R65 Tank Swap

[SamF]

Anyone know if there are any other BMW tanks that would be an (almost) easy swap on an 82 R65?  My partner in crime is not partial to the angular nature of the tank but likes the look of some older tanks so we are wondering about a switcheroo.

Can it b done easily or are we looking at major commitment to make it happen?

[Rob Valdez 79 R65]

I think the G/S, GS, and possibly the ST tanks all mount the same way as ours, which is a wire bale around the backbone of the main frame.

All BMW tanks mount the same at the front after 1970, I believe.
The rear could be modified to accept the different mounting of the other bikes.

The biggest issue is, the R65 tank is longer than most of the other tanks, so I think all swaps will leave you with a bit of a gap between the rear of the tank and the front of the seat.

[SamF]

Thanks Rob.  I guess some measurements are in order.  A new seat is also possible - we may be talking serious makeover here.  I do like the bike seen here:

http:// http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1288564120

Is it sacrilege to mod a beemer like this?  I guess I am feeling a bit less guilty as the bike started as an LS but no longer has the fairing so it is less than pristine to begin with . . .

[steven m]

I think the larger more traditional looking tank from the monoshock R65-R100 will fit on an R65.  Same uneven cavity to allow room for electronics along the backbone and same mounting system.  The need for that extra space on the right side of the frame makes most earlier tanks incompatible.  Modifying an earlier tank would be a major effort.

I believe the main frame of the monoshock R65-R100 has the same dimensions as our twin shock R65's, modified to handle the monoshock.  I could be wrong but it's worth investigating.  

Steve

[Rob Valdez 79 R65]

I think the larger more traditional looking tank from the monoshock R65-R100 will fit on an R65.  Same uneven cavity to allow room for electronics along the backbone and same mounting system.  The need for that extra space on the right side of the frame makes most earlier tanks incompatible.  Modifying an earlier tank would be a major effort.

I believe the main frame of the monoshock R65-R100 has the same dimensions as our twin shock R65's, modified to handle the monoshock.  I could be wrong but it's worth investigating.  

Steve

Until you look at the fiche...
This is for a 1986 R80 (under-tank space might be good, but you would still need to modify the rear mount and consider the seat)
http://www.realoem.com/bmw/showparts.do?model=0463&mospid=51802&btnr=16_0239&hg=16&fg=03

[steven m]

Hmmm.  So the monoshock bikes have a tank that is bolted down instead of our, uh, strap?  Check out this beat up tank from a monoshock bike on ebay that the seller is representing as a custom modification:

http://cgi.ebay.com/ebaymotors/BMW-R90S-Custom-Gas-fuel-tank-fits-R80-R100RS-monoshock-_W0QQcmdZViewItemQQhashZitem41447756f5QQitemZ280321545973QQptZMotorcyclesQ5fPartsQ5fAccessories#ht_733wt_1167

item # 280321545973
Steve

[Semper Gumby]

<snip>Is it sacrilege to mod a beemer like this?  I guess I am feeling a bit less guilty as the bike started as an LS but no longer has the fairing so it is less than pristine to begin with . . .

Nope -- Have at it and remember to post pictures.  There are some really nice Cafe bikes here because of welders/fabers with real talent (unlike me who has only persistance to my credit).  

[scotty_b]

R 90 tank I put on my 78 R 65. I restore and customize cars for a living so it wasn't a big deal for me but for some it will require some fab work. Front mount needs to be narrowed, cut off and moved and a new rear mount needs to be made. NONE of the original electronics will fit under the larger tank, so it all needs to be relocated. You can see I mounted my coils on the frame near the foot pegs. Thias also required cutting down the kickstart. It will still kickstart, the pedal is just a bit narrower