The idea of getting an aluminum subframe for my VTR has been eating away at me for some time now (especially given all the weight savings I have already managed to realize). Due to its location high up and away from the c of g (especially towards the rear), I would suspect dropping weight here would have the most discernible effect on handling. While the strength of Al is not up there with steel (a concern for carrying a passenger), virtually all modern sportbikes use it for subframe fabrication (with Yamaha even using magnesium on the latest R6) so it is clearly up to the task.

With all this in mind, I just pulled the trigger on a subframe from a 98 CBR900RR (comes with passenger pegs). My goal is to alter/mod it such as to retain use of the existing (Sargent) seat and bodywork. I am not a welder and don't have a Mig or Tig machine so I'll obviously have to get someone else to do that end of the job but I'll try to do the cutting and fabbing myself. Hope it works out, if not I'm not out too much $$$$$.

P.S. A wet weight of 400 lb would be a wonderful thing

Here it is:

 

You should probably keep in mind that most alu subframes in modern bikes are a bit more sturdy than the steel ones they replace both literally and generation wise...

I made mine not as a straight copy, but added a fair bit of bracing and plates... It's still a whole lot lighter than the stock... And I'd actually guess somewhat stronger too, but that's just guesswork... If I hadn't managed to forget to take pictures of it, I'd show you... But basically a copy of the stock with smaller cross bracings...

 

I do plan to add a lot of bracing as I do carry a passenger from time to time. While I don't have a number as to the weight of the stock unit (still mounted on the bike....), I would imagine there are a few pounds to shed with this mod.

Hopefully it will work out (would sure be a lot easier if I was a welder)....

 

Well... I'm somewhere between novice and complete clutz with a TIG, but I make do... All according to my brother that does it for a living... That never stopped me from being to stubborn to have him do it for me though...

His assesment of my latest work was that it would be merciful to shoot me... Dunno exactly if that was opposed to shooting him, or not... But I did figure out he didn't think it was pretty... He did however say that nothing I ever welded is likely to break in a weld though...

Get a TIG and start practicing... It's useful in so many ways...

 

Any one have a weight difference on this? I really am curious to see how much weight would be saved.

 

Ballpark figures from me working with it, not piutting it on a scale (weighted the whole bike, was more interested in that)...

Before I started bracing it, when it was just a straight up copy of the original, mine was somewhere between 1/3 and 1/2 of the original...

Ended up somewhere around half the weight I'd say... And then I was bracing the hell out of it, I don't want it to fail since I frequently carry a passenger...