Simple V4 engine is here.

[marko138]

Originally Posted by goof2

The internet. Maybe the magazines will get a prototype to test. I doubt it will get much further than that.

Shitty.

[Dave]

Originally Posted by karl_1052

Well, those are all big V8s with heavy pistons and valvetrain. Did you expect this 1650cc motor to use the same size valvetrain as a 5000cc V8?
I posted those vids to show with a lightweight valvetrain(which this motorcycle engine could have) can rev to high RPM limits.
It all comes down to the ability to control the valves, and with light valves and good springs, there is no reason that a pushrod engine won't rev past 10K.

valvetrain and cam profile are important, but the real question here is geometry. If the strokes too long the piston speed can be a very limiting factor

[karl_1052]

Originally Posted by goof2

While there is no reason it can't be done there are 3 reasons it isn't commonly done. 1) It costs money to make that lightweight drivetrain, 2) the lighter they make the valvetrain the more issues they may run in to with reliability, and 3) with only 2 valves per cylinder it is more difficult to fill the cylinders with air, the benefit of higher revs.

According to the Cycle World article below the engine makes peak power at 7800 rpm. I doubt it redlines much above 8,500 rpm.

http://www.cycleworld.com/article.as...&page_number=2

I never said this engine had a high redline. You said pushrod motors cannot rev, and I proved you wrong.

Originally Posted by Dave

valvetrain and cam profile are important, but the real question here is geometry. If the strokes too long the piston speed can be a very limiting factor

Once again, my comments have nothing to do with this motor, I was just pointing out that pushrod engines can have high redlines.

[marko138]

Originally Posted by karl_1052

I never said this engine had a high redline. You said pushrod motors cannot rev, and I proved you wrong.



Once again, my comments have nothing to do with this motor, I was just pointing out that pushrod engines can have high redlines.

Get 'em, Tiger.

[karl_1052]

Originally Posted by marko138

Get 'em, Tiger.

at least you didn't call me Tigger.

[marko138]

Originally Posted by karl_1052

at least you didn't call me Tigger.

I'd never insult someone like that.

[goof2]

Originally Posted by karl_1052

I never said this engine had a high redline. You said pushrod motors cannot rev, and I proved you wrong.

Once again, my comments have nothing to do with this motor, I was just pointing out that pushrod engines can have high redlines.

I wasn't trying to state that high rpms with pushrod valve actuation were impossible. I know it can be done and has been done. I phrased my statement poorly though. I can definitely see how it could have been taken that way.

[nhgunnut]

It is an interesting concept and if it gets out of the prototype stage I would love to ride one. In terms of number as I recall the early prototype numbers on the Victory Gen 1 engines (the named Hammer) reported 100 + horse with 105 foot pounds of torque when the arrived in 99 it was 72 and 99.