’s (F on bike, R standing by…)
Add USB 12v converter up front

Seneca Lake, NY 2016

10/2016 – 166k miles
Rode bike to RI

7/2017 169k miles
Oil change: Mobil-1 15w50
Fork oil change: Bel-Ray 7W 280cc

The K75 is now a cafe racer.

8/2017 173k miles
Removed panniers, rack, wind screen, USB wiring.
Add rear case and tool roll.
Engine oil, filter, gaskets change
Final drive spline lube. Splines look good.
New Shinko 712 rear tire
Bleed all brakes. Bosch ESI6 DOT4

Fork oil change – Maxima 10WT Grade-165/150 Racing Fork Fluid


Remove instrument cluster. Clean up all wiring.