I had a fairly heavy highside on track and the 1098 flipped landing tail first upside down before the rest of the bike followed. Whilst I have a lot of work to fix the thing, one issue is that the subframe is slightly bent. Now I believe I will be able to straighten it and via measurements etc check that it is fairly square. My question is does it need to be laser precision straight or or just straight as outlined above provided it's structural integrity is intact? I can't see why it needs to be "perfect" but thought I would check with those that know better than I. All advice appreciated.
The sub frame needs to support your weight and attach the rear bodywork to. If you are happy the sub frame does that, IMO, you are good to go. Andy
Bob, a word of caution. I got rear ended by a BMW 530 on my 748, the subframe and rear wheel took a 30mph impact from behind whilst the bike was stationary and fully upright. On first inspection the damage was limited to the rear wheel and subframe which was bent upwards maybe 5 degrees, plus the pillion pegs were splayed outwards on both sides. However, on closer inspection the subframe had acted as a substantial lever on the mounting points to the main frame. It stretched the lower two mounting lugs oval and on very close inspection has very slightly distorted the entire upper rear part of the frame where the fuel tank bolt locates. Other clues I would suggest you look for include if there is any evidence of movement of the airbox relative to the frame, cracks around the airbox fastening points, the subframe mounts are undamaged and that the vertical tubes at the back of the main frame are still true and straight. Mine will eventually take a trip as an engine fitted rolling chassis to Motoliner for alignment checks and maybe repairs, gut feeling is it is unrepairable and the frame is scrap. Discussing it with them the jig is not really designed for repairing distortion that has occurred at the rear of the frame or in the way mine was 'opened up'. Sounds like your has been closed in. Fingers crossed yours is all straight and true.
If it's for track day, then as said, as long as not weakened and no fractures (steel subframe?) then as long as seat faring fits and you can screw on exhaust support ok then I would be happy. Fitting the seat fairing closing panel that goes between the two might be a different matter though, as can be painfully long-winded even as std.
Plenty of used subframes on ebay, going for not much money, or message @DRR117 he may well still have the one from my 1198SP, which is pretty much as new.
I've seen people straighten subframes by eye with a long lever on TD's, as long as it's not cracked and it's a track bike it'll be fine.
