Harley needs to ditch the roller crank

[otto_kretschmer]

Why is Harley Davison still using a pressed together, tinker toy, roller crankshaft?

Has anyone else wondered about this? I'm not a harley fan and i doubt I'll ever get one but I do like the Road King and if an Evo Road King with a carb came around that was at the right price I'd be tempted.

I understand their desire to have both jugs in the same plane. It makes a nice good looking engine and its thin, but they could use knife and fork plain bearing rods like the merlin/daimler/allison aircraft engines of ww2 used.

If they used plain bearing rods like most cars they would have to offset the cylinders the distance equal to (about) the width of the rod big end. This may improve cooling the rear jug.

Maybe the milwaukee 8 will be the last Harley with this non-sense and the revolution engine is the future. If this is true I think they should go with a 90 deg twin and not have the split crank pin or counter balance shafts the revolution probably has. New Harleys would sound like a Ducati and thats not bad.

[otto_kretschmer]

why? WHY?

makes no sense

[sc_rufctr]

[otto_kretschmer]

Originally Posted by sc_rufctr

Harley could still have the patato-patato sound and not have the tinker toy crank



the 45 deg v angle still made sense in 1936 when the knucklehead came out

[Zeke]

Originally Posted by afterburn 549

If they died tomorrow most of us would not care

Most of us don't ride. Or did you mean most of the Harley owners? That I would argue.

I don't know what it is because other MC manufacturers have tried many times to produce a U.S. made bike and fell off their kickstand. So, it can't all be the COO.

This is a classic case of 'if it works, don't fix it' (even if you don't understand it). HD does make this mistake now and then.

If I was CEO of HD my priority would be quality of build followed by market observation. And Id keep the price fair by employing manufacturing efficiency. IOW, the Porsche model. How is rear engine car even possible these days?

If you just stepped off a spaceship, you'd wonder the same.

[rfuerst911sc]

I wonder who holds the patent license for the V-Rod engine ? Harley or Porsche ? Was that considered a good engine ? Is it still considered a modern design ? Just curious if it could be dusted off and used again . Harley knows the engine , knows the frame requirements and supporting hardware needed. Production capabilities for the engine would have to be looked at . Just curious .

[Rot 911]

Originally Posted by otto_kretschmer

Has anyone else wondered about this? I'm not a harley fan and i doubt I'll ever get one but I do like the Road King and if an Evo Road King with a carb came around that was at the right price I'd be tempted.

Here’s your opportunity. This one is just out of Detroit Michigan. If it was a bit closer I’d give some serious thought to buying it. Even though I have more motorcycles than places to store them right now. It’s on the adventure riders forum.



“ 1995 Harley Davidson Road King: $7,000.00
- 27,000 miles. Evolution motor.
I've gone through this bike and replaced anything (especially rubber) that I questioned due to age such as the drive belt, oil hoses, gaskets, motor mount. This bike has an Andrews EV27 cam, S&S lifters, S&S steel breather valve, mild carburetor work, open air cleaner, true dual exhaust, slip-on mufflers, chrome starter, chrome forks, newer Road King handlebars, Mustang seats. Lots of little add-ons. Just installed new Bitubo shocks.”

[otto_kretschmer]

Originally Posted by Rot 911

Here’s your opportunity. This one is just out of Detroit Michigan. If it was a bit closer I’d give some serious thought to buying it. Even though I have more motorcycles than places to store them right now. It’s on the adventure riders forum.



“ 1995 Harley Davidson Road King: $7,000.00
- 27,000 miles. Evolution motor.
I've gone through this bike and replaced anything (especially rubber) that I questioned due to age such as the drive belt, oil hoses, gaskets, motor mount. This bike has an Andrews EV27 cam, S&S lifters, S&S steel breather valve, mild carburetor work, open air cleaner, true dual exhaust, slip-on mufflers, chrome starter, chrome forks, newer Road King handlebars, Mustang seats. Lots of little add-ons. Just installed new Bitubo shocks.”

Is this from the guy selling several bikes including a BMW R1200GS? I think I've seen it.

[otto_kretschmer]

Originally Posted by rfuerst911sc

I wonder who holds the patent license for the V-Rod engine ? Harley or Porsche ? Was that considered a good engine ? Is it still considered a modern design ? Just curious if it could be dusted off and used again . Harley knows the engine , knows the frame requirements and supporting hardware needed. Production capabilities for the engine would have to be looked at . Just curious .

take a look at the v-rod engine and compare it to the pan america engine

[otto_kretschmer]

I don't think anyone would stop buying harleys if they sounded like a ducati



a lot of the clatter you hear on the ducati is the dry clutch tamborine rattle

[stevej37]

Would a different crank solve the 'inability to idle' problem with Harleys at stop lights?

[ckcarr]

If they wanted that they would just go buy a Ducati.

I have a Harley, a bunch of BMW's. Had one Ducati.

Each has it's own purpose. Although all are united with one purpose - to take my money...

Harley is branching out with (for example) the engine is the Pan America. But, like BMW, that essentially have three different engine configurations, Harley will always have the V-twin, like BMW has the boxer. Not everyone is looking for Ducati sound or performance.. Especially if you're in nowhere Wyoming and there's no dealer anywhere..

Originally Posted by otto_kretschmer

I don't think anyone would stop buying harleys if they sounded like a ducati

a lot of the clatter you hear on the ducati is the dry clutch tamborine rattle

[otto_kretschmer]

Originally Posted by afterburn 549

I did not understand I guess? I thought this thread was about the nuances , the romance, lunacy and archaicness of the V twinn

This thread is about the multi piece harley crankshaft and its deficiencies. The problem lies with Harley wanting to keep the 45 deg v-twin. A 45 deg V makes for a tall engine and as motorcycles grow the displacement increases. With 45 deg V being so narrow, as the pistons get bigger they will start interfering with each other as they rotate. This requires longer rods to push the pistons away from each other and this makes the engine even taller. With a really tall engine there isn't room for an oil sump so Harley had to go with a dry sump oil system.

The multi piece crank tends to get out of true and when its gets bad enough the engine self destructs and your looking at replacing the entire engine. Some people are even taking the cranks apart to be straightened and welded. I wouldn't expect the welds to hold in the long run.

If you have a twin cam and you upgrade the cam drive from chains to gears, the problem gets worse much sooner. The chains can work with more misalignment than the gear drive.

Harley isn't alone in this kind of stupidity. There is a car manufactures out there who made an air cooled car and when the emmissions regs got tighter, they made the engine run hotter by reducing the number of fan blades and had some kind of thermal reactor in the exuast.

I may have one of these cars in my garage right now but the 5 bladed fan and reactors are long gone.

[Rot 911]

Originally Posted by otto_kretschmer

Is this from the guy selling several bikes including a BMW R1200GS? I think I've seen it.

Yep

[Jeff Higgins]

I put almost 120,000 absolutely trouble free miles on my 2000 Road King, an 88 ci Twin Cam. It only died at the hands of an F250 that ran it (and my wife and I) over. I have a couple of riding buddies who topped 200,000 miles with their Twin Cams before deciding to rebuild them. My current 2013 only has 40,000 miles on it, but that's only because if I am riding solo, I usually choose my Ducati...

Really, the "proof is in the pudding". Harley suffers a good deal of criticism, but out in the real world, there are more riders riding Harleys than, quite literally, every other make combined. They have had a 50%-ish market share of "heavyweight" motorcycle sales for an awfully long time (decades, really). Let that sink in - the big four Japanese, the Italians, Germans, Brits, Austrians, and everyone else manufacturing "heavyweight" motorcycles (including Indian, their only "American" competitor) are fighting over what is somewhere around a 50% share. Harley are clearly providing something that riders are looking for, the critics be damned.

Pressed together roller crank? Meh... so what? If it provides a couple hundred thousand mile service life, most folks are going to be quite happy. No, it does not respond well to hot rodding it for significantly more power - it will twist all out of alignment. Is that Harley's problem? I hardly thing so. When used within its design parameters, it has proven to be an exceptionally long lived, trouble free design.

Harley did actually address this "problem" in its last generation XR750. They went to a plain bearing crank in that motor as power climbed over the years. They were able to keep the "knife and fork" rod bearing design, keeping the cylinders aligned longitudinally, so it does appear entirely possible. So why would they not incorporate this on their road bikes? It's actually much cheaper to manufacture. Seems "obvious", doesn't it? But none of us are Harley engineers. We don't have access to their data. Yet we criticize their decisions, believing we know better, and that there are "better" solutions that are "obvious" to us...

[javadog]

Suzuki used roller bearing cranks on lots of bikes and many of those are still raced, making ridiculous power. Those cranks can work just fine…

Porsche used roller bearing cranks, back in the 1950’s….

[otto_kretschmer]

Originally Posted by Jeff Higgins

But none of us are Harley engineers. We don't have access to their data. Yet we criticize their decisions, believing we know better, and that there are "better" solutions that are "obvious" to us...

I'm an engineer and I know that engineers don't make marketing decisions. They are given an envelope to work in and they are limited to those boundry conditions. I see some things I like in Harleys; pushrods and hydraulic lifters. I also see things I don't like; roller cranks and dry sumps.

[otto_kretschmer]

Originally Posted by javadog

Suzuki used roller bearing cranks on lots of bikes and many of those are still raced, making ridiculous power. Those cranks can work just fine…

Porsche used roller bearing cranks, back in the 1950’s….

BMW used a roller crank on the /2 models in the 60s. When they came out with the /5 in 1969 they went to a plain bearing crank. I've rebuilt two airheads with the plain crank and they're fairly simple. Most BMW dealers can install new main bearings. If i find a /2 someday and rebuild the motor I'll have to find an old timer somewhere to send the bottom end to and have him do the work.

Roller cranks were dropped a long time ago by most manufactures, except Harley and anyone still making 2 strokes.

Some manufactures keep a feature that identifies their brand. Porsche has the rear engine flat 6, Ducati has the desmodronic valves and Harley had the 45 deg aircooled engine. Porsche dropped aircooling but kept the flat 6. Ducati dropped the desmo for their new v4 adventure bike and Harley is on its way to getting rid of the roller crank. The new Pan America is probably where Harley is going in the future.

[Jeff Higgins]

Originally Posted by otto_kretschmer

I'm an engineer and I know that engineers don't make marketing decisions. They are given an envelope to work in and they are limited to those boundry conditions. I see some things I like in Harleys; pushrods and hydraulic lifters. I also see things I don't like; roller cranks and dry sumps.

I am (or was, I'm now retired) a mechanical engineer by profession as well. I became well aware of the frustrations of having engineering decisions being made by marketing, management, and finance people. These are, unfortunately, the constraints we have to live with in modern manufacturing.

I do not, however, believe that the continued use of the roller crank, nor the dry sump oiling system, are anything but purely engineering decisions. Both are more complex and expensive to manufacture than their alternatives, a plain bearing crank and a wet sump. Neither are perceived by their customer base as "signature features" of the brand. Hell, I would venture that the vast majority of their modern customer base do not even know what these things are, and would never base purchasing decisions upon these features. If anything, the "bean counters" would be pushing the engineers to eliminate these expensive solutions in favor of cheaper ones. Alas, there must almost certainly be compelling engineering reasons for keeping them, at least until the designs that utilize them are superseded completely.

[otto_kretschmer]

Originally Posted by Jeff Higgins

I am (or was, I'm now retired) a mechanical engineer by profession as well. I became well aware of the frustrations of having engineering decisions being made by marketing, management, and finance people. These are, unfortunately, the constraints we have to live with in modern manufacturing.

I do not, however, believe that the continued use of the roller crank, nor the dry sump oiling system, are anything but purely engineering decisions. Both are more complex and expensive to manufacture than their alternatives, a plain bearing crank and a wet sump. Neither are perceived by their customer base as "signature features" of the brand. Hell, I would venture that the vast majority of their modern customer base do not even know what these things are, and would never base purchasing decisions upon these features. If anything, the "bean counters" would be pushing the engineers to eliminate these expensive solutions in favor of cheaper ones. Alas, there must almost certainly be compelling engineering reasons for keeping them, at least until the designs that utilize them are superseded completely.

There is a good chance that Harley is keeping the roller crank because they're already tooled up for them so why get rid of all that capital if you can tweak the design a little to keep everything working (sorta). Eventually they're going to have to go complete water cooled for emmissions and to make the power that the marketing people want.

If I was in charge of Harley, I'd go with a 90 deg v-twin, water cooled and pushrods with hydraulic lifters. Basically I'd tell my engineers go get a Chevy 454 and slice off two cylinders and build a motorcycle around that. it would be a 300k mile engine.

I've read somewhere this is what Motoguzzi did in the 60s when they came out with their 90 deg air cooled twin. They took a chevy of that era and used the same bore and stroke and cam profiles and geometry.