I have a project bike which is either a 79 S bike or an RT converted to S. I just took a look at it. What I have is consistent with the pics. The bike is black, though I have thin red and gold pinstripes. The engine front cover is ribbed on the sides. I understand that this was changed with the introduction of the bean can points. And I do mean points, not sensor. The seat cover does not look like mine. The engine badges are generic BMW. The engine top cover and filter is clam shell type. The front brakes are ATE w under tank master cylinder. The rear brake is Brembo hydraulic. The gear change lever is the adjustable type, but that was introduced for '78.
That's about all I picked up on. I'll likely be out of touch this morning, but I would be happy to answer any questions that I can, or at least any questions that can be answered by looking.
I have a couple comments about the bike that this post is about. The bike shows significant neglect, things like the cockeyed turn signal housings. I do have one particular concern. I see quite a bit of rust, for example the rust on the carb tops. This tells me that the bike has spent quite a bit ot time exposed to weather. The paint would also be a give away, but the paint looks relatively glossy, though dusty. Hard to tell. But a bike that has been kept out of the weather will have glossy paint. In particular I would look at the frame paint to see how it's holding up. Also the tank badges appear to be "not yellowed". Another good sign.
That's about all I picked up on. I'll likely be out of touch this morning, but I would be happy to answer any questions that I can, or at least any questions that can be answered by looking.
Were I actively looking for another airhead I would be interested in the bike, but cautious. I would be particularly concerned about the condition of the under the tank master cylinder. I would want the brakes to feel firm and correct. I would be particularly concerned about signs of leaking brake fluid on the frame top tube and surrounding area. This area is seemingly always gunky from brake fluid.
Oh, and the speedo and tach and lights really need to work, or the bike be priced accordingly.
In summary, from the pics, I would make a perhaps WAG that the bike is relatively low mileage but has had a hard time being exposed to the weather.
Oh, and yet another thought. If the owner is cooperative I would really like to see a bit of transmission oil to see if any water is in there. An airhead spending significant time in the rain will often collect water running down the speedometer cable and into the transmission. Seeing the oil is hard to do without draining it, but perhaps the owner would consent to a wire being dipped into the oil and examined.
Also I would want to feel the backlash in the drive line by lifting the rear wheel above the ground and rotating it back and forth. That might give you some insight as to the condition of the rear wheel and transmission splines.
Does the bike run and idle well, carbs synchronized too? I would expect the answer to be no. That certainly wouldn't be a show stopper, but is something to consider, again, what has been the quality of maintenance.
I would certainly have room for that bike at the right price!
Addendum: The transmission is ribbed.
Ken, lusting lightly in OKlahoma