Tuesday, February 23, 2010, 04:07 AM ( 14108 views ) - BMW Cafe Racer - Posted by Administrator
Thanks and a tip of the hat to BMWScotter who got me to dig up this post... I guess it's a response I sent to the airheads list. Lots of good ideas here on building a tasteful (and quick) BMW cafe bike.




First, as far as a simple airbox replacement plate, it's a very easy thing
to make. Start with a piece of cardboard and learn where it needs to bend,
then trim it down. Then make the same thing in metal. I made a cool one
for my R60/5 café bike, back when I was running a starter cover, out of an old
WA license plate. It's about the right width, and it gives you some nice
embossed rigidity plus the choice of a nice letter- I had one with 'X',
but I don't seem to have a picture of it.



(you're actually looking at it here, barely, dark triangle between the petcock and side cover, just a bent piece of tin, in this case a license plate, although you can't even really see it. Imagine you're seeing a bent piece of license plate covering the back of the starter cavity, since the airbox is now gone.)



A 'real' racer runs no starter, of course, if that matters. I gather
you're looking omitting at the airbox cover because it looks good, which it does.

But café racers are all about 'feeling' cool and fast, who gives a damn if
you're pegging any more mph on the speedo?

This is why riding position, bars seat and pegs, are so critical to your
experience. I love my café bike because it can literally thrill me as much
as I can stand it at only 45mph. Compare that with a modern sport bike
which can do 100mph effortlessly and you see exactly the reason for a café bike.

It is not about being fast. It is about feeling fast. And it looks fast
and it turns heads. It's fun!



So I have a very different opinion, especially from Danny, who said:


>I vote stock.

Disagree, unless it already is and you like it. There are enough mutt /5's
around that its worth it to either really restore it correctly or modify
it with a vision.


>My philosophy is, if you're going to café something, it ought to be
something that COULD be fast in addition to just looking fast, and that
WAS fast, or at least potentially so, back in the day.


My R60/5 will outrun most R100's, and many oilheads. Not a stock engine,
no, but still only 600cc. For street purposes you can make an airhead very
fast, if you don't mind losing gas mileage.



>(Plus I think most airhead cafes look kinda goofy -- Jon-Lars' Redbike
>excepted, bigtime.)


Here I will agree 100%!!! And I'll except mine too, frankly. I'm biased,
but I'm right:

[/url]

See, I love great airhead café bikes. But I hate ugly ones. I've looked at
a LOT of pictures of them and I'd offer these rules:



Don't mix /5 with /7 era parts, except carefully. I know, I know. That's
half the fun. But realize that the instrument cluster is a really defining
part of the bike, and it makes sense to match that visually to the seat
and tank. Personally, I could never get used to angular /7 covers with a round
/5 tank. I can ignore dual disks though, no problem.

Don't get excited just because you've switched to lower bars and stripped off the RT fairing. Good start. Look around.

Don't overdo the pinstriping. Follow real BMW patterns as much as
possible- there's a right way the lines go over fenders, tanks, and seats. If you make something up, it will look bogus.


Don't use non-BMW colors.There are a lot of good colors to use, if you
want Italian red, why not match an R25 fire bike? If you really want a wider
range, look at BMW car colors, which are where most modern BMW bike colors
come from. Orient Blue is a great deep purple-blue, for instance.

Be really aware that many café seats are really associated with certain
bikes or models, like the John Player Norton. That said, look around and
you'll see that there are some really cool vintage seat repros around for
not a lot of money, including some cool vintage jap stuff. And that said,
realize what a café seat is, and look at its precursors in the Italian
racing 'salami seats'. I personally don't like bobber seats on a BMW at
all, but that's just me.

OK, so enough NO's, let me say something positive here. One of the great
things you can do with a café bike is frankly adopt a full gonzo forward
riding positions. Run clubman bars, to get them down where clipons would
be. (running clipons would mean replacing the headlight brackets)

I mean it. If you have not ridden an airhead with bars this low, try it
first before you comment. It works, I rode mine 5 hours effortlessly to
the Nationals.




The great secret of course is a tank bag which is primarily a pad, and
should be stuffed and adjusted for comfort. Then you're basically lying on
the thing, with your arms outstretched and feet back on the rear pegs.
Just like a normal riding position, you can move your weight to your hands and
feet at will. It's the closest thing to flying.

And this is the big difference. Doubly so if the front end is lowered.

Oh, and get yourself some nice bar-end mirrors, and learn how to adjust
them. Don't settle for stuff that you can't get to work. It's cool in city
riding to be able to flip up the mirrors to squeeze between cars to get to
your turning lane. Gives you nice wide mirrors that fold up for parking.



As far as power, you want some. You want basically a rowdy hot rod, and
the best way to do that is either run stock and shut up, or to install Mikuni
round slide carbs, which you buy pre-jetted from Sudco or Rocky Point for
maybe $300. These give instant kick-your-pants acceleration, great overall
performance, and maybe a third loss in gas mileage. (This too can be
worked, but that's another story) Keep your stock carbs in a box on the shelf in case you 'come to your senses' later.

Another good modification is replacing the heavy stock exhaust pipes with
aftermarket 2-into-1's. They also will make the bike almost as loud as a
Harley, not as loud. Close. BMW folks don't especially like it, but this
is café stuff, sorry. Hey, it's not straight pipes.

Beyond this are other mods which are either debatable (but maybe look
good, like replacing stock airbox setup) or which are a lot more involved, like
a cam swap, or lowering, or medium size, like a lightened flywheel. The
thing is, if you're going that far in you want to be doing it altogether as a
matching package, not upgrading as you go. That's actual race stuff, and
you can do that. For now go with street performance as above and otherwise
keep it simple.

There are a number of upgrades in the form of disk brakes and fork braces
that are very worth doing and which are a good choice for any café bike.


But I think the very first thing is to change the riding position, and
then build the bike to follow. Find out if you really want this full forward
position- it's cool, try it. You can also flip clubman bars upward for a
more normal position, too. The stock motor will give you plenty to play
with this and discover that you love it, or hate it. Most people aren't
lukewarm about it.

Don't forget the tank bag. Lying on a bare tank sucks. Get even the worst
beatup elefantenboy, and find out why they reign supreme:

http://www.x189player.com/r60cafe/image ... eLeft1.jpg


http://www.x189player.com/r60cafe/image ... eLeft2.jpg


If you don't have the position, it's not a café bike, IMHO. And then I
think those are ugly.

-Paul



PS- here are some more hints: study older models and notice what makes
them
look vintage, details like painting the footpegs to match the frame color
make a huge difference.


PPS-

I mentioned the speedo cluster above - this turns out to be nearly the defining element of an airhead cafe bike. Why? Because this decision affects everything else.

What are you going to run the speedo drive from? If it's a /6 or later speedo, you've got to have a /6 or later wiring harness. If it's a /5 speedo, you'll need a /5 front timing cover, even if you're running a late R100 motor - you need the early cover (the timing cover now, the layer the diode board bolts to, not the front cover) witha place for the mechanical tach/speedo cable to fit into... -and- you're going to need a cam with an early style front bearing surface to match that cover... oh, and your oil pump rotor will need to match that cam too...

It's easy to jsut stay stock, then everything matches. If not... you've got to make sure this particular line of dependencies is connected up, or you'll discover at assembly time that something is wrong. (think I got it right the first time...? hah!)

-P

<Back | 1 | Next> Last>>