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R100RT restoration project begins

ba-heed

New member
Ok here is my new 1980 R100RT, I have just removed the fairing to see what I am up against. It will not go back I am going for the basic bike. A good gunk and de-grease first right?
I can see that I will need a headlight bucket when all that bracket support comes off, I Imagine any 70's airhead unit will fit.
Those handlebar risers do not look original to me ( this is my first BMW so a lot of this is guess-work ) any advice will be greatly appreciated.
The Carbs are leaking I think from the bowl gaskets but maybe the overflows? I should get rebuild kits or ship them to Bing?
The engine has 85K I will change all fluids right through the drive train. I see some oil stains around the cylinder bases, I don't know how alarming that is.( yet )
I am getting a good steady blow by draft from the dipstick hole when the engine is running , again I don't know how much of a problem this is, don't know what the crankcase compression should be on these engines, my research is just beginning. Engine sounds good and pulls well, no smoke.
What about that Fuel tank? The paint is really rough , the bike was originally that metallic red that they came in. Anyway I started to sand a little paint away in the really rough spots and I have come up with this repair, A magnet sticks to it, so what is it? a weld repair? I am tempted to give the tank to the sand blaster now and see if he can blow any holes in it. If I need a new tank must I get one from a R100RT? or will a range of models fit ? this bike is 1980.
I have the Haynes manual and think I will get the Clymer also as I hear it is slightly better, good to cross reference anyway.
My new project has me captivated any help or opinions at this stage are really valuable. Thanks and best regards all around Steve
 

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The headlight bucket you have now is just fine. Will simply need alternate mounting parts, i.e. "ears" that fit over forks.
 
R100rt

Thanks Kent, for some reason I thought that odd shaped headlight bucket was particular to the fairing assembly. I have the "ears" I will re-think now and look closer at the light. I have a bunch of wiring now i do not need , clock , voltmeter , Thanks Mate , all the best Steve
 

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R100rt

Hey Kent, look at that handlebar mount and tell me what you think , that is some kind of "set back" deal am I right?
 
yes, looks to be a set of aftermarket setbacks.
if your repair that you noted is on a seam, then yeah, it would be a seam repair. does it look different than the rest of the tank's work?
It's the RS/RT tank, 6.3 gallon, but any 100 models might have used it. however, i believe that once the bar mounted m/c came along (late 80's?), the backtube shape might have changed. someone else knows better on that one.
buy the Bing repair kit, and their carb book, do that job yourself.
dipstick has metal crush rings. get new ones. be sure it's screwed in "snugly" (but don't get crazy on it). http://www.maxbmwmotorcycles.com/fiche/DiagramsMain.aspx?vid=51643&rnd=08102012

have fun!
 
R100 restoration

Thanks Meister, thanks Fish, Good idea on the forward brake reservoir get it out from under the tank.
I attach a shot of the tank repair I am going to get it sandblasted to see just what I have got here. I don't need such a big tank, may see if I can pick up an R100 tank from the seventies, I would like to know for sure which ones will fit , hopefully a tank guru will come forward .
Bing re-build kits it is then, plus the book.
The fact that you say there is ( or should be ) a crush washer on the dipstick says to me that there should be some crankcase pressure. my concern is the breeze I feel from the hole when the dipstick is out and the engine is running.
Those stains on the cylinder base are they a gasket failing? I will check the cylinder head torque , I guess there are long bolts that go right through.
Thanks again
Steve
 

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The fact that you say there is ( or should be ) a crush washer on the dipstick says to me that there should be some crankcase pressure. my concern is the breeze I feel from the hole when the dipstick is out and the engine is running.

You're going to feel a "breeze" even on a good running engine. That breeze is created by the piston as they head for BDC. Normally, the pressure is relieved by the engine breather system which dumps excess pressure and oil mist into the carbs. But with the dipstick out, the path of least resistance is out the fill hole. So, I wouldn't necessarily put much weight into that. The only way you'll know for sure is by doing a compression check and best of all a leakdown test. That will tell you where the air is escaping and how much.
 
That's funny. l thought you meant there was air blowing out of the oil fill port with the dpstick in the hole!

so what happens when you run the bike with the dipstick in place- as intended? Engines are basically just big air pumps. normally the air goes out the exhaust. letting it blow out the oil fill hole is not how we generaly ride these things.
 
Somewhere in the mid 1980's, most of the electrical components were relocated out of the headlight shell and placed on the frame backbone. The fuel tank fit-up dimensions are pretty much the same on all the sculpted tanks, but the underside is shaped differently to allow for the change. The first model with this type of tank would be the 1974 R90S. Earlier tanks (/5 and /6) are shorter and while one would fit on your bike, there would be a gap between the tank and the seat. The repaired area of your tank is a common wound from the inner fairing parts coming in contact with the tank.

Regarding head nut torque; don't over-do it. The experts recommend 25ft/lb at the most. The cylinder and head are assembled on long studs that are threaded right in to the motor casting. There is a propensity for the aluminum to fatigue and the studs to pull loose from the block. I experienced that issue on a 1988 R100RS that I currently own.
 
Bing re-build kits it is then, plus the book.

I've purchased both the Bing and BMW re-build kits, and believe it or not, the BWM re-build kit was cheaper than the Bing. But, that was several years ago, so I would price them both. Just my $0.02.
 
r100rt restoration

Thanks Jeff I will check the prices. Thanks for the Tank info James that all makes sense. Plus I will take it easy with the torque wrench, did you have to re-weld the block on your '88 or can you fit heli-coils in that situation?
 
Tank repair exposed

I had the fuel tank sandblasted today and I think the repair would be more costly than a good used tank so I am shopping.
 

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