Paging Beemer owners

The point is to know what you're taking on. It's like buying anything
mechanical on eBay - you work out the risks of something not being as it
should be, the costs of putting it right, and bid accordingly. Or at
least I do (and I know you do too). I'd rather know about something, and
then be able to choose to ignore it, than not.

Regards,

Simonm.

 

Well with 23k on it that shouldn't really be an issue.
The rear crank seal isn't difficult to repair in situ IYKH, the gearbox is
another matter.

 

Hog was seen penning the following ode to ... whatever:

Agreed, but you never know.

You still have to take the 'box out, don't you? That's at least a lot
of hassle, so I'd try to get some money knocked off the price.

 

What's special about the spanner?

 

It has little flanges that locate into the fins on the nut. More special
tool than spanner.
www.nithburgcycle.com/bmw/tools.jpg

 

Not for the power.

There is that.

 

We-ell, it's geared so it jut redlines in top, so yes, ISWYM about the
power, but IMHO if they'd just geared it up so it wouldn't pull the
redline in top it would make it a bit more relaxed at speed, and more
economical.

It is a touring bike after all.

Some owners gear them up using a different crownwheel assembly. OK, so
you lose a bit of top-gear driveability, but wtf.

The 800 engine itself is much nicer than the 1000cc ones, IMHO.

 

The Older Gentleman was seen penning the following ode to ... whatever:

AFAIK the usual mod is to fit the crownwheel assembly from the
unfaired one, although that might be a bit too high geared.

That it certainly is.

 

What utter tosh, it's an underpowered shed!

On the subject, BMW are launching an all new 1200cc boxer engine according
to MCN (spit) with a balancer shaft and lots less weight/more power. An
R1200S boxer cup along those lines might tempt me back.

 

Yes, I was looking at the cutaway of that, with all those chains
twirling around inside it, and wondering how long they'd last.....

 

^^^^^^^^^^^^^^

Why? Perfect primary balance (supposedly) - one reason for a flat twin,
shirley? Or are they admitting to something else...

The "less weight/more power" bit sounds nice though.


Regards,

Simonm.

 

The BMW twin engine design has a rocking couple due the the offset
crankpins.

 

I did wince for a moment but the K camchain didn't give problems and the
oilheads have been ok in that respect AFAIK. I guess chains are considered
quieter in these fucked up times.

 

Good point. But it sounds hard to balance that out with yet another
shaft. There ought to be some way of adapting the Harley approach for a
flat twin (he said, struggling to think of a way to have two big ends
180deg apart but on the same lateral axis), or is it just Germanic
pride?

Still sounds like a bit of a dog's...

Regards,

Simonm.

 

Forked conrod, like Harley do.

It does to me too. It sounds like they've enlarged the engine beyond its
intended limits, at 1200cc, (shades of the od boxers) and realised that
the things shudder nastily.

1.2 litres is a bit big for any twin, IMHO. I know some vees go a lot
bigger, but they use rubber mounts etc...

 

I think that would shake itself apart in no time - you'd have to fire
the cylinders alternately. In order to work, you'd have to have the
cranks diametrically opposite, so that you firing strokes coincided.

I thought Harley only get away with it coz it's a V-twin with a
correspondingly odd ignition timing (and they rubber mount, etc.).

The other intersting (nasty) thought is that, even if you balanced out
the gyro twisting force (two contra-rotating masses ought to cancel
out), it'd still want to keep going in a straight line no matter what
you did with the bars or counter-steering. Nasty trade-off: a flywheel
gives you smoothness, but also a tendency to ignore corners.

Regards,

Simonm.

 

Pause and consider the concept of two 600cc pistons flying left together
..
..
..
now right
..
..
..
Ok, you have been flung 20ft from the bike, what now

 

Conside the concept of pistons flying outwards and inwards, together?

 

It would be a bit over-relaxed getting to speed. As it is, the gearing puts
the ratios closer together (and easier to change), which is good as going up
and down the box is the order of the day if progress is to be made. It may
only pull the ton, but it'll do that up hill and down dale even with madam
on the back.

The ratio on the RT is 3.36:1, the naked R80 is 3.20:1, and the R100RS/RT is
3.00:1. If I decided to put up with top-gear sluggishness and fit an R100
ratio, I could get a secondhand bevel box from Motorworks for £240, or a
recon exchange for £225. If this gave me an improvement of, say, 5mpg
average from 35 to 40, I'd save about £150 a year. However, I don't believe
I'd see that much of an improvement, because I'd only be using less fuel
while cruising at a sensible speed. The rest of the time I'd be using more
fuel because I'd be in a lower gear. Of course, if I slung on twin-plugged
heads to up the performance, it might work better - but It would be three
years to break-even, and how much money am I going to throw at this SOB?

Well, that's all right, then.

 

On a single crank-pin, YTC?