Discussion 2-stroke revival?

Thanks @aky141, but 2 rebuilts in 5 years points to a durability issue (reliability might have been the wrong word to have been using. 33hp sounds like a 250 Ninja, but I'd expect 50,000 before opening the motor, and even then it would only be valve shims. That's what it's competing against. For a handy-man enthusiasts, 2-stroke isn't so bad, but they are less likely to buy new.

 

You've done well @Murdo to 20,000, I just need to bolt 3-4 maico engines together to get some horsepower to compete with the 4-stroke supersports, though.

 

That is 12,000-15,000km a year @aky141 so you've clocked some kms, too. But, again, compare it to a 250 Ninja or XR250, where they might only change the oil at the intervals you're changing pistons. New buyers like vehicles they can just get in/on and go; they buy new so they don't have to worry about getting stuff fixed. You and I have no gripes about changing a piston every couple or years, but they are different, they mightn't even know where the oil goes. Maybe you just ignore those if you're building a 2-stroke, but who's left?

 

So, I've been thinking about this some more and thought a 500cc 2-stroke isn't going to make enough power to compete against a litre 4-stroke (it would take a lot of tuning and probably be the world's scariest powerband!). Well then, why not litre for litre? 1000cc 2-stroke, and not that dual-CR500, but a wet-sump triple. Take a triumph 955i and shave down the block, drop in tall pistons and have a supercharger for forcing the induction. Otherwise you'd have to use a V-4 or cross-ply motor to spread the firing order out.

 

2-stroke dirt bikes are a different story. 125 are awesome fun, but I'd disagree with @maelstrom and @KICKERMAN360. 4-stroke dirt bikes are superior - better power-delivery control and better fuel economy, leads to better a race bike, especially enduro. Though I'm thinking Finke and Dakar. I prefer the 4-stroke bikes, but I enjoyed 125 and would like one again; yet to try the much-raved-about 300.

I was more on about road bikes. I know there are differences between the engines, and I'm sure die-hards and purists on each side.
The CITS system looks like what they use in ship motors, but I'd have do the research to confirm. But new engine designs come out every other week, but no manufacturer wants to touch them; maybe burnt fingers from Wankel rotaries or from dealing with IP licencing issues. Search US patents office or google it, you'll find heaps. Orbital Engines is an aussie group that tried to launch a new motor, now their main income is the 2-stroke injection system on the e-tec outboard motors and aprillia scooters. No rotary motor from them. There's a lot of clever stuff that people have made that disappear because big business wouldn't take to the point of success. Carbon brakes almost joined that graveyard, too.

 

Oh, I remember, the vfr had no room to shave the block down for a side-port cylinder. It would mean a taller piston. But I think the stroke is the shorter, so the pistons would be much the same...