Sub-frame vertex stabilisation ?

[Soliton]

Imagine you were making a single seat sub-frame for your R1150. No more passengers. The seat pan and side covers will be modified to show off as much of the frame as practical. Essentially the frame will become both structural and decorative.

You have soft panniers for those times you are going for a longer ride and instead of using the full rear muffler you are going to use an abridged after market muffler.

The frame has been modded and is in the last stages of finishing. The weld seams were lightly hand polished with wet and dry and thin filled and re-sanded. They were not ground down.

Would you bother stabilising the frame vertices? I have done the drawings and made up some prototypes, the edges on the inside of the triangle will be lightly curved and each piece will have a 6mm hole to allow me to mount cover plates at a later date. 2 or 3mm mild steel should be sufficient. (about 3/32 to 1/8 " I think)

Doing it before the finishing will add time effort and energy (and a small but reasonable cost). If I do it the frame will probably be bead blasted back to the bare metal and all of the weld seam re-finishing done again. #m abrasion resistant tape will go in the same points that BMW apply it. Pesky but I want the surface finish to last as long as possible

The sort of thing I'm thinking is this. Is this sheer bloody mindedness ?

[riceburner]

Yes

[sweatmark]

Yes I agree with James - some additional rear subframe structure would help balance with forward bike structure, which is dense. If the rear subframe somehow resembled the Telelever A-arm (segment thickness, curvature, % open area) then a chopped bike would look more put together.

I was inspired by your original bike with shortened tail.Have been thinking about R1150R customization options ever since.
Some of the "seat only" shortened customs look awkward, at least with rider aboard. But a simplified machine has appeal, particularly with tail ending just forward of the rear wheel's rear-most (is that a word?) end. There are some examples on Bike EXIF that demonstrate this... I will hunt for links if helpful.

The tail of the R1150R and "head held high" nature of Telelever structure seems to be challenges for optimized design.

[Soliton]

Head held high, that is exceedingly diplomatic.

Curious meerkat is the image that sprang to mind for me and was one of the first things to get "fixed" Centreline of headlight is now aligned with the centreline of the tank.

Decision made, stabilisation is a go, off to buy some 3mm flat bar stock.

Thanks guys.

Rs

Sol.

[Soliton]

Head held high, that is exceedingly diplomatic.

Curious meerkat is the image that sprang to mind for me and was one of the first things to get "fixed" Centreline of headlight is now aligned with the centreline of the tank.

Decision made, stabilisation is a go, off to buy some 3mm flat bar stock.

Thanks guys.

Rs

Sol.

[sweatmark]

Example of "mono posto" perfection:

https://www.bikeexif.com/walt-siegl

Tail extends just past rear wheel centerline. Bike stance is perfectly suited to sporting intent.

[Soliton]

Thanks for the encouragement. The hardest bit is done. The curved sections have been rolled to give the finishing something to stick to. I gather nothing likes thin sharp 90 degree angles. The radius of the roll need to be evened out and blended a tiny bit.

A few final adjustments prior to the welding to get the fit exact and it should be ready to go. I ended up using 3mm flat bar stock

They aren't perfect but I am happy with the result. When they have been welded in, a wee dash of JB weld, some epoxy primer, some high fill primer , 2 x 2K base coats and 3 x 2K high gloss clear coat will conceal most imperfections.



Rs,

Sol.

[riceburner]

Can't wait to see the finished article!