Advice required, please on BMW K100RS

Hello everyone,

OK so no one is interested in buying my GS850 (see my other recent
post) but I want to get another bike anyway.

There's a K100RS for sale locally for about £800 (55k miles, recent
service, new battery & tyres, T&T) and I just wondered if there are any
things I should be looking out for when I go and look at it.

The year isn't mentioned in the advert and I haven't spoken to the
seller yet but I'm not very familiar with them anyway. I think I want
an earlier model which, I think, aren't monolever (if that's the right
term?) and would prefer 8v not 16v. Boxer BMXs seem well thought of but
the fours do seem a lot cheaper. Do they still have the legendary BMW
reliability? Are there any particular faults I should look out for. I
think BMW luggage is a plus point but I've got some Givi panniers I'll
probably fit if it hasn't got them.

If anyone has any opinions on them, I'd love to hear them. I've not
owned a BMW before so any advice is welcome.

Sorry if this has all been covered here before but I don't remember
much being discussed on them.

TIA

Mark

 

I'd be interested if it wasn't 200-odd miles away from where I live.
A bit too far for me to travel for another SOB

Dave

 

Fair point, Dave and I wasn't being serious! Being yet another SOB is
part of the reason I've kept it so long.

I guess I can always break it...

Mark

 

http://www.verrill.com/moto/kbikebuyingguide.shtml

I've had 5 8 valve K-RS's and have found all of them to be totally reliable.

A neighbour of mine (who was a mechanical idiot) clocked 237,000 miles on
his before a bump with a car killed it.

Early ones suck a small of oil into the combustion chambers and can cause a
little blue smoking on start, especially if they're been on the side stand,
the changed this on later K's (I think around 86/87 ish) by pegging the
rings. I've found using Mobil 1 reduced this trait a little on early K's.

Early ones also require leaded fuel or LRP, I think this was changed about
86/87.

Early starter clutches can get sticky.

Valve shim adjustment rarely requires adjustment.

Rear drive shaft needs removing for greasing around 45000 miles (or the
shaft gears rust and wear) ... reminder to self .. must do mine this summer.

The only thing I've had go wrong during the ownership of 5 K's is a throttle
position sensor failed on one once, still got me home though.

Servicing is very easy, with simple access to valvegear, air filter, oil
filter, fuel filter.

Rear wheel is easier than a car wheel to remove (cos the K has a built in
jack with the stand)

Rear bevel uses EP90 gear oil although I use Mobil 1 synthetic 80w90 in
mine.

Gearbox uses the same oil as the rear bevel.

Standard plugs are NGK D7EA, although I use D8EA's in mine.

Instruments are prone to misting in cold, damp weather. Having the lights on
exacerbates the problem cos it warms the inside slightly. Speedo "drive" is
an electronic sensor in the rear bevel box, requires cleaning occasionally.

Two of the K-RS's I've had have had ABS and I've found it to be very useful.

Motorworks and Motorbins are great for any bits you may need.

Front end is much improved by fitting "Progressive Suspension" springs and
slightly thicker fork oil.

Rear shock usually sagging by 40,000 miles so a replacement shock is needed.

Batteries are about 35 quid.

I can only quote my experience but I've found them to be reliable and
comfortable.

HTH

 

said...

<lifts leg - farts>

 

<snip>

Thanks for all the useful stuff, Steve. I hadn't realised they didn't
have a belly pan, was that only on the K75S?

I think I'm going to have a look at it and then we'll see.

Regards

Mark

 

The K75S had a belly pan and the K100RS SE (like mine) had them too

 

.... as do the 16V.

 

"BMXs"? Harrumph.

Have a look at this site:

http://www.bmbikes.co.uk/index.htm

 

Ooops!

Thanks for all the advice so far. I'm taking a look tomorrow. It's a
1985 model which I thought was before the 'unleaded' heads but the
owner claims he has the original handbook which states it can be run on
unleaded. He did admit that he uses Valvemaster though, so perhaps he
isn't convinced.

Mark

 

No one has been in touch yet so I suspect it'll be here for a while yet
so let me know if you sort things and are still interested. My comment
was meant to be tongue in cheek not to be rude!

Regards

Mark

 

Great bike. Not at fast as the modern plastic racers, but capable, and
comfortable for pillions as well.

<http://www.ibmwr.org> has lots of technical advice also on K's.

Some K100's may have cracked original front disks, unless they have been
replaced at 55kMi, then.

Centre stands may suffer from corrosion and need replacement.

Check mirrors/front blinkers, they may have been knocked loose and in
need of attention.

New coils and HT leads might keep the reliability up.

ABS may be great, but on an old bike it may be more of a hassle (and
expensive) to repair.

Check that the original tool kit comes with it. Also fine to get the
special tool for unscrewing the oil filter.

Original panniers fit well. Some say never buy one without them, since
good ones may cost a fair amount separately. Check that the pannier keys
match.

 

ISTR BMW saying that you can run unleaded but fill up with LRP on every 4th
fill.

 

If you can find LRP nowadays.

According to the Motorworks cattledog, engines built before October 1985
weren't designed for unleaded, and the simplest way to convert them is to
retrofit an unleaded head (£170 2nd hand).

http://www.motorworks.co.uk/rd/Motorworks 2005 CAT.pdf?PHPSESSID=a6945198bcf97ecb4143846ae5b8b62b

 

lovely for that, they are.

One thing that went wrong with mine was the original fuel filter split
- it was a known problem. They had stamped lettering that caused a
stress-raiser.

....and the connector sometimes needs wiggling/cleaning.

....or blows a seal. Can't remember at what mileage, though.

I only had one '86 8-valver but that's pretty much my experience.

 

Hi and thanks for all the advice, chaps.

Well, I've taken the plunge and bought it. Test ride in the pouring
rain this morning. Can't sort the insurance until Monday so I'll be
collecting it then.

It seemed a bit smoky for a while when started but I think it was as
much condensation as anything, given the cold, wet morning. My wife
pointed out that the exhaust seemed to have a hole which may be where
the silencer heat shield fits as that did seem a bit loose.

Still, it went OK as far as I could tell, no rattles to speak of,
strange injector or fuel pump noises but sounded reasonable.

Brakes seemed OK as did clutch and gear change. I partly expected
fluttering on the front brake lever as warped discs are apparently a
problem but again it seemed OK.

Major down side is only MoT'd until May and I *hate* MoTs!

Once again, thanks for all the help, some of the websites look very
useful and I shall no doubt become a Motorworks customer very soon! I
think I'll wait to replace the head and use Valvemaster in the fuel for
a while.

Thanks again. All the best.

Marl