Boxerworks.com

Greetıngs-
I moved to central Turkey about 9 months ago. I sold my R90S of 23 years about a year prıor to movıng here from the US.
I am now ready to get back on a BMW (all that are around here are 125cc Chınese scooters and bıkes). Because of the taxes and petrol prıces the most logıcal and reasonably prıced bıke ıs the R80RT. I plan to tour around Turkey when tıme permıts. Thıs is a beautıful country and begs to be explored.
My questıon ıs: Can anyone out there gıve some advıse on thıs bıke, parts/spares avaılablıty, problems to look for? Because I am about an 18 hour drıve/rıde from Istanbul. Everythıng usually comes from there by bus. I have to be aware of the logıstıcs. I have a faırly good workıng knowlege of mechanıcs as I wıll be doıng most of the wrenchıng myself.
Also would lıke to hear ıf dual-pluggıng ıs worth the effort. I had ıt done on the R90S and really lıked the results. I don't seem to get any for certaın answer on the varıous websıtes and the cost and avaılabılty ıs an ıssue. When I make a trıp back to the states ın the near future, I'll load up on fılters, brake pads, plugs, and such. Any advıse would be apprecıated.
Cheers-
Harry

I'll assume the bike is a mid 80s R80RT – and I'd not even consider dual plugging.
By then, the factory had sorted out the no-lead / high-compression / combustion issues
which made the modification an attractive choice for earlier models.

Thanks for the quick reply(s). The fuel here ıs fine as far as quality. The pump fuel ıs the 95 & 97 octane stuff. The problem is it's God awful expensıve! One liter ıs 4.23TL (Turkısh Lıra), whıch is (wıth conversion) around 12 dollars a gallon. I was more interested in the performance bump that dual plugging would offer/ıncreased economy vs. fuel quality.
Also thanks for the advıse on parts. As far as the pıctures. Turkey ıs lıke a miniture US. It has everythıng from beaches to mountaıns, rain forests to deserts. The average tourist only goes to western side (Istanbul and south) areas. There ıs so much more wıth far less tourısts. Just Google/Images and punch ın Turkey, ıt's all there!
Cheers-
Harry

1980 to 84ish airheads had poor valve seats that where supposed to be the answer to unleaded gasoline. It turned out that they where worse than the 1970s. In 1985 they changed the valve seat material and the problem went away. R80s where less prone to problems as they ran a bit cooler and had smaller valves than R100s. If buying an early 80s bike ask he heads have ever been rebuilt, and by whom,as replacing valve seats on an airhead is a bit tricky. A dropped valve seat makes a VERY nasty mess.

In 1985 BMW decided that the circlip on the output shaft of the trans was no longer needed. More here: http://www.largiader.com/articles/circlip/ Some bikes have never had a problem and are still unclipped. Who knows why, but it must be asked if the gearbox has ever been apart. If the bike has over 100,000 kms on it it is time for a re-bearing of the trans soon anyway, and the cost of having a circlip added is not that great compared to what may go wrong.

In North America we only got R80s with 8.2 to 1 compresion and 50hp. In Europe 9.2 comp 55hp bikes where available but I don't know in what models or what countries. If you find an 8.2 bike, Motobins sells the 9.2 pistons for something like 75 quid each. That is the cheapest and easyist 10% power boost to get.

Dual plugging on the early machines was primarily a means to prevent detonation
in the big-valve high-compression engines that were designed for (leaded) high-octane gasoline
at a time when this fuel was being phased out of production,
and the high-octane lead-free gas that later came to market –
just wasn't quite enough to run the old engines well.
De-tuning the engine's ignition or using base gaskets to reduce CR were cheaper means to that same end.
Dual-plugging was a popular choice none the less, and if the system was installed and set-up correctly,
(limited) performance gains could certainly be realized.

In your shoes, I would be hoping for the typical 8.2:1 as opposed to the more rare 9.5:1 CR.
Given the outrageous cost per liter, the slight performance loss of lower compression
might be more than compensated by the lesser cost of a lower octane fuel.
By 1985, BMW had done their homework and were marketing an R80 engine
that performed very well with the lower CR and available pump gas.

Dual plug or high-CR conversion ? Save your money to fill the tank !

Also, if you are looking at a Mono, put the bike on the centre stand and check the rear wheel for axial play. There should be none. Early signs of bearing wear are axial play that can be felt when cold and then goes away when hot. The bike can be ridden for some time yet (perhaps Dougie will chime in) but if there is any play when the drive is hot it needs to be attended to now. Some bikes go forever without the drive being opened, others don't make 100,000 kms.

Dual plugs are only one part of an upgrade package that includes high compresion a modified advance curve and tweaking the carb jetting. When done as a package there is an improvment in power and fuel economy and the ability to run on a lower grade of gas.

Garnet wrote:Also, if you are looking at a Mono, put the bike on the centre stand and check the rear wheel for axial play. There should be none. Early signs of bearing wear are axial play that can be felt when cold and then goes away when hot. The bike can be ridden for some time yet (perhaps Dougie will chime in) but if there is any play when the drive is hot it needs to be attended to now. Some bikes go forever without the drive being opened, others don't make 100,000 kms.

You are pretty much right on about the rear bevel drive.
When I could feel noticeable play when hot after a long ride, I decided to replace/rebuild. It turned out there was also quite excessive backlash between the crown/pinion gears.