Left cylinder:

• rocker arm axial play settled to 0.10mm play at the rear rockerarm, 0.07-0.08mm at the front -> re-shimmed both to a little less than 0.05mm
• valve lash slightly increased to 0.15/0.10 (initial setting 0.12/0.06) -> corrected

• rocker arm axial play no change, virtually zero play
• valve lash (initial setting 0.12/0.06) less than zero at intake and slightly increased at exhaust -> corrected

• Left exhaust valve clearance is slightly decreased, right intake slightly increased, seems the heads have settled, so I have corrected the clearance and will not retorque the cylinder head nuts for now
• fuel consumption so far is just below 50mpg using mostly secondary roads
• oil consumption is at about 0.5 liter per 1000km (1/2qt per 600mls) at the moment, but that can go down with more miles being ridden
• compression at 10.25/10.6bar (150/155psi), measured incorrectly with Bings attached (but I only wanted to have a qualitative statement on the difference between the two cylinders)

• valves are chattering nicely, heads have settled
• fuel consumption at around 45mls/gal on a recent 2750km (1700mls) trip (tailbag only)
• oil consumption at about 0.3 liter per 100km (1/3qt per 600mls)
• amazing overall performance and reliability.
• plugs do show signs of blistering/pitting indicating too hot plugs (used Bosch WR7DC on top, NGK D6HA on bottom plugs), colour indicates a lean condition that needs correction

• one 1700mls trip to New England, trip report here: Fall 2008 in New England
• one 5000mls trip to KS/CO/NM/TX/OK, trip report here: Grand Fall Ride 2008
• Valves checked at about 10,000km/6,000mls: the intake valve clearance of both valves was unchanged, exhaust were tight at about 0.05mm/2tho (initially set at 0.12mm/4tho), so far I have not retorqued the heads
• fuel consumption at 36mpg avg. fully loaded (2 bags, tailback and tent/sleeping bag)
• oil consumption reduced to about 0.2l/1000km (0.2qt per 620mls)
• spark plugs have good color now and heat range seems ok as well (running BP8ES on top and D6HA on bottom plugs)
• couple of casualties/minor inconveniencs:
  • sidestand needs a minor fix (bent, but usable)
  • center stand needs a major fix (bent, not usable with full luggage)
  • right side pushrod tube in the head is leaking oil, need a fix
  • both driving lights gave up under vibration, need to make a rubber mount
  • my GPS died, most likely due to vibrations
  • brake and taillight act weird in rain
  • the ignition switch isn't waterproof and acts weird in rain
• spark plug appearance and other dual-plug related observations after the trip: http://www.stephenbottcher.net/BMW/jettingR100GS.htm

It looked like a material problem to me (Excel), so I contacted the guys at Woody's Wheelworks who put the wheel together for me about 7700mls and 11 months ago. Remember, it was a design featuring a 1/2in offset to the left to allow 130 tires (Airhead GS sizes) in a monolever swingarm. Zach at Woody's was very helpful: his first assessement came down to an excessive stress of the particular area due to two facts: the rim design (non-dimpled, about 5mm rim thickness at that point) and the stresses induced by offcenter cross lacing. He had never had this problem before, but then, this is the first time he tried this kind of application. We are still communicating the best course of action but it might be necessary for me to go back to a configuration similar the 1981-1987 stock design, but using a 2.50 x 18 rim, either x-laced BMW OEM (oilhead GS) or centerlaced Excel. There is a certain advantage to it in another area: to compensate for the smaller rear wheel and tire aspect ratio, I had the (1988 GS) front forks height-reduced by moving them about 1in further through the triple tree, thus reducing its travel as well. So, going back to an 18in wheel would eliminate that restriction too.

So first, I figured out the availibilty of 18in rear dual sports tires. The results were encouraging:

• Dunlop D606, size 120/90-18, 30/70 (knobby)
• Metzeler Sahara3, size 120/80-18, 60/40
• Pirelli MT90 Scorpion A/T, 120/80-18, 80/20
• Avon Distancia, 120/80-18, 80/20
• Continental TKC80, 120/90-18, 50/50
• Maxxis C6006, 120/8-18, 60/40
• Kenda 270, 4.5 x 18 (115/100-18), 70/30
• Mefo Sport Explorer, 120/80-18, 50/50

Another possibility is the use of a dimpled rim that is reinforced in the area of concern. I am waiting for Woody's confirmation.

I don't.

I also looked again very carefully at the hub design which really supports X-lacing best, due to the directional spoke holes as mentioned before.

Based on the above, I have decided that I will have the rear wheel repaired using a (front R100R) X-lace 18 x 2.50 rim that will be laced slightly offcenter, something like 1/4in or thereabouts, just to get some additional clearance for knobbies. That'll put my worrying mind to rest: BMW must know something and the X-lacing has some merrits.

