MKL’s 1974 BMW R90/6 Airhead Archives (May 2004 – April 2008)

April 14, 2008 – 32,300 miles: The R90/6 is sold.

March 2008: The R90/6 makes the cover of BMW Owner’s News Magazine!

November 11, 2007 – 32,211 miles: The bike gets some fresh fluids to get ready for winter season.

• Motor oil & filter change with Dynacycle 20W/50 Semi-Synthetic Blend

• Driveline fluid change with Amsoil Severe Gear 75W/90 GL5

September 11, 2006 – 31,388 miles: A large rock kicked up by a car in front of me destroyed my glass headlight lens, so I had to replace it. I need to buy one of those plastic guards to protect against this in the future!

• 63-12-1-358-147 BMW Glass Headlight Lens

August 5, 2006 – 30,875 miles: The R90/6 gets a new air filter prior to leaving for the annual Airhead “Moss Gathering” in the Poconos.

• 13-72-1-254-382 BMW Air Filter

July 15, 2006 – 30,718 miles: The red “GEN” warning light had started staying on continuously, so the bike went back to Classic Airheads for diagnosis. The original alternator rotor had gone bad, and some new points were required. A good used OEM rotor was found and replaced the original. An attempt to install the Dyna III Electronic Ignition the previous owner gave me ended in failure – there might be something wrong with the system, which I’m sending back to Dyna to check out. The R90/6 is now going to get less everyday-type use, as I’m using my new 2004 R1150RT for commuting duty.

• 12-31-1-244-642 Alternator Rotor (Used)

• 12-11-1-243-555 Points Set

June 16, 2006 – 30,280 miles: I noticed that I had a spare set of new heavy duty advance mechanism springs lying about, probably from the previous owner’s stash that he gave me. So, since I had a few minutes spare time, I installed them. I also added some 3M reflective tape to the rear of the Krausers, for added visibility.

• 12-11-1-356-546 Heavy-Duty Advance Spring (2) installed

June 14, 2006 – 30,049 miles: The original “straight spigot” Karcoma petcocks were rusty and hard to manipulate. Worse, the straws had fractured, leading to a “reserve on all the time” condition on the left petcock… I found out the hard way on the way to Bob’s BMW. 3 miles from Jessup, the bike ran out of fuel with the petcocks in the “on” position, so I switched to reserve – only to find out I had none! So, today, replacements were installed. For budgetary reasons, I chose “rear spigot” Karcoma petcocks, which are half the cost of “straight” replacements. While in there, I noticed that the metal sleeving of the choke cable had worn almost clear through the metal body of the old right-side petcock, so I installed some old rubber fuel line over the choke cable to provide some insulation.

• 16-12-2-307-113 Karcoma Cast Rear-Spigot Petcock (left-side) installed

• 16-12-2-307-114 Karcoma Cast Rear-Spigot Petcock (right-side) installed (PICTURE)

June 9, 2006 – 29,592 miles: I rode down to Bob’s BMW in Jessup, MD to check out the place, and bought a new stainless steel front brake line. While I was out test driving a new R1200RT, the nice folks at Bob’s decided to surprise me by installing the brake line. (Another example of the great service at Bob’s!) The new line made a big difference. Brake feel is now firm and responsive – at least for brakes of this dated technology. I think this is as good as it’s going to get on a bike of this age.

• Bob’s Stainless Steel Front Brake Line installed

June 6, 2006 – 29,295 miles: I replaced the tired, generic 26 AH sealed battery in the bike with a new Hawker Energy Genesis XE16X model. We use these Hawkers at work in our military UPS Systems, and it is very similar to the vaunted “Odyssey” battery Hawker sells for motorcycles. The battery features a metal casing for extreme durability against shock and vibration, as well as extended operation up to 60 degrees Celsius. Expected lifecycle is 8-10 years rated at 25 degrees ambient. This is about double what you would see out of the gel cells normally sold by BMW for the bike. Our controller here at work has had one in his Harley since 1997, and it’s still going strong! And best of all, it was free!! Perks of the job….

