Originally Posted by rock&rollfrenchfries
just to clear this up... Is a 600 4 cylinder such a small bike not to be turboed?
or are we really just talking about scooters and small twins and stuff?
I would honestly prefer lowering the compression of a modern water cooled 600 than trying to go the route of a air cooled under 400cc twin. Main reason being turbocharger availability and heat. The water cooled bike will almost always be the easier route, not to mention most modern (1985+) machines that are water cooled have a pretty nice backing when it come to aftermarket parts from valves to crankshafts.
Basically, I think the general consensus, at least as I know it, and I am pretty knowledgable, is that when it comes down to it, make sure your not just throwing money at a motor in hopes of boost. Know your internal specs, like, what is your crank and rods made from, is it steel, iron, aluminum, is it forged, cast, etc. Know your enemy basically.
Another thing to look out for is how thin the cylinder sleeves are, how thin the block is around them, how much room is there for things to flex before they break? The old Virago flat trackers started to flex casings at 80-90hp but could do half a season making that much. It's a roll of the dice unless you know just how far you can push it.
What it comes down to, 100%, is knowing what your up against. I been talking with my turbo guru's lately, and it sounds as though your best off talking to someone who knows something about this sorta stuff. Talking to Poopie this evening, myself and Motohorho both said the same thing without knowing the others agenda: pitot tube size and turbo/engine flow matching matter sooooo much more than charge pipe diameter, but, it's easier to tune to a bigger charge pipe than a smaller one. Once you understand that sort of math, it all makes much more sense. Crazy, all over the board to someone who doesn't know what I'm talking about, but it's these hurdles to jump in order to know what is turbocharger friendly and what isn't.
Every bike I have considered turbocharging, save for the bandit, was in the ideal of a pass or two and then a idle period to shut down running feed and return pumps for oil. All my ideals of air cooled turbocharging is based on 3-6,000 mile rebuilding/spec check phases and insanely tight tuning schedules. I don't mess around with a potential wheel chock at 100mph.
I know all too well how it feels to block the rear wheel at 120mph on a standup hill crest wheelie. Still unsure how I didn't go down...
You can barely see the B12 and the F3 waaaaaay the hell down the road on the right where the Bandit finally stopped sliding. I was standing up the whole way steering it through the massive "drifting" episode once it locked up. Wrecked a brand new Pilot Power rear as well. Less than 500 miles on it.