Ninja 650R: Speculate on long-term reliability.
So Im reading about the new Ninja 650R. One thing that really struck me was that the new engine has an all-aluminum cylinder with no liner, just a good layer of hard chrome plating, in order to reduce the size and weight.
This kind of bothers me.
I work as an engineer in a machine shop. I know my aluminums, and I know my hard chrome plating.
Standard HCR has great hardness - 65-70 Rc - but it's pretty brittle too. It doesn't match the expansion coefficient of aluminum as well as I'd like.
Does this sort of fabrication have much potential for long-term wear and tear? At first glance, I'd say no. The chrome layer is pretty durable -
(I don't know how thick they're going, anyone have a micrograph?)
- but it would seem that the plating should start to crack and fall away from the cylinder wall after a certain amount of thermal cycling.
On the upside, I suppose it wouldn't be all that hard to get the cylinder re-plated and honed back to size when it got worn... or is the engine modular enough that you can just bolt on a new cylinder?