On a positive note: using 120/90-18 tires I will result in more than 1in additional clearance in the rear, so I will be able to raise the front as well by 1in (the amount the forks are currently extended through the top triple tree to account for the smaller 17" wheel).

The parts finally came back and as usual, the workmanship was excellent and the hours of preparation and measurements paid off:

The Kenda 270 that is currently mounted is a 4.50 x 18 with 121mm (4.76in) width and 27in diameter on the 2.50 x 18 rim @ 32PSI tire pressure. Clearances are as follows:

• tire to modified exhaust collector: 13mm (1/2in)
• tire to swingarm: 7mm (just over 1/4in)
• tire to Ohlins: 4mm (just over 1/8in)

I have another rear drive, a 33:11 (3.0) in the works that should reduce rpm by another 7%. That is in pieces with Bruno, who will refurbish it to as-new condition. Try-out -> probably next year.

Meanwhile I installed the new alternator stator and rotor (both parts from Rick Jones) to run that combination this season. I have decided to swap over the entire charging system once a year and run them alternatively and keep the other one as a backup.

I have bought the (ridiculously) hi-viz roadcrafter tank panniers (8l each side) to shift weight (especially spare parts) from the rear to the front and for better accessibility. They are really yellow!

I discussed my Ohlins shock with a local guy, especially the fact that I needed 34mm pre-load without luggage and nearly maxed-out the pre-load at 45mm with load. We established that Kyle USA (although they had all the data) did not set it up for me, can you believe that? It has a 70kg/mm spring installed (which is stock at delivery) whereas I should have had a 95kg/mm. John Sharrard from Accelerated Technologies in GTA swapped the spring (charged me only $50 for the spring and took mine as a trade-in) and then lengthened the shock by 3mm. He noticed that the oil was filthy and dirty! WTF? Did that Kyle guy do anything? NOPE! So I spent another $150 on setting up the Ohlins. Am a happy camper now.

Nuts 'n bolts: I thought I'd use high strength plain finish (black) bolts and stainless where it doesn't count, but they all rust badly on the surface. Even the stainless type A2. Only the A4 stainless is holding up. Doesn't look good, hurts my eyes. So, I put another set of zinc/yellow zinc plated screws, washer and lockwashers together and will install that at rear subframe, the entire front end and the covers.

The fork gaitors were shot when I put them on, they still are. I have original replacements and will put them on before the season.

Will also put the marine type ignition switch in that I bought. Three positions: OFF, IGNITION ON, LIGHT ON

I have bought a new stainless steel brakeline locally, C$43 shipped. It has two banjos (45deg at the caliper, 90deg at the m/c) and goes straight from the caliper to the master cylinder (37.5"), nothing inbetween. See how that works.

The 1in rise and 1in back handlebar riser I had was not really nice, so I had my machinist play around with his machines:

It was necessary to extend the shift lever because getting the boot between the sidestand and the shiftlever was too tight. The springs are stock size, but from an aftermarket supplier.

It wasn't cheaper than buying, but I enjoyed being part of the making.

Season 2009 pictures

• 1990 BMW New Zealand R80GS Frame, legally registered in Ontario, Canada
• 985cc rebuilt engine with '77 R100S pistons+barrels (A-bore), 1980 R100CS big valve dual-plugged heads, 1983 R80RT bottom end (approx CR 9.7 and 70hp)
  Edited 09-Nov-2009: 11/80 R100CS engine, US specs, unknown mileage, refurb'ed big valve heads (km 0), dual-plugged with 12mm second plug (km 0), new rings (at km 16864)
  Edited 10-Nov-2009: oilsump extension (1l DIY) with integrated oil temperature sensor, oilcooler (without thermostat, installation instructions here: http://www.airheads.org/content/view/218/98
• Overhauled 40mm Bings, SLS system removed, jetted with 160 main jets, 2.66 needle jets (new needles) and 45 idle, 3rd notch (initial setting)
• Low mileage stainless steel R100R exhaust system, "de-chromed" and weight relieved, seems to work very well with the rest of the engine
• running single plug points ignition (points-in-beancan) with Dyna green dualcoil (3Ohm) and Dyna Booster DBR-1
  OMEGA Electronic Ignition with two dual tower Dynatek 2.2Ohm (grey) ignition coils (backup: points-in-beancan ignition to go with the gray Dynatek dualcoil)
• remanufactured 280W altermator stator and new rotor (Rick Jones) (backup: known good spares)
• 1982 G/S gearbox, completely rebuilt and modified with a complete set of late design 17.5 Helical gears, mod'ed with a long 5th (HPN)
• Choice of three different 4-lug final drives: 37/11 (3.36) (complete rebuilt), 32/10 (3.2) (original) or 33/11 (3.0) (complete rebuilt)
• Monolever swingarm with 1 1/4 in extension, new U-joint on driveshaft
• front EXCEL tube-type rim 21x1.85, super-laced to a refurbished, low mileage 1993 GS front hub with extrastrong stainless steel spokes/nipples (Woody's Wheelworks)
• rear BMW tubeless rim 18in (X-lace stock R100R front), super-laced to a refurished, low mileage 1993 GS rear hub with extrastrong stainless steel spokes/nipples (Woody's Wheelworks)
• Stock 1989 GS Marcocchi 40mm forks with RaceTech Gold Valve
• CC Products fork brace from SJBMW
• New Ohlins Rear Shock, 95kg/mm spring set up for 220lbs and 1 1/4 in swingarm extension
• Brake modification to a 4-piston Brembo caliper (1999 BMW K1200S) with 13mm m/c and SS brakeline
• Large single beam 7" Clearplastic Chrome Headlight with Xenon HID conversion (triple H4 light output)
  Added Nov 2009: two 20W ATV driving lights for better visibility
• Trailtech Vapor Motorcycle computer with digital voltmeter
• BMW Speedster windscreen
• Hyperlite Flashing Brake Light
  Added Nov 2009: Run-n-Lites Lite Buddies (TM) running lights
• original GS Krauser luggage racks for equal size bags
• Corbin Gunfighter with beadrider

