The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: peteremc on June 22, 2015, 04:39:11 AM

Title: Interchangeable tanks - which models
Post by: peteremc on June 22, 2015, 04:39:11 AM
Hoping someone maybe able help me with information on what model tanks will fit straight to my 1982 R65LS?

I'm doing a custom restoration and want to fit something with knee dents. I'm sorry if I offend anyone but the original tank on LS is just plain boring.

The main issue is that all the mounts for the electrics are on the right side of the frame and the tank has offset contours underneath to cater for this. I believe that a tank from an R80ST or GS of the early/mid 80's will fit but neither have the real knee dents I'm looking for. Any other suggestions?

Many thanks

Title: Re: Interchangeable tanks - which models
Post by: Tony Smith on June 22, 2015, 07:07:17 PM
Quote
Hoping someone maybe able help me with information on what model tanks will fit straight to my 1982 R65LS?

It has been decades since I did this, I also suspect that the legality was questionable then and probably more so now.

With that caveat in place.......

You have two needs, the first is a tank whose base fits the R65 frame and provides clearance for the electrics on the RHS of the frame spine tube. The second need is a tank that has certain style cues that are appealing to you.

Take a fibreglass mold of the base of the R65 tank and a mold of the upper part of the tank of your choice. Adjust your two molds until they fit each other then lay up a new tank base and tank top in your molds (using petrol proof resin of course).

Release your tank top and base from their respective molds and join them - followed by enough layers of woven roving fiberglass so that the total thickness is at least 6 layers, finish with at least 3 layers of something like Dynel and polystryene, high wax resin (so you can achieve a decent sanded finish.

Your other alternative is the Indians on eBay who make aluminium tanks for BMW, have them graft the top of your choice onto a post 1981 R65 base.
Title: Re: Interchangeable tanks - which models
Post by: peteremc on June 23, 2015, 04:40:51 AM
Thanks Tony.

Although I appreciate you taking the time to make the first suggestion, I would be very wary of this approach for the obvious reasons. I completely understand why it may not be entirely legal!

I like the second option. I've seen their tanks for sale, some of which are a bit on the expensive side, I thought. Anyone know about the quality of the product?

A third option I have seen is to make a template of the shape of the desired knee dents, cut them out and then weld the right side cut out into the left side of the tank and vice versa. Any views on this option out there?
Thanks
Title: Re: Interchangeable tanks - which models
Post by: Tony Smith on June 23, 2015, 04:03:21 PM
Quote
Thanks Tony.

I like the second option. I've seen their tanks for sale, some of which are a bit on the expensive side, I thought. Anyone know about the quality of the product?

Thanks

A motorcycle journalist in a comic I read recently bought one for his Triumph Trident and has been praising the quality/originality etc ever since.
Title: Re: Interchangeable tanks - which models
Post by: jamo on July 01, 2015, 11:54:39 AM
I have read somewhere an rs tank will fit a little shorter but wider holding another half gallon of fuel. I think this has knee cut outs I cannot rember where I saw the info. You could contact Motorworks and ask them. Cheaper and safer than making a tank.