Thats the bike, I think the frame is unique but not sure about the strength it looks flimsy. I'll check the HP aswell as I'm 6,2 and 85kgs dont want it to struggle going up hill on power. Thanks for the pic and appreciate the advice.
I keep telling you don't reinvent the wheel here. You don't see them for a very good reason - it's a shit platform for what you want to do.
Also stop thinking about this thing in terms of aesthetics, you want to find an old bike, improve that old bike, and let the mechanical improvements guide how it looks. If you try to "force" a look on an 80's piece of shit you'll only get a bike that bolt rides and looks like crap. Also at 6'2" that 450 is freaking tiny. Stop trying to reinvent the wheel. you aren't going to be the one who suddenly starts a revolution because you made a cb450 look like all the other trash on pipeburn, you've never done this before so I don't think you fully appreciate how difficult it is to build a good custom bike. Take baby steps.
You're in germany, I can't imagine an airhead beemer is hard to find? Like an R90S or R100S? Europe is lousy with british and italian bikes as well and most of the italian stuff from the 70's is pretty great component wise (most use ceriani or marzocchi forks and shocks, grimeca or brembo brakes, etc).
As this is your first time you want a bike with:
1) a racing history for the model
2) a good solid knowledge base
3) a thriving aftermarket
4) a Factory Parts support including published service materials.
Only some honda CB's qualify here: the 1969-1976 cb750F, the 1967-1974 CB450, the 1975-78 CB400F, the 1968-1974 cb350, the 1979-1982 CB750F/900F/1100F. There are plenty of honda CB models that don't fit that bill at all like the 1979 til whenever cb400/450 hawk and cb360s, and other useless junk. For a long time the 1972-74 cb350F four cylinder was so forgotten honda didn't even stock service parts for it, now it is coming back but not to the level of any of the other bikes mentioned.
I have to think if you have to buy something with no parts support and no aftermarket a Morini 500 is way more interesting to own than a cb450 hawk. Look for that shit instead.
Other bikes you should look for:
airhead beemers (the big ones not the little ones)
I'm sure others will add to the list.
And before you cry about all those other bikes being expensive because you can't buy them for 500 euros...well...it's because they are worth it.