[TimNC]

I have read that the 650's 2 cyl's go up and down together or 360 degree rotation. Is this true? If so, do they fire together? I'm somewhat confused with this since this is the first time I have EVER heard of such a thing. :?

Tim

 

[pauljo]

Harley Davidson motors work that way. The old Triump British twins also worked that way. I read the same article - don't know if it is accurate though. I know my 650 doesn't sound (or shake) like a Harley... But being a parallel twin vs a v-twin would make a difference, plus they smooth it out via counter balancers.

 

[allwalk]

I have read that the 650's 2 cyl's go up and down together or 360 degree rotation. Is this true? If so, do they fire together? I'm somewhat confused with this since this is the first time I have EVER heard of such a thing. :?

Tim

Yep its true. They have a huge counter balance to smooth things out.

 

[TimNC]

Ok. So both pistons run together - fire together - acting as one large single cyl. I'm assuming then that the purpose is torque since hp would suffer in such a setup.

 

[Wes]

Ok. So both pistons run together - fire together - acting as one large single cyl. I'm assuming then that the purpose is torque since hp would suffer in such a setup.

Pistons go up and down together (360 degree engine) but still fire alternately. This was a common configuration with British twins as well as lots of the early Japanese twins. This config only requires one set of points or one pickup. It still has one cylinder firing for each turn of the crank so power characteristics are pretty much the same. Rocking couple is eliminated but primary imbalance is increased, smoothed out by the use of dual counter-balancers.

 

[TimNC]

What is the performance benefits of such an arrangement? Also, thanks for the help.

Tim

 

[NormanB]

Ok. So both pistons run together - fire together - acting as one large single cyl. I'm assuming then that the purpose is torque since hp would suffer in such a setup.

I do not think there is a relationship between power and firing order, power is all about the swept volume and pressures blah blah.........

:shock:

 

[pauljo]

I think it is torque vs horsepower too. The torque curve on the AN650 is almost a straight line - high, and very flat. I was told that by someone at Scootercade who had put theirs on a dyno. I think it was "Magyver". Horsepower is only moderate for a 650. But the high torque is needed for good performance with the ECVT tranny.

 

[TimNC]

Makes sense to me too Pauljo. I am surprised by the massive torque this little engine develops. I have owned a 650 in another brand before but nothing like this torque-wise. But then it was a 180 degree rotation. Thanks again for all the info. The more I learn about the burgy the more I like it.

Tim

 

[vfdcaptain]

It's simply amazing what you can learn on this website!

 

[TimNC]

Simply amazing!

 

[Randy]

vfdcaptain wrote

It's simply amazing what you can learn on this website

And most of it is useful to :thumbright: