Engine Internals Harley-Davidson
by Pat Goss
When you think motorcycles, you think Harley-Davidson. It's truly an American icon and one of the most recognized names in the world. So when our Pat Goss had the opportunity to get up close and personal with a Harley-Davidson engine, he jumped at the chance.
PAT GOSS: Seeing a Harley-Davidson motorcycle on the street, well that's an everyday occurrence. But here's something you're only going to see on Goss' Garage. We have a cutaway Harley-Davidson engine. And to give us a rundown on it we also have Lyndon Abel, general manager of Patriot Harley Davidson in Fairfax, Virginia. Lyndon, welcome back to the show.
LYNDON ABEL: Thank You.
PAT GOSS: Alright let's get this...
LYNDON ABEL: Yeah let's see how it works.
PAT GOSS: Yeah, let's get it moving.
LYNDON ABEL: Rare opportunity to see the inside of your motor. Turn it around from the outside.
PAT GOSS: 'Course we're seeing the piston move up and down.
LYNDON ABEL: Right. See it coming down on the cylinder bore, back up, and now we see the exhaust valve opening as the piston comes back up on the exhaust stroke.
PAT GOSS: Now right here we're seeing the valve seat.
LYNDON ABEL: Yeah.
PAT GOSS: The valve's seat is hardened metal to protect the aluminum head.
LYNDON ABEL: Yeah, something that uh, you're rarely going to see, but if that, if that steel valve was smacking into that uh aluminum cylinder head it would tear it up in no time. This protects it.
PAT GOSS: And of course the wrist pin, which everybody knows, well they know the name anyway, the wrist pin connects the piston to the connecting rod. And the connecting rod has to swing back and forth with the movement of the crank shaft.
LYNDON ABEL: Sure.
PAT GOSS: That allows it to do it. Now that's the same in all engines, whether it's in a car or a boat, or whatever it might be.
LYNDON ABEL: Absolutely.
PAT GOSS: But now, down at the bottom, at the crank shaft on a Harley-Davidson, we have to get that power from the crank shaft back to the transmission. And that's where things change.
LYNDON ABEL: Yeah this is pretty unique for a Harley-Davidson motor. And it's one of those iconic looks about a Harley-Davidson that everybody notices right away. And obviously we have the outer chrome cover removed, but this is the primary drive system. And what you see here is the compensating sprocket. And it's taking the power from the motor, and turning this chain, which comes across this adjuster, whose job is to keep the chain at its proper tension, and then ultimately turns this clutch basket, which sends the power to the transmission.
PAT GOSS: And the clutch is really unique on a Harley. It's been around for decades, but it works so well. Give us a little run down on it.
LYNDON ABEL: Sure. It's a very enduring design. As Pat as you're pulling that clutch lever, uh these two ramps separate. And in those ramps are crevices with a ball in between. So as this inner ramp pivots forward, the ball comes out of the crevice and pushes the ramp in, which presses against the push rod, which comes all the way through the main shaft of the transmission and ultimately presses against this adjuster here. And you can see it releasing the pressure from this diaphragm spring that allows these clutch plates to separate.
PAT GOSS: Yeah it's pretty amazing, and it works so well, that it's hard to imagine. Alright, now one of the big things here, all of these moving parts, proper maintenance is an absolute must.
LYNDON ABEL: If you want them to last, preventive maintenance is a must.
PAT GOSS: So follow the owner's manual.
LYNDON ABEL: Always.
PAT GOSS: Lyndon, thank you.