Why do Harley Davidson engines rumble/shake?

J

Jay C

New member
I've noticed that HD engines "rumble" a lot more than import Big V-Twins. This is very noticable at idle. With aftermarket pipes, import and domestic V-Twins can sound similar, but the imports don't rumble/shake. Why?
 
It's the firing order, it's the way Harley's were designed. As for being an old design, they may be, but so is the pushrod V8 engine, if it works and people buy them whey change a tried and proven thing.
 
I don't think anybbody is right. Before EFI, Harley had a "waste spark" ignition. That means both plugs fired at the same time. This caused the distinct "potato-potato" idle. The only inside counter balanced engines I know of were the "B" engines which were only used in rigid mount engines( Softails). With EFI you have to use a "firing order", now the plugs fire one at a time. If what Choppy says is true why can you time your back cylinder 10 degrees different than the front one? What you notice most vibrating are the handle bars. That is because of the rubber mount engines that they now use. Once you get off idle the vibrations go away. I know the local HD bashers will disagree, but most of them never sat on a Harley anyway. BTW Harleys do not have over head cams.
 
Cylinder firing sequence. It's part of the "allure".

As is little bits and pieces falling off.

(ninebadt...-> They DID get overhead cams. Just 30 years after the rest of the world...)
 
Choppy's got it,.... Older models did not have a counter-balance system. The newer ones do. ....Ain't it a thing of beauty? (turn your sound way up) http://www.youtube.com/watch?v=RS8e9LAMbc0

There's gotta be a reason why every single manufacturer on the planet has tried to copy it...
 
The same reason they have low torque and low horsepower but huge engines, are extreamly heavy and drive like a cement truck.....Ancient technology that they never bothered to update.
 
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