I dont know if its my net or PC but all of your images are gone? Again I would start the way I have and using extrude on edges, adding loops with poly split and getting it out that way. Its really not a hard one, just takes a bit of thinking and there will be moments you add/delete etc etc. Creating edges with split poly, then extruding edges and merging verts etc...just takes some time. What I did in that file only took about 30 mins....a few hours and you would have the basic shape, then tweak. There is always a ton of tweaking on mechanical parts, there is one here

https://simplymaya.com/autodesk-maya-...=186&sub_cat=9

Its not a motorbike but the technique is solid and gets you thinking outside of the square for a complex object (trust me I tried it without this tut and was stumped). Its not free but its worth it.

Cheers bullet