Author Topic: modern crankshafts  (Read 1723 times)

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Online PoorUB

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Re: modern crankshafts
« Reply #50 on: April 13, 2018, 09:30:33 PM »
"Say you took the current bagger, added a forged plain bearing crank, and add some suspension travel  and leave the rest alone. What would be wrong with that?"

Nothing wrong with it. But what does that buy me? Nothing. So why change? For the sake of change? Seems to me it's an excercise in polishing a turd! Perhaps it would make a lot of people that are dissatisfied with Harley-Davidson products, as they currently are, for HD to outsource the design and manufacture to Honda, and stick HD logos on the tanks. But the truth is, if they did that, it wouldn't give us anything to complain about anymore.
 :hyst:

-JW

You don't want a better crankshaft with added dependability? Better ride?

I don't know why you guys have to go to the extreme. I have never said to go by the way of the Japanese imports.
there is a large amount of grey area in between. Sad part is perhaps HD is unable to engineer a decent engine design on their own.

Keep the 45 degree twin, keep the single pin crank, but get rid of the crank run out, (Just added cams to mine, .007" run out!) and add some suspension travel!
I am an adult?? When did that happen, and how do I make it stop?!

Offline FSG

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Re: modern crankshafts
« Reply #51 on: April 13, 2018, 11:48:14 PM »
Quote
er, added a forged plain bearing crank, an

and how would you do the rods without cylinder offset?

Online PoorUB

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Re: modern crankshafts
« Reply #52 on: April 14, 2018, 04:55:21 AM »
Quote
er, added a forged plain bearing crank, an

and how would you do the rods without cylinder offset?

You don't!
I am an adult?? When did that happen, and how do I make it stop?!

Offline flh canuck

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Re: modern crankshafts
« Reply #53 on: April 14, 2018, 09:02:07 AM »
I've probably racked up a few hundred thousand miles on Harley big twins over the past 25 years.

Have never experienced a bottom end failure or any kind of mechanical failure for that matter in all those miles. Seems to me that they put together a pretty good motorcycle for the most part. Good dealer network and even better aftermarket support that no other manufacturer could ever hope to achieve.

My most recent purchase is a 2018 Ultra Limited. I like the twin-cooled design of the heads which as already stated, provides cooling in the area where it is most needed. I am all for changes that improve the design without changing the basic character of the engine.

I like the fact that the engine remains 45 degrees with push rods and roller bearing crank. Then again, I also like old John Deere tractors, Model T Fords and old radial engine aircraft. Simple technology, designed to be serviced and many of those old machines are still running just fine today. Plenty of other choices out there for folks that want the latest and greatest technology but Harley is smart to stick with a proven design that sets them apart from all the other manufacturers.

Just my humble opinion...  :chop:

2018 Ultra Limited. Back in black!

Offline Beave

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Re: modern crankshafts
« Reply #54 on: April 14, 2018, 09:08:59 AM »
Offset cylinders would change the feel of the motor, and is a fundamental design aspect that sets Harley apart from any other manufacturer.  Every model Harley has offered with increased suspension travel has failed to sell.  I don't see any business case for a long suspension bagger.  It didn't save Victory.  Half the buyers pick the lowered models and don't seem to care about a lousy two inches of travel.  Crank runout is a non issue with most most buyers as they do not modify them.  Hell, Ive got one of those 0.007" TIR cranks with 235,000 miles and zero crank related issues, but its still an 88. I would never know or care if I hadn't measured it.   
With speed comes stability.

Offline JW113

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Re: modern crankshafts
« Reply #55 on: April 14, 2018, 09:28:54 AM »
Yes, I'm also lost on the "crankshaft with better reliability" point. I've been riding these things for decades, and if there has been one thing that has never failed, it's the bottom end. At least on any of the bike's I've owned. And that is not from lack of trying. I've pegged the rev limiter (set at 7500) on my 113 many times. Still holding in there just fine.

There is no question that with the introduction of the twin cam, and the press together crankshaft, there were problems. All of which were related to design tolerance and manufacturing process, and none of which plain bearings would have solved. It appears that they have that under control now, but that said, I have a crank made in 2006 that has .001" runout, and has not budged in over 50,000 miles. It all depends on who made the crank. But with a chain cam drive, who's to say that .007" runout is a bad thing, as long as it doesn't move?

Suspension travel... all depends how high off the ground you want to sit on it, right? Most folks like a lower riding bike, in fact that is often a big "feature". They even name some models "Low Rider".

At the end of the day, there are those that will never be satisfied with what rolls off the showroom from. I am certainly in that camp, and in fact I have a lot of fun tailoring the showroom bike to "my" bike.

Don't you?

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Online PoorUB

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Re: modern crankshafts
« Reply #56 on: April 14, 2018, 12:26:41 PM »
and in fact I have a lot of fun tailoring the showroom bike to "my" bike.

Don't you?

-JW

No I don't, I would prefer to buy a motorcycle that I don't have to drop $2,000-$3,000 more into it to make it ride decent, and have reasonable power.

I am seriously considering the 2018 Gold Wing, or the BMW K1600 for my next ride. Either way I might hang on to my Harley for those lazy Sunday rides and have the Honda or the BMW for touring.
I am an adult?? When did that happen, and how do I make it stop?!

