Ok, First hiccup has arisen. With the Biposto subframe placed on the bike, I can only slide the tank and seat unit back to the 2nd (middle) adjustment position. The restriction is the plastics behind the seat butt up against the addition spar in the subframe that's not present on a Mono subframe. I can force it to the 3rd potion, but this flexes the plastics behind the seat, and makes the mono rear cowl sit at an upward angle (some might not mind, feels incomplete to me). This make a lot of sense as to why perhaps the Biposto was never adjustable. Anyway, my goal is to create something that operates correctly in Mono and Biposto setup, whilst remaining DIY for most of individuals. Cutting and chopping the subframe is out, as I can't morally be sure that it doesn't compromise safety. I could ultimately draw the subframe in CAD and conduct an FEA test to see what would happen when the manufacturer specified maximum weight is present, have access to a spectrum analysis machine to be able to determine exactly what it is, and the software is clever enough to calculate the thinning wall thickness around the bends, so it should give an accurate result. Then we could cut and shut in CAD and see how that changes things. Phew! this is becoming a rabbit hole. My current thought is to weld a new plate with the 3 position holes approx 10mm higher, this looks like it would clear as the back of the seat plastic isn't parallel to the spar it makes contact with. I will have a think and report back. Have a good day everyone.
Time for an update, since getting a Biposto subframe on, i'll profess, I've just enjoyed riding the bike (albeit cramped as the Biposto fixing is equivalent to the furthest forward and lowest setting on the mono). I "think" I've figured out a way to get adjustability without cutting or welding additional material. They will be a set of machined, bolt on brackets. I'll hopefully get some stress testing done this week, and i'll publish pictures and results. Have a good day everyone
