data.3news-bydate.train.rec.motorcycles.105239 Maven / Gradle / Ivy
From: [email protected] (neil.a.kirby)
Subject: Re: Two Beemer Questions (R80GS)
Organization: AT&T
Lines: 75
In article <[email protected]> [email protected] (Erik Asphaug x2773) writes:
>Hello Folks,
>
>I'm very happy with my "new" R80GS. My range is 238 miles on 4.8 gallons...
>that's 50 mpg!! Surprisingly, the bike is a real cruiser. I was expecting
>something rough. She's a sweet backroad honey. And I can go pretty much
>anyplace I'd take my mountain bike. As far as shaft effect, it's more a
>torque effect from the crankshaft in my opinion. Rev it sitting still
>(when the driveshaft is not moving) and the bike twists a bit. Maybe
If the clutch is in, then a large chunk of counter-rotating mass is not
rotating. Hence, at a light, reving makes it twist. Shaft effect is the
rear end rising under power or (the real problem) getting lower to the road
when the throttle is snapped shut (say when you are cornering and the heads
are real close to the road). New GS bikes with the paralever shaft have
almost no shaft effect.
>I don't ride her fast enough to get a shaft effect, but in my opinion
>a little buffeting by wind is of far greater consequence. Okay, here are
>my questions:
>
>1) Any recommendations for a home-made fairing? I'd like to keep the
>wind off my chest, and perhaps my helmet, for comfort at highway speeds
>(70 mph), yet don't want to (a) screw up the stability or (b) block my
>vision too much for trail riding. Anybody have luck with two-piece
>detachible fairings? I'd like to make it myself out of plexiglas.
>2) I run two lights, the standard headlamp plus a sidelamp mounted on the
>crash bar. The illumination's excellent that way, with a full beam coming
>out from the level of the motor (left side); the lamp beam is linear so
>that you get a bright streak of illumination from left to right, and it
>really picks up the periphery (deer lurking, etc.) Combined with the
>headlamp on high you can see like day. But I've heard that BMW alternators
>don't crank out too much. Do I need to shut down the sidelamp when I'm
>puttering around in the dirt at low RPM?
It's a question of how long you spend at low RPM and how much you need the
extra light. At low RPM, 3K and under, they don't charge all that much if
at all. The alternators put out sufficient wattage, it just that you need
to be at 4K RPM to get it.
>3) This is embarassing: I'm having trouble starting the bike first thing
>in the morning. I invariably flood the carbs, then go in and read a section
>of the paper, and then she starts right up. Is this a Zen thing?
Full choke. Open the gas taps. Hit the starter and ever so slightly blip the
throttle. It should fire. Cranking should be done with minimal throttle.
My R100 likes the throttles to be raised just a bit off idle.
It's an EXPERIENCE thing. Like Zen, it's hard to describe. It can be hard
to learn if you aren't paying atttention to the differences between success
and failure. Especially if you get really pissed off and flatten the
battery while trying to get it to run.
If my bike has been sitting for a few weeks, I give it a short while to
start. If it doesn't, I turn it off and wait a few minutes for things to
vaporize in the fuel system and then it lights right off. I've got dual
plugs which make it easier to start.
>4) The Hayne's manual says do not under any circumstances use gasoline
>with alcohol additives... Yeah, right. What do you folks due to keep
>the engine and carbs from being eaten by ethanol and methanol? Any
>particular brands of gas that are best? Additives?
The BIG fix is the Bing carb upgrade kit. It's good for a few MPG and the
parts are alcohol proof. The parts it replaces aren't alcohol proof. As
long as the bike isn't going to sit for long periods of time, gasohol is
nice since it helps keep ping away. If your bike doesn't ping on cheap gas
you ought to raise the compression! (Half a smiley, the BMW twins of the
80s and beyond have lowered compression to keep the EPA happy. Dual plugs
and higher compression give back a big chunk of the lost perfomance).
Neil Kirby DoD #0783 [email protected]
AT&T Bell Labs Columbus OH USA (614) 860-5304
If you think I speak for AT&T you might have more lawyers than sense.