Early R1100RS Fuel Tank

[JamesW]

Maybe I'm just getting paranoid (or bored) in my old age but on my very early (06/93 build) R1100RSL have any of you guys experienced or heard about leakage problems occurring with the early plastic fuel tanks?  I watched a Chris Harris video where he talks about the early R1100RS bikes having what is a kind of tank rot issue but he says he's never seen this problem with the RT models.  Of course when my bike was built the RT model wasn't even yet available.

 

If these fuel tank issues are a real possibility is there anything one can do to head off the problem?  I don't and never have put ethanol fuel in the tank if that even matters.

[9Mary7]

IIRC ethanol was the issue so with your fuel history, you shouldn't have have any problem.

[JamesW]

3 hours ago, 9Mary7 said:

IIRC ethanol was the issue so with your fuel history, you shouldn't have have any problem.

 

I certainly hope that's correct.  I've read opinions both ways.  Actually, the bike never had one once of fuel of any kind put in the tank until 2012 when I purchased the bike from the original owner.  When I bought the bike in '12 it had about a pint of the original fuel BMW put in the tank at the time of final acceptance testing (dyno) before it left the factory in Berlin 19 years earlier.  The fuel filter was completely clogged and the fuel pump was frozen.  So I replaced all hoses and thoroughly cleaned the tank and of course installed a new filter and fuel pump.  Before I even started it I removed the transmission and serviced the input shaft splines.  The original owner had a collection of never ridden or even started BMW bikes.  I wish I could run across some eccentric with a collection of original never started airheads that had no clue as to their worth.  Oh, and this guy kept his collection in a dry climate controlled building as well.  Then he put his collection on consignment with the dealer he used to buy these bikes so I never met the owner.  He even kept up with recalls and the like on these bikes.  He had a K75C that I would have liked to have and I kick myself over that one.

 

Now as time has passed I'm becoming paranoid where this motorcycle is concerned for fear something is going fail like say the M93 transmission which is absolutely not repairable with new parts only old mostly crap from websites like something bay and the like.

[9Mary7]

Even with the early trans, you are starting with a basically new bike so meticulous maintenance and responsible riding should get you years of enjoyable service.

I agree on the K75C.........

[EdM]

I've just reacquired my old 94 R1100RS. My brother in law has owned it for the past 11 years and I just took it back in part trade for my K1200GT.  I've noticed the fuel tank has some issues with the paint blistering and I assume it is due to alcohol in the fuel. I am wondering if there is a way to line or coat the inside of the tank to be safe for alcohol blend fuels as they seem to be prolific now and hard to avoid. For now, I've fully drained the tank as I don't plan to ride the bike for a bit, but would like to get it out once in a while in the future and draining the fuel every time would be a major hassle. 

[JamesW]

7 minutes ago, EdM said:

I've just reacquired my old 94 R1100RS. My brother in law has owned it for the past 11 years and I just took it back in part trade for my K1200GT.  I've noticed the fuel tank has some issues with the paint blistering and I assume it is due to alcohol in the fuel. I am wondering if there is a way to line or coat the inside of the tank to be safe for alcohol blend fuels as they seem to be prolific now and hard to avoid. For now, I've fully drained the tank as I don't plan to ride the bike for a bit, but would like to get it out once in a while in the future and draining the fuel every time would be a major hassle. 

 

I have heard that BMW made available to owners of these bikes all metal fuel tanks if they wanted one.  Doubt you could get one today but I guess you never know.  

[9Mary7]

5 hours ago, EdM said:

I assume it is due to alcohol in the fuel

It is actually the water that is absorbed by said alcohol. Been thru it with first generation Multistrada's where the tanks absorb water from the fuel and swell so much that they no longer fit the mounting points on the m/c. Fuel stabilizers will help but not as much as keeping ethanol out of there as much as possible..... and Never storing the bike with Ethanol fuel in it. Some Triumph Tiger models bubbled the paint due to the same problems. The newer plastic tanks are impervious to this issue but paint also won't stick to them so manufacturers went to tank covering panels for the paintwork. 

[JamesW]

I suppose about the only thing you could do to minimize water absorption (phase separation) is to just keep the tank filled completely.  I'm fortunate to have access to non-ethanol but only premium.  I don't think there is any additive that will prevent phase separation.  

 

I'm feeling better about my 30 year old BMW because I'll just continue to do the best I can with maintenance and if the worst happens then I'll deal with it.  I just can't believe that I can't get parts at all for my M93 transmission but I'm just not going to obsess over it and if the worst happens I'll just deal with it.  I don't know how but I just will!

[9Mary7]

13 hours ago, JamesW said:

additive that will prevent phase separation

 Star-Tron  say theirs will prevent it as well as Amsoil also make a product specifically for phase separation.

I used the Star-Tron in my Ducatis...... 

[Lowndes]

James - Just reading the topic following this one about the transmissions with Dirtrider's comments about the M93 vs M97 transmissions.  Knowing you can swap out for a M97 (and be better off) should help your peace of mind.  https://www.bmwsporttouring.com/topic/106040-desperate-need-for-m97-internals-socal/

 

[JamesW]

Hi Lowndes,  Yes the M97 might and probably would be my only option should the M93 act up.  I don't like the idea of having no choice but to go this route as it would mean buying a, most likely, used M97 and who knows how that would work out.  Would be great if one could buy a new M97 but no can do.  Used to be you could buy replacement parts for your BMW but I think those days are kind of becoming history if your bike exceeds 10 years of age.  Even getting dealer maintenance on Beemers over 10 years old is becoming more difficult.  Just the way things are now in this throw away society.  I love it...NOT!  IMO, my '93 vintage RSL tops a new RS in every conceivable way imaginable.

[Lowndes]

James!!

 

I like the older ones, too!!  Yes, the parts are a problem sometimes.  FORTUNATELY, the help from people on this forum is and has been amazing.  Not just the help with knowledge and technical expertise but help tracking down and actually getting the needed parts.  Without a board member here that was able to pick up a used Final Drive from the seller 30 miles away from him in Frisco, CA, and then ship the greasy thing to me in Atlanta, the '99 R1100S wouldn't be rolling.

 

The whole saga is here in color and colorful language.  https://www.bmwsporttouring.com/topic/103423-final-drive-leak-at-start/

 

There really are a lot of very nice people out there.

 

 

 

 

[JamesW]

Hi Lowndes, 

Yes, you are right.  Repair parts are out there and should the need arise I will be doing some looking.  I was thinking today that Europe might be a good source.  I think there was many more early oilheads sold new there than here in the states.  Not saying I look forward to the search but persistance often times has its rewards and could even be entertaining.  I will look on the bright side.

 

Interesting FD issue you had and talk about persistence in problem solving.  You know this kind of thing could be viewed as half the fun when it comes to aged motorcycles.  Thanks very much for sharing.  it lifted my spirits.

 

J