• Hawker Energy Genesis XE16X Battery installed

June 5, 2006 – 29,187 miles: The bike is now officially on commuting duty! I am enjoying access to the HOV lane and the excellent fuel economy daily.

• Motor oil and filter change with Dynacycle 20W/50 Semi-Synthetic Blend

• Driveline fluid change with Bel-Ray 80W/90

• Small BMW Roundel stickers added to top of Bing Carbs (PICTURE)

• Formotion “Classic” Blackface clock added to handlebar

• National Cycle Plexistar 2 windshield installed (PICTURE)

May 26, 2006 – 28,027 miles: The bike went in to Classic Airheads to replace the leaking pushrod tube seals, repair the broken centerstand, and check out the front brake assembly (which has never performed well since I got the bike). While there, the tach needle (which fell off) was reattached, the instrument board was replaced, the steering damper was rebuilt and steering bearings adjusted, the rear brakes were readjusted, the shifter seal was replaced, the points were replaced, the valves were adjusted, and the spark plugs were replaced. The front brake was more of a challenge than expected – the caliper was rebuilt, a used master cylinder in good shape replaced my old corroded one, the cable was replaced with a new one, new BMW brake fluid added, and still the feel is weak at best. Perhaps an air bubble in the system? The following major parts were replaced on this latest service:

• 34-11-2-301-705 Front Brake Caliper Rebuild Kit

• 34-11-2-301-358 Front Brake Pad Set

• 34-31-1-234-469 Master Cylinder Cap

• 32-73-1-234-400 Front Brake Cable

• 62-11-1-356-665 Instrument Board

• 11-32-1-250-267 Pushrod Seals

• 12-11-1-243-555 Points Set

• 11-14-1-253-415 Points Hose

• 23-11-1-006-124 Shifter Seal

• 12-12-1-338-145 W6DC Spark Plugs

I am going on a tour of Vermont this coming Memorial Day weekend and will examine the brakes more closely when I return. I also added a new Brown sidestand, and reattached the Krauser luggage to the bike for the tour. The original Krauser mounting system and luggage rack (made of aluminum) was broken in 9 places, but I had it all welded and cleaned up. Everything went on without a hitch.

October 2, 2005 – 27,863 miles: Motor oil change to Dynacycle II 20W/60.

July 12, 2005 – 27,460 miles: While on a trip to Penn’s Cave, PA, the transmission input shaft failed, and took out the clutch in the process. This was due to a lack of lubrication on the input shaft splines, which I foolishly neglected to ever check since purchasing the bike. The clutch was replaced, as was the input shaft and all related seals and gaskets. The driveline fluids were changed again with BMW 80W/90. The list of replaced parts is as follows:

• 21-21-1-234-035    HD Diaphragm Spring

• 21-21-1-234-035    Pressure Plate

• 21-21-1-236-332    HD Clutch Plate

• 21-21-1-231-666    Pressure Plate

• 21-21-1-231-463    6 Clutch Bolts

• 23-21-1-231-516    Input Shaft

• 23-12-1-338-726    Oil Seal

• 23-11-1-338-596    9-Gasket

• 23-12-1-232-681    Seal

• 07-11-9-963-300    Gasket Ring

• 07-11-9-963-200    Seal Ring

• 23-12-1-338-741    Gasket Ring

• 33-17-2-311-098    Gasket

Lesson: Keep those splines lubed!

July 15, 2004 – 25,023 miles: I got a tool tray (none was included with the bike when I bought it) and a new steering damper knob to replace the old one.

• 52-53-1-232-640 Tool Tray

• 31-42-1-236-892 Steering Damper Knob

May 2004: Black 1974 BMW R90/6 picked up with 24,503 original miles.

• Krauser Saddlebags and Windjammer accessories are stripped off.

• All fluids changed, and new air filter and spark plugs are installed.

• Front fork boots replaced. Progressive fork springs replace original stock springs.

• All cables lubricated. Frayed clutch cable replaced.

• Progressive 412 rear shocks replace original stock units.

• Some new Stainless Steel hardware throughout.

• Brown sidestand removed. Stock centerstand added. Stock sidestand missing.