Kawasaki's Two-Stroke is Real, the KX327 is Here

steel

Yes.  Oops.

There's been plenty of Tubular Aluminium Motorcycle frames.

In large scale production - just check some of Triumphs Road Bike models, over the years.

They were influenced by Spondon - who were doing Round Tubular Aluminium frames, from many years back. Indeed, I think Triumph bought Spondon. Sort of how Royal Enfield bought Harris Performance.

If you want see Real Aluminium Frame Porn, look up OVER Racing, from Japan. They've make So Many spectacular frames, ( many with their signature Oval Tubing) for so many engines - their Harley Road Race ( and, other Monster Twins, such as the Yamaha MT01 engine - the first of those had the Oval Tubing, but a later one, the OV-23XV, that they tried to qualify for the  Suzuka 8 hour, a couple of times,  which you can find pictures of easily, had a, shall I say, ' Rectangularized Oval ' tubing set to them) frames, Real  stand outs. 

Pierbon ( I'm sure I've got that spelling / name wrong) have done quite a few Round Tube Aluminium frames - I think another company, that starts with 'P', that I think was prior too, or, after the setting up of Pierbon, did quite a few round tube Aluminium frames.

And, I've seen blokes do Ducati TT2 type Frames  ( I make 4130 versions of them ) in Aluminium Tubing( and Not in, say, 7000 series that many 'mixes' Don't demand After Weld heat treatment) . But, they've been Frightening to me - as, they seem to have used the same sized tubing as 4130 ones, with NO heat treatment after weldment. So many welds, so many joints, such small Aluminium Tubing, So Much base metal / weld point softening.  I think they would be terribly unsafe, and Hope they have been largely, Garage Queens. 

As a frame maker beginning in the 70s - go to the 2nd (?) page of the 70s thread, you'll see the Aluminium Beam framed full, Long Travel Suspension BMX / DH bike I made in 1975  : I think a few years before you'd see Spain's JJ Kobas / Cobas do Aluminium Beam Road Race frames. Hey, it was the easiest way for a kid with a drill press and some files to get the BB, SA pivot parallel, and the Head Tube at 90 degrees and centered to them !

I've So Admired So Many Makers work - while being quite a critical b**tard towards the crap that some do. And , a Lot of crap, comes from the  so called ' Professionals' !!

Then you have TMs - I can look at their frames all, day, as there's No Hidden, Ugly Welds ( often filling Big Gaps)  to them, - unlike so many  mass produced frames. 

And, there have been many  Steel / Aluminium combination Frames frames done. 

One  of the first, in the 50s, was on one of, or some of,  the Greeves Motorcycles models.

 On some of the Honda EXP AR 2 strokes, they had bolt in lower cradles in steel, bolted to the SA plate area , and, thence to the  downtube(s). Also, on a few of the CR250 Auto prototypes, they had that set up.

Basically, if you can Think It, it's Been Done.

 There's not much new, in Metal Frame fabrication - even 'printing' has a fair few years to it now . In my work at a couple of  Unis, I get to see the Metal ( and other materials) Printing, and it Absolutely Baffles this Old Man. Mind you, the use of a Hacksaw, Files, Lathes / Mills and  and Welders etc, baffles the many of Students and many of the Professors  that I instruct / work  with ...... 🤪

I do hope to see Real pictures of the 327 , soon. Though, they probably are out there by now, and I've just missed them. 

Haha, that’s my old 07 kx250 with the buckled frame

What did you Hit / Do to create such a ' Modification ' ?

It's a bloody Doozey! 😵

Bought it that way, best $1000 I ever spent. Guy had a head on with a vehicle at a riding area. Bike was pretty much brand new except for the bent frame. I was able to find a frame on ebay and rebuilt the bike. Somehow the forks were straight, verified checking runout with a lathe. 

How it looked after the frame swap.

The first one that came to my mind is the original 650 SV. Oval alloy tubes trellis frame.

These are round-ish in shape. But all the aluminum tubing is hydroformed, and/or extrusion cast in sections and welded together. That 650 frame represents the infancy of hydroforming, sort of like the CGI in The Mummy.  On mx bikes the frame spars are hydroformed, and the Y on the front is an extrusion casting.  The twostroke YZs are pretty much all extrusion cast.