Future of the Inline 4?

The Suzuki inline 4 has done zero in the MotoGP arena because it doesn't exist...the GSR-V is a V4.

 

My bad. Must have had a mid-life moment. I meant Kawasaki"s inline4.

 

CNC isn't magic, it's just a method of controlling the machine. You still have to hold tolerances in more dimensions on a V4 engine than an inline. CNC doesn't make that any easier because the operation is just inherently more complex. You're now intersecting two planes (each cylinder bank) and a line (crank axis), rather than just one plane and a line.

Even the cylinder heads are more expensive, simply because you have to process two castings instead of one. With an inline, once the head casting is in the machine, all the operations are done at once. With a V4, you have to machine two castings and that just costs more because you spend more time fixturing and indexing the part. You also have twice as many camshafts to grind (a camshaft being a fairly complex part).

As for the V-Max engine, it's a tank they took out of the Venture touring bike. The reason they don't use it in the R1 is because it's completely unsuitable for the job. It's too long, too heavy, and just won't fit.

Honda has stated repeatedly that the V4 engine configurations are more expensive to manufacture than the inline fours. They've said it since the RC30 and RC45. It's never been a big secret.

 

Well, I don't think you are talking about a lot more money to produce the V over the inline. I'd doubt that it is more than a 2-3 percent difference in the total cost of the bike.

I'm wondering why someone doesn't try an inline 3? I don't think Triumph has an inkling to race their triple, but I wonder if others have explored that concept further. I guessing it could end up being the best of both worlds.

 

1985 VF500F Interceptor as an example.

The cylinders and the crankcase are one piece. That's what drove the cost up.

 

I see... that's makes sense.

 

Except that the CBR600 and I think the CBR9 family use the same integrated crankcase and cylinders.

But the V4's are still more expensive to build. How much more, I don't know. But that's the story that Honda has been sticking to for years and I see no reason to believe they're lying about it.

 

I think inline 3 is the way to go. From everything I understand the i-3 in theory could have the best power/weight ratio out of any configuration. Look at the aprilia gp bike. And of all the naked street bikes the triumph s-3 blows away the field in midrange torque. Plus they sound cool. Isn't the fp-1 a tripple?

 

You do realize that the Aprilia GP bike is the one of the lowest in horsepower and is the only one that isn't at the minimum weight standard yet?

Seriously though, I've heard the same thing about the potential power to weight ratio. It is just not the best configuration based on MotoGP rules because of the minimum weight rules. The 5 cylinder supposedly is the best with the given rules... according to Kenny Roberts, Sr. and Honda engineers.

but that Triumph triple does sound good.

 

A V engine will always be more expensive to produce. They will always require more time for tuning. Would people buy them? Yes, but not in mass numbers. (I'm speaking of serious sportbikes) Naturally, we'll pay for the lack of sales with increased cost.

I don't like the way a V engine (four stroke) feels. I've ridden a RC-51 and a VFR800. I was disappointed with both. They both felt like they were misfiring compared to the smooth running inline fours.

I'm not against V engine bikes. I have two. A TZ250 and a RZ500.

My everyday streetbike is a GSXR1000, which has a buttery smooth engine.