Offline JW113

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Re: modern crankshafts
« Reply #57 on: April 14, 2018, 02:15:54 PM »
For sure, Harley-Davidsons are not for everybody. Good luck with the new bike, though.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Offline Deye76

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Re: modern crankshafts
« Reply #58 on: April 15, 2018, 05:32:29 AM »
I've been good with Harley for many years. Still am. Agree with JW113, for the most part the bottom ends do just fine until we push the power limits they were designed for. As for suspension, all I hear is travel. The truth is travel is only part of the equation, you need rebound and damping too. As the roads gets worse, and they are, factory suspension may not be adequate for some. But we have the after market and there are choices. As for Goldwings and Beemers, go on their tech sites, not all is "hunky-dory". Me, I have no need to hit 10,000 rpm, and I have no illusions of granduer trying to make a road racer out of a bagger. Comparing other brands to Harley is just apples & oranges. Pick your poison.
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Offline borno

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Re: modern crankshafts
« Reply #59 on: April 15, 2018, 07:08:24 AM »
A harley crank is a thing of beauty (after it comes back from Darkhorse)  :up:

Offline sbcharlie

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Re: modern crankshafts
« Reply #60 on: April 16, 2018, 04:54:03 AM »
wow things sure get twisted on this forum  first I thought this was a tech forum. I was just letting you guys know what other manufactures are doing on crankshafts, like pressed pin crankshafts. if  Harley saw the need they could do this. I remember when they removed the top bushing in the con-rod you guys thought the sky was falling...  another fact I have never seen so many crankshafts replaced like on a twin cam. dark horse has made a great business rebuilding these things  sbc

Offline 1FSTRK

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Re: modern crankshafts
« Reply #61 on: April 16, 2018, 05:10:03 AM »
wow things sure get twisted on this forum  first I thought this was a tech forum. I was just letting you guys know what other manufactures are doing on crankshafts, like pressed pin crankshafts. if  Harley saw the need they could do this. I remember when they removed the top bushing in the con-rod you guys thought the sky was falling...  another fact I have never seen so many crankshafts replaced like on a twin cam. dark horse has made a great business rebuilding these things  sbc

we had an engineer at shop yesterday for KTM. he brought up something interesting about crankshafts. it seems that the metric manufactures are going away from roller bearing rod assembly . reason there not much surface area on a roller pin  bearing. these modern engine now are getting into the 13.5 plus compression ratio and rods are going bad. so there using a plain type bearing in there engines. one thing I'm learning about the M-8 they like a lot of compression  interesting if you  sit and ponder what going on in modern engines. sbc

OK let us get technical then, are you/they saying that 13.5 static compression is the tipping point?

Are you implying that the cylinder pressure from high static comp ratios over load the roller bearings?

If  so wouldn't the cam timing and actual CCP be a better indicator?

And last but not least are you saying the compression loads are greater than the combustion loads on the crank and rod bearings?

« Last Edit: April 16, 2018, 05:23:37 AM by 1FSTRK »
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Offline sbcharlie

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Re: modern crankshafts
« Reply #62 on: April 16, 2018, 05:53:30 AM »
what ever, you one narrow minded guy on this forum that really annoys me. just wanted people to see what other manufactures are doing. Harley not going to change anything. I could really careless

Offline 1FSTRK

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Re: modern crankshafts
« Reply #63 on: April 16, 2018, 06:08:54 AM »
what ever, you one narrow minded guy on this forum that really annoys me. just wanted people to see what other manufactures are doing. Harley not going to change anything. I could really careless

I am sorry to hear that, I saw the word modern and followed the thread hoping to learn something new. The difference between videos and a real tech forum like we have is people here can ask tech questions and expect technical, logical answers to back claims and marketing. Sometimes we learn something new, sometimes we learn something is being presented as new or better but we always learn.
"Never hang on to a mistake just because you spent time or money making it."

Offline sbcharlie

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Re: modern crankshafts
« Reply #64 on: April 16, 2018, 07:23:22 AM »
I glad you watch my utubes, I have some new about completed showing M-8 head magic, and using a electronic velocity probe
better yet you should take my safety porting class and learn how to make fast Harleys   sbc

Offline hogpipes1

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Re: modern crankshafts
« Reply #65 on: April 17, 2018, 09:35:00 PM »
I've probably racked up a few hundred thousand miles on Harley big twins over the past 25 years.

Have never experienced a bottom end failure or any kind of mechanical failure for that matter in all those miles. Seems to me that they put together a pretty good motorcycle for the most part. Good dealer network and even better aftermarket support that no other manufacturer could ever hope to achieve.

My most recent purchase is a 2018 Ultra Limited. I like the twin-cooled design of the heads which as already stated, provides cooling in the area where it is most needed. I am all for changes that improve the design without changing the basic character of the engine.

I like the fact that the engine remains 45 degrees with push rods and roller bearing crank. Then again, I also like old John Deere tractors, Model T Fords and old radial engine aircraft. Simple technology, designed to be serviced and many of those old machines are still running just fine today. Plenty of other choices out there for folks that want the latest and greatest technology but Harley is smart to stick with a proven design that sets them apart from all the other manufacturers.

Just my humble opinion...  :chop:

Sounds like the same kind of beer i like . :up: