'83 R100RT going naked...

[prairieguy]

As part of the "nudification" of the RT, I'm removing the oil cooler. I have a part number for a non-cooled oil filter cover - 11 42 1 263 345. But, no one has been able to tell me if this is the right cover for my purposes. I already have ordered the correct pipe that goes inside.
I also have a question about wrapping the wiring harness. The previous owner(s) used an enthusiastic amount of electrical tape, and I didn't like the stiffness of the harness as I turned the bars. I've removed a great deal of it to clean things up and check the condition of the wiring, and now I'd like to wrap it up properly. I'm aware that there are different options for automotive purposes, but I don't think they're good for a bike. The harness is flexed quite a bit at the steering junction, so I really want the right protection on my harness.

 

[20774]

I went to RealOEM and selected the '83 R100RT. This is the page they show for the oil filter setup. I think you're part number is correct. This is the same cover that is on my non-cooler '78 R100/7...I don't think there is substantial different in these engines regarding the oil filter when the oil cooler is not used.

http://www.realoem.com/bmw/enUS/showparts?id=0449-USA-03-1983-2474-BMW-R_100_RT&diagId=11_1721

 

[bob_m]

My son now owns an 84 R100 standard (I cringe calling it naked) This is basically stock and came with no oil cooler. It has never had overheating problems and changing the oil is simple and quick.

 

[brewmeister]

You will need to change the pipe inside the oil filter compartment to a different length or the cover will not seat the filter properly. Good luck .

 

[lkchris]

You will need to change the pipe inside the oil filter compartment to a different length or the cover will not seat the filter properly. Good luck .

And use a different oil filter!

 

[lkchris]

If you've been keeping up with Oak and subsequent Airhead engine events, you'll know that the big-valve heads used on most of the R100s through 1984 proved subject to warping as the valve sizes left too little material remaining. When R100s returned after the "last edition" attempt, they didn't have valves that big. Removing the oil cooler is a bad idea. Wow, would you take it off an R100GS?

The OE oil cooler thermostat on these bikes usually only opens during really high speed runs--these are the times the motor works the hardest, burns the most fuel, and generates the most heat. One wonders at the difference in aerodynamics of RT fairing versus naked ... could be the aero is worse and therefore the engine works even harder at high speeds.

I'm always sad to hear of another RS or RT going naked. It just means, of course, couldn't afford to repair the fairing crash damage in most cases.

 

[barryg]

In a past life I did alot of BMW airhead twin heads. Enough to see patterns. I really didn't see warped valve seats or valves in the '77-'80 big valve models. Those heads just worn out in an even pattern over normal engine life. The '81 thru mid '80's had the problem. This was the advent of the emission models with the air injection systems. I don't know if it was BMW or their venders who were the culprits. All heads, small and large valves, those with and without fairings were subject to the unatural wear and deformation. At the same time some heads came in from those years with normal wear. My thinking was that the quality control at the venders could have been one of the problems or that BMW engineers had missed on the type of valve and seat material needed with the new emission bikes. The air enjected system of air being pumped to the exhaust port obviously created too hot of an area for the head. I think these factors in combination were the culprits. I think BMW''s plan was to phase out the 1000cc twins with the advent of the water cooled k bikes. When the 1000cc bikes returned in the later 80's maybe the engineers had finally found the better formula for valves and valve seat material. I think BMW kinda dropped the ball on their customers on this one.

 

[20774]

The '81 thru mid '80's had the problem. This was the advent of the emission models with the air injection systems. I don't know if it was BMW or their venders who were the culprits. All heads, small and large valves, those with and without fairings were subject to the unatural wear and deformation. At the same time some heads came in from those years with normal wear. My thinking was that the quality control at the venders could have been one of the problems or that BMW engineers had missed on the type of valve and seat material needed with the new emission bikes.

Mostly the problem was that the wrong seat material was used, a material that didn't transfer heat very well. The valves took the brunt of the excess heat. But some bikes in the '81-84 timeframe were somewhat OK or never really exhibited any problems. My Dad's '81 R100RT ran fine for all of his time with the bike...BMW maintained it and never indicated there was a problem. I remember reading something that Oak mentioned that the angles in the seats, or the width of the contact surface, also contributed to the problem. So, I'm thinking that if you had a bad angle grind, you were pretty much toast. However, if the seat angles or certainly the width of that angle that actually contacted the valve was just a little wider than normal (ie, quality control), then the engine could withstand the abuse a bit longer. Certainly a number of variables, including owner treatment of the bike, that could have made the results vary widely.

 

[barryg]

Yes, I forgot the valveseat angle and width. This info was made available to service venders as BMW changed their recommendations over time. I've got some of those, I'll try to post them tomorrow. Service updates I guess.

 

[prairieguy]

My original plan with this bike was to clean it up, do all the maintenance it needed, and put the original fairing back on.
Said fairing never materialized as promised by previous owner...
And then, " hillbilly zen engineering " became apparent, though not as bad as another bike I've read about on this forum. Also, some interesting custom touches that butchered original part$...
I decided to make it into a more standard style bike, (no more butchery), though suited to my taste. The more I tinker with it, the more I love the simplicity of the design. There's an awful lot of elegance in making something easy to work on and still fun and good looking - and that's something I don't want to f**k up!

I'm not a big fan of this mod. I'm thinking older style mounts would be nice.


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[prairieguy]

Hello Guys, I've returned to this project. Garage space has been cleared up, and all other bikes removed (sold). The refreshed goal I have is simply to make it a fairly reliable, short trip bike.
The oil cooler will be staying, and a shorter, brat style seat installed. The rear sub frame has been bobbed.
I would like use a modern lightweight battery, but I have no experience with switching battery types.

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[PAS]

Wire harness tape, Tesa brand is what the OEM was.
https://www.amazon.com/Tesa-Wire-Loom-Harness-Mercedes/dp/B00EH6IZ6Y