Simple V4 engine is here.

[Rangerscott]

http://www.asphaltandrubber.com/bike...ect-injection/




A wopping 1650cc displacement. I bet it's got plenty of torque but I wonder what the power band is like with only two valves per cylinder.

[goof2]

Originally Posted by Rangerscott

I bet it's got plenty of torque but I wonder what the power band is like with only two valves per cylinder.

It should be a relative torque monster with two valves per cylinder. Pushrod valve actuation should also require that the redline be kept relatively low.

[karl_1052]

Originally Posted by goof2

It should be a relative torque monster with two valves per cylinder. Pushrod valve actuation should also require that the redline be kept relatively low.

really?
http://www.myvideo.de/watch/4532350/...crank_9000_rpm

http://www.youtube.com/watch?v=gqK8N03TGrQ

http://www.youtube.com/watch?v=Pwsr2IbnyT8

[Dave]

Originally Posted by karl_1052

really?
http://www.myvideo.de/watch/4532350/...crank_9000_rpm

http://www.youtube.com/watch?v=gqK8N03TGrQ

http://www.youtube.com/watch?v=Pwsr2IbnyT8

aww thats cute, now show me someone who is winding their pushrod smallblock to 9000+ every day on the street for oh, say 40,000 miles?

[goof2]

Originally Posted by karl_1052

really?

Those are weak examples. I'll bet the Mercedes/Ilmor pushrod engine from the 1994 Indy 500 redlined north of 10k rpms. That also has about as much to do with a production engine for the street as what you posted.

[karl_1052]

Originally Posted by goof2

Those are weak examples. I'll bet the Mercedes/Ilmor pushrod engine from the 1994 Indy 500 redlined north of 10k rpms. That also has about as much to do with a production engine for the street as what you posted.

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.

[goof2]

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.

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

[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

[marko138]

Alright.