- Joined
- Apr 6, 2005
- Messages
- 1,899
- Age
- 64
- Location
- Out in the sticks of NE SC
- Bike
- R1200 GSA / S1000XR
I have two similar / dissimilar bikes under resto-mod at this time: A 1993 BMW K1100RS and a 1998 Honda ST1100. The BMW and Honda attack the same job from different angles. The BMW is a water-cooled, fuel-injected flat sideways inline four with a single-row timing chain, a catalytic converter and a dry (automotive design) clutch. The suspension is sophisticated with 42mm cartridge style Marzocchi forks and a single sided swingarm. It used to have ABS, but I snatched it off
Honda chose a water-cooled V-4 design with a rubber timing belt, no converter, a bank of four carburetors, a wet clutch, and shaft drive. ABS was optional on the bike. The suspension is more conventional with a 41mm damper rod anti-dive front forks and a conventional steel 2-sided swingarm.
They both ended up with 1100cc’s of overweight motor putting out 100 hp with adequate torque under 2000 rpm (unusual for motorcycles). Both have historically shown that they are capable of 200,000+ miles without cracking the engine case. This was BMW's most robust motor before or since. Honda achieves essentially the same outcome with much less up-to-date technology at about 1/2 the list price of the BMW. What’s funny, is that the Honda is five years NEWER than the BMW.
The fuel injection of the BMW looks downright simple...
Compared to the bank of carburetors on the Honda…
If you want a master’s degree in carburetor rebuilding, this is probably your final exam. Wow. I have never seen so many linkages, springs, shafts, balancing screws, and vacuum hoses in my life. All that is left now is to re-jet the pilots when the replacement parts arrive. I am re-jetting it to Canadian standards as seems to be the consensus thing to do with these.
I have a third rebuild going now of a Volvo 240.
It is interesting the need to change gears mentally between Swedish, German, and Japanese engineering practices.
I just finished reviving an airhead BMW from a 14 year nap for a friend of mine, so throw "old school" BMW on top of these. The airhead BMW's always remind me of the tag line from Hooter's Restaurants - "Delightfully tacky, yet unrefined".
The K bike seems like it was designed by the BMW car people while the old school guys took an extended beer break. They came back good and drunk and designed the R1100 oilhead. Comparing the ST1100 to "old school" Honda builds is equally enlightening. I finished a 1971 Honda SL350 for my brother a few months ago. The increased level of technical sophistication and the obvious designing for longer service life in the new bike is world's above the old twin. With weak top-end oiling, the 350 twins were about done-for between 10-20K miles. But, very few people rode them that much. The smaller cylinder to the right of the clutch is the oil slinger. Where the oil pump in the BMW can spray oil across a good-sized shop, most folks can pee harder than this old Honda pumps oil. Filter? we don't need no stinking filter!
Of course BMW did not add oil filters to the twins either until the 1970 launch of the /5 series. Before that, they had slingers as well - but unlike this easy service on the Honda SL, the BMW required removal of the engine and then the crankshaft - very specialized work for an expert.
This is an interesting hobby we have. A lot of people from a lot of countries have put a lot of thought into how to push our lazy butts down the road in progressively higher style..
Good stuff, Lee. Love it.
