This is the replacement rear gas tank rubber damper part number #341-21746-00-00 for the 1987 Yamaha SRX250. These parts are no longer available from Yamaha. You need 2 per motorcycle. The picture shows the old part and the 1st run with the flex filament.
I printed this using Yogi TPU filament and used no supports on my FlashForge Creator Pro. 0.3mm nozzle, 28 mm/s feed rate, cooling fan on, 70 degree print bed, and the cool function enable in Skeinforge, for 20 seconds minimum per layer to allow the previous layer to cool. Printed in this order, infill, loops, perimeter. The first layer of the overhang has a few droops, but not bad, and you won't see the droops when it installed
I printed the following version:
2 shells + perimeter, 98% fill, and they are too stiff. That used 2.295 meters of filament (1.75mm)
2 shells + perimeter, 40% fill, and they are stiff. That used 1.785 meters of filament (1.75mm)
1 shells + perimeter, 30% fill, and they are stiff. That used 1.574 meters of filament (1.75mm)
0 shells + perimeter, 30% fill, and they still stiffer than the rubber part, but maybe OK. That used 1.378 meters of filament (1.75mm)