Motorcycle Write-ups

some are related to the BMW R1100S

by Ben Barkow


More or less general bike topics.

Many debates about air/fuel ratio, closed-loop operation, and related ECU mods. Here is my experience riding around on an R1100S with an A/F meter. Lots of people talk about A/F, but nobody has published on-road results (inertial dyno A/F curves are close to worthless). This report will tell more than you want to know about the Bosch/BMW Motronic 2.4 ECU.

All kinds of tools for "synching" (AKA balancing) carbs and throttle bodies are being sold. Buying two (or three) ordinary, cheap, automotive vacuum gauges and then watching the balance at idle and while on the road "under load" makes the most sense.

After-market mufflers and how to re-pack them with products that work.

Clean your fuel injectors. The cleaners will also provide you with before and after test results. Here's information.

Don't ask me why, but you see voltmeters on bikes and cars from time to time but never ammeters (OK... the reason has to do with money.... surprised?). But a temporary free ammeter hook-up (using your voltmeter) tells you just about everything you might reasonably want to know about your battery and charging system. Read this and say to yourself, "Why didn't I think of that."

Dynamic balancing is essential to prevent vibration and wobbling when parts rotate. Any parts of your bike rotate more than, say, 1000 rpm? Right! So you should do something about dynamic balancing.

Here's my take on bike suspensions, a primer.

Windscreens, bars, seats, pegs, and various things should be adjusted on your bike for good ergonomics. Sometimes easy to do but you need to know the theory or you could make your aches worse.

Newer bikes use the angle method for torquing bolts. I think the old torque-wrench method is better for curbside wrenches. Maybe?

Tired of your stinking old internal combustion engine. Yeah, me too. Thinking of a test ride on high-performance electric motorcycle like the Zero?

A long trip with my congenial wife from Toronto to Los Angeles through fabulous areas in the US west.

Some more or less BMW-specific topics.

The recent BMWs have had a Paralever rear suspenion. I'm sure this has been voted one of the greatest mistakes of 20th century automotive engineering. Anyway, you can reduce the stupidity of the design by installing bronze-bushing bearings to replace the needle bearings. Do it today.

BMW have also been using multi-electrode spark plugs. There are some reasons why that makes sense in a car, but not for bikes. Here's a much better plug idea.

Here are some easy constrution articles.

THIS IS THE SMARTEST AND EASIEST AND BIGGEST PAYOFF mod you can do: add a throttle counterforce spring.

For compelling reasons, it is good to add balance to a multi-cylinder engine, particularly a balanced boxer. Adding some kind of balance pipe between the intake throats makes sense.

Part of good touring ergonomics is a good windscreen. Here's a little text about making windscreens.

 More specific to the R1100S bike:

Would you like to see numeric results for actual, real-life, legitimate, sensible tests of paper, gauze, and sticky-foam air filter media?

BMW, in an effort to goose-up the HP at mega-herz rpm (pretty dumb place to make your HP unless you do nothing but race), they installed an internal baffle to block 85% of the front exhaust cross-over pipe flow. The cross-over is mostly just for decoration! Remove your pipes and drill out the small hole in that cross-over baffle and you'll unleash lots of power below 3500 rpm.


Here are some plans related to the R1100S Corbin seat:

The R1100S has a cowl or cover for the passenger part of the seat. Here I show how you can make a needed parcel carrier.

The Corbin has a dreadful passenger backrest. Here's the way a professional ergonomist would do it right — with pictures.