R90/6 w Windjammer, or 1980 R100RT ?

[nhmaf]

The current economic situation, and the rate at which my wife insists on home renovations may well kill this opportunity for me, but I am currently evaluating the possibility of purchasing one or the other of these (2) bikes as described in the title.  Both are in decent mechanical shape, and in pretty fair cosmetic condition, and neither has been operated for the past couple years.  Both have accurate mileage in the 30K range with all working instruments.  Both have hard panniers.   Neither has had top end work done.  I am considering this as a potential ADDITON (without selling/trading either of my present bikes) and using the "new" bike as the "tug" for attaching a sidecar.

I figured that it would help to solicit input/ideas from everyone, as you may well think of things which I have not - and it could be fune, too. So.............
Which would you choose, and why ?
 

[NC Steve]

Personally, Mike, I'd go for the R90/6. I've long believed the /6 series were some of the best looking of BMW's airhead twins, and they're known for reliability and simplicity as well. I thought very hard about an R90/6 before I found my old R65, but bought the latter due to modern improvements, price & location.

Of course, an '80 R100 is really just a /7, as 1981 was when all the BMW improvements began, like Nikasil cylinders, electronic ignition, etc.

Either would be a fine powerplant for a sidecar rig, but  [smiley=thumbup.gif] [smiley=thumbup.gif] , I give 2 thumbs up the the R90!

[suecanada]

My long in the tooth mechanical genius who died 2 years ago at a good age always said to me that the /6 were the ones he thought of the most. He was a Danish guy who was a dealer for beemers back in Denmark I think way back when we were young.!!

[nhmaf]

Thank you for the input !

I gotta admit, the 90/6 is a very nice looking bike.   The one that I've been considering lately is now also up on ebay - it looks pretty sharp, but as I mentioned with the house projects, I may have to let this one slip away (sob) unless I find a hidden stash of cash someplace that I've forgotten about..  I'd heard that the /7 models frame tubes were thicker or "oval" in cross section and that frame-wise, they were the strongest of the cradle frame designs for side hack use since the switchover to the /5 design after 1970.
But, I think that the torque curve of the 90/6 is slightly meatier in the low end than the 100/7, though the 100/7 might have a couple more peak ponies higher up the scale.

This is a link to the 90/6 in question, I don't happen to have a link for the 1980 RT, but there are some nice photos of the  classy looking /6:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=110291002610&ssPageName=STRK:MEWA:IT&ih=001

[Justin B.]

I've had a '75 R90/6 w/Windjammer III and a '78 R100/7 w/Windjammer SS and liked both of them.  The 90/6 was "well used" when I got it (almost used up...) but was a nice bike when I got it finished and I actually got about 1/2 of my money out of it!    The /7 I bought new and put a little over 40k miles on it and it never gave me any problems except a slight head gasket seep on my way up to AK, I stopped at a gas station in ND, borrowed a torque wrench, and continued on my way...

But, since the /6 and /7 were pretty much the same (heavy flywheel, ATE brakes, etc.) it is probably a toss-up.

How's that for a non-answer?  Maybe I should have been a pol...