[AT] Rationale for firing orders

[BetCleve321 at aol.com]

In a message dated 3/22/2004 4:37:37 PM Eastern Standard Time, chill8 at cox.net 
writes:
I think that nothing  nothing has helped the popularity of JD's about as
much as it has Harley Davidson.  And that is a good bit.

Charlie
Well, Harley Davidson engines are spaced quite differently than poppin' 
Johnnys. JDs have a 180degree crank with the pistons rising and falling at 
different times. One up , one down.
HDs on the other hand have their pistons rising and falling together although 
the two cylinders are splayed 52 degrees apart.  You do the math. Firing 
sequence will be slightly uneven as a result rather than a smooth beat such as a 
Triumph or BSA twinn. Balancing problems are hell, The JD layout has primary 
balance worked out but firing impulses are uneven.
They both sound good though.

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