Not a Christmas tree yet, but not far from it, eh!

Much better!

Next up: doing something about the increasing oil consumption!
Before I put the engine together in early 2008, I measured the 1977 R100S pistons and barrels: they were barely in spec for both, taper and ovality, even after honing: "The taper on the barrels is more than 0.1mm with only a maximum 0.08mm allowed. Ovality is most certainly more than allowed. The ring end gaps will be just about in spec.". I expected to get no more than 25,000km out of that set.

I made it to about 17k (2 full seasons) when the oil consumption passed 0.7ltr and it was time to re-assess. I have the original barrels of the Nov 1980 built R100CS engine. Only problem is, it has some imperfections in the Nikasil liner. I re-assessed the barrels and decided to use them this time around. What can happen!

Checked prices for piston ring sets at BMW (they are Federal Mogul/Goetze) and wasn't impressed. There are alternatives however: Hastings and Grant. Didn't know about Grant when I started, so I approached Hastings. Their sets were inexpensive but, the oil ring was chromolly which isn't recommend for use with Nikasil barrels, both are hard materials, so chromolly would scratch the Nikasil barrels. So I searched the Hastings catalogs for suitable cast iron rings and this is what I selected for my "C" barrels:

Ring No.	BMW stock shape	Hastings equivalent	Notes
#1			Type 032 Barrel Face 3.71" dia. 0.675" width 0.168" wall part #35896 Material: #1116 cast iron
#2			Type 126 Rev Torsional Taper Face 3.71" dia. 0.775" width 0.169" wall part #29900 Material: #1116 cast iron
#3			Type 507 Cast Iron Oil 3.7175" dia. 1.86" width 0.157" wall part #31635 Material: #1116 cast iron

All six indivdual rings together were less than $50 delivered CONUS. All of them were slightly oversized and I set the end gap to the minimum as per BMW specification: 0.4mm for top and middle ring, 0.25mm for the bottom oil ring. Installed them completely dry in a degreased barrel. For the oil ring to fit, the width and depth of the piston grove had to be slightly increased.
Run-in started with 1min @ 3000rpm and then cool down, followed by 50km hard riding on the road, constantly opening and closing the throttle full in all gears, but mainly first to third gear. Later that day, I went for a leasurely 3hr ride (Nov 8, 18degC). Bike was feeling great, no blue smoke as far as I could tell. I guess that is as far as it goes before the winter.

I also mounted my new DIY oilsump extension (with integrated oil temperature sensor) ansd sump guard. Both sump/engine and tranny guard are home made.

I always wanted an oil sight glass on the tranny. Bought a standard J.C. Winko fluid sight glass in stainless (part #160FREA/B) and had my machinist change the thread to a M18 x 1.5:

• a 1 1/2" oil pressure gauge from your local hydraulic supply, 1/8NPT fitting, 160psi range, 270deg sweep (my preference)
  => $5.50
• a tubing kit with 3ft-4ft of 1/8" nylon tubing and at least a 1/8NPT Male and one 1/8NPT Female fitting (e.g. EQUUS #9801)
  => $9.10
• one adapter fitting M12x1.5 Male to 1/8NPT Female (to fit the original location of the OEM oil pressure switch)
  => $9.40
• one 7/8" hose clamp
  => $3.50
• some scrap aluminum to fabricate a bracket
  => $0

Final product: