Author Topic: Cubes vs. Vibes  (Read 791 times)

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Offline JW113

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Cubes vs. Vibes
« on: August 25, 2017, 07:10:07 PM »
As the subject line says, for you guys that have installed stroker flywheels, what did it do to perceived vibration felt in the bars, seat, and boards/pegs? And I mean this for the rigid mounts, not FXR/FLTs.

When I changed the wheels in my Evo from 4-1/4 to 4-5/8, it definitely changed the nature of the vibration. My stock '77 FLH is still 74 cubes, and the vibes are no issue at all until you get it spun way up, which I don't. Like to keep it that way, but you know how it goes after a few cocktails and you start thinking about how nice it would be to have a little bit more power....
 :wink:

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

Offline packrat56

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Re: Cubes vs. Vibes
« Reply #1 on: August 25, 2017, 07:24:48 PM »
    I have a 5" stroke it's only bad for me at around 1500-2000 rpm. My right hand goes to sleep, but on the hwy going 55 on up its fine
Now I know, why some animals eat their young.

Offline crock

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Re: Cubes vs. Vibes
« Reply #2 on: August 25, 2017, 09:08:24 PM »
Had a 98" S&S sidewinder kit done last year. Have to say it's as smooth as the old 74" was
Crock

Offline tmwmoose

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Re: Cubes vs. Vibes
« Reply #3 on: August 26, 2017, 04:50:26 AM »
I put a set of 4 3/4" in my 84 Shovel 91" and was very impressed with the ride .The problems of ole shakers were from guys buying wheels only and slapping their stuff on them and lousy assembaly

Offline rigidthumper

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Re: Cubes vs. Vibes
« Reply #4 on: August 26, 2017, 04:59:50 AM »
My favorite was the 3 5/8 x 4 1/2, 93" build. S&S or T&O wheels, balanced, were as smooth ( or better) as any stocker, with much better acceleration.
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Offline a_disalvo

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Re: Cubes vs. Vibes
« Reply #5 on: August 26, 2017, 08:26:40 AM »
Got a  S&S 98" sidewinder, Crane 308B cam, BC Gerolomy dual plug heads, installed about 20 years ago, still running strong!! I remember talking to the builder about what type of riding I did- had something to do with the balance formula if i recall??? Bike runs smooth as glass after 60, not bad at lower MPH, 1979 FXS - FWIW, Frank

Offline 76shuvlinoff

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Re: Cubes vs. Vibes
« Reply #6 on: August 27, 2017, 03:57:12 AM »
The 93 has worked sweet for me since 2004 but I have to admit mine is  a full S&S long block.
 (they called it the 93HC back then)

Since this is not an H-D mill I have often fantasized about going apeshit with it, 106? 113? But the return on the cost of doing that to this old of technology doesn't work for my wallet. The same investment in the TC motor in my fatassed barge would probably net me more thrills or buy me a complete, running, throwaway crotch rocket.....

But we do what we do.   :wink:

Mark
« Last Edit: August 27, 2017, 04:14:51 AM by 76shuvlinoff »
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Offline crock

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Re: Cubes vs. Vibes
« Reply #7 on: August 27, 2017, 06:22:49 AM »
76 If you own a shovel it can't be about the money. After my build I have over 5 K in the motor. There are EVO bikes selling on Craig's list around here for 6. It's all about the love of the era of that motor. Read it on here somewhere " New enough that the MOCO had a lot of the bugs out but old enough to work on" . I say old enough to still have "style" . Definitely the last to not look like a Volkswagen motor
Crock

Offline Hossamania

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Re: Cubes vs. Vibes
« Reply #8 on: August 27, 2017, 08:53:16 AM »
A friend rebuilt a worn out 80" using S&S 93" stroker kit. Not surprisingly, the motor was much smoother than the original.
Unfortunately, he beat hell out of it right from the get go and at 4000 miles after complete bike frame up restoration, I wouldn't have given him $2500 for that thing. A story for another time.
Happiness does not buy money.

Offline turboprop

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Re: Cubes vs. Vibes
« Reply #9 on: August 27, 2017, 09:40:54 AM »
Shovel, Evo, Pan, TC-A, doesn't really make a difference as they are all basically the same root design. Felt vibration is all about the balance factor. Regardless of engine era, the balance factor of a 45 degree twin with a shared crankpin has a bandwidth of maybe 1k rpm. The center of range that it is in balance can be shifted right or left, but its still only 1k RPM wide.

Years ago I had a 4-" shovel with a lot invested in it. I forget the balance factor used, but at 70 mph the mirrors were very clear and felt vibration was minimal. At idle the front wheel would bounce around. My girlfriend at the time had a certain rpm that she really liked.
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Offline Burnout

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Re: Cubes vs. Vibes
« Reply #10 on: August 28, 2017, 10:38:17 AM »
Cubes have little to do with vibration, there is certainly a slight difference because of a difference in reciprocating weight and or piston speed.

However the larger determining factor is basic design, a V Twin is not a neutral/balanced/or self canceling design vibration wise. You can make slight changes by altering crank weights, however those changes will only affect certain RPM ranges. Attempting to "Balance" an intrinsically unbalanced design is a band aid, and has little bang for the buck improvement. Probably not worthwhile except in cases where it will be operated outside normal parameters for sustained periods

If you are worried about vibration, a Harley is not a brand to look at. An opposed cylinder or I-4 cylinder layout has a dramatically improved vibration characteristics by orders of magnitude (several?).
They don't call me Ironhead Rick just because I'm "hard headed"

Offline Hossamania

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Re: Cubes vs. Vibes
« Reply #11 on: August 28, 2017, 02:02:57 PM »
Or a nice I-6 (BMW K1600, cough, cough)
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Offline Burnout

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Re: Cubes vs. Vibes
« Reply #12 on: August 30, 2017, 09:18:40 PM »
Did you know that a GL1500 will wheelie without using the clutch?
They don't call me Ironhead Rick just because I'm "hard headed"

Offline crock

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Re: Cubes vs. Vibes
« Reply #13 on: August 31, 2017, 04:22:49 AM »
It's so ugly it's trying to get away from itself   :hyst:
Crock

Offline Hossamania

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Re: Cubes vs. Vibes
« Reply #14 on: August 31, 2017, 05:54:43 AM »
It's so ugly it's trying to get away from itself   :hyst:

That's funny!
Happiness does not buy money.

Offline JW113

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Re: Cubes vs. Vibes
« Reply #15 on: August 31, 2017, 06:09:45 PM »
>If you are worried about vibration, a Harley is not a brand to look at.

Worried is not the issue. I am well aware that Harley and other make V-twins have vibration, along with vertical twins. But there is a difference between acceptable vibration, and intolerable vibration. I've also notice on the HDs and Indian that I've owned, they all have different levels of vibration. Both in amplitude, and rpm range. I have built two stroker motors, and in both cases, the perceived vibration did not get better. In one case, drastically worse. Possibly the way that it was built/set up.

Since I got myself on the subject, I think it is kind of pointless to try and compare how a stroked motor may vibrate compared to stock one over the internet. I think the only real method to answer that is to ride one of each, and compare.

Anybody got a 93" shovel stroker they want to loan me for, oh say, a few months?
 :SM:
 :hyst:

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

Offline 76shuvlinoff

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Re: Cubes vs. Vibes
« Reply #16 on: August 31, 2017, 06:52:17 PM »
Quote
Anybody got a 93" shovel stroker they want to loan me for, oh say, a few months?

 Hmmmmm could work a deal against a mid/late 50s Chevy 4x4....  :wink:
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Offline thumper 823

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Re: Cubes vs. Vibes
« Reply #17 on: September 02, 2017, 09:57:09 AM »
I do not know anything and can prove most the time..
I have a set of S&S bob weights here and to their way of thinking
is this-
You can not get rid of the vibration but you can move it anywhere from up and dwn to more of a horizontal plane .
S&S recommends more moving more horizontal so as to not feel it in your butt and handlebars.
They are NOT the final word either!
"T & O"  used to swiss cheeze my wheels back in the day when Bonnie worked there. (holes everywhere in the wheels)
I would have to say what ever method they used in the 70s was my favorite.
They have changed since then .
Albeit I have not tried all the new and improved vendors that have come along since then, or even a "balance master approach ".
As with most everything, there is usually a better way tomorrow and lots have them have gone past.
Perhaps a Vendor like Dark Horse has a handle on it now...IDK
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Offline Snowyone

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Re: Cubes vs. Vibes
« Reply #18 on: September 02, 2017, 01:59:27 PM »
Started out on a brand new 80 wideglide that would shake your fillings out but not knowing anybetter rode it that way till it puked on my Dad.  Well the cure was they put a 30 over piston in one hole and then it was even worse.  Went through lots of Loctite keeping it together.  Sent it to Lake Shore HD and told them I wanted a 4 1/2" stroke stock bore motor.  Wow, then found that mirrors were used for looking behind and not just for my girl friend to ck her lipstick.  Rode it that way for 50k and then through fault of my own burnt a hole in a piston with a intake leak.  Found out I had 30 over pistons and a 4 3/4" stroke.  Well I went with stock size pistons and cylinders from S&S and still going strong 15k later.  Now on later model rigs I own.  Bought an 11 Fatboy Lo with the 96 and it was a pooch in the power department.  Tried cams, pipes, tune, and still a pooch coming off a 95" hot rod RG.  Reached deep in my pocket and had Dan Vance build me a 124" motor that made me keep the bike.  Don't feel any vibes till I get to 80mph and then minimal but don't spend much time there as it's not that comfortable with the traffic, wind, and the unpredictable.  I bought a 08 Crossbones a few years ago because it was such a good deal and told the wife it was to turn.  Well I love that bike and it didn't get turned.  It was also a 96 and after having that 124 built for the Fatboy I knew an upgrade was in it's future.  Not having near as much in my pockets I did a 107 kit for it with some head work and a reworked crank with updated rods from Darkhorse.  It is smoother and easier to ride and doesn't give a lot up to the 124 till it gets over 80 where the 124 shines.  I think both are very well balanced with minimal runout and the difference is minimal between the 4 3/8 and 4 1/2" cranks

Offline Burnout

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Re: Cubes vs. Vibes
« Reply #19 on: September 03, 2017, 08:11:32 AM »
You can't really compare the new short stroke motors (with no soul) to our old favorites.

More stroke equals more torque, sadly it also moves the reciprocating mass farther from the crank centerline, and that's going to shake.



Luv's me some torque! I'll never forget being passed by the fella's on their big bore strokers going up Kern River Canyon on the big run.
They don't call me Ironhead Rick just because I'm "hard headed"

Offline Scott P

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Re: Cubes vs. Vibes
« Reply #20 on: September 07, 2017, 04:16:29 AM »
Many 4 3/4" S&S cranks over the years.
Smoother than the OEM.
Shimming the engine, proper engine combination, and how it's tuned, are all factors.
Otto Knowbetter sez, "steer clear of chameleons."

Offline Burnout

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Re: Cubes vs. Vibes
« Reply #21 on: September 07, 2017, 02:49:35 PM »
I don't see any way a stroker motor can be anywhere near a smooth as a 74".

The 74" motors had massive flywheels to dampen vibrations.
Your grandma's sewing machine probably shook harder than a 74" HD
They don't call me Ironhead Rick just because I'm "hard headed"

Offline remington007

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Re: Cubes vs. Vibes
« Reply #22 on: September 07, 2017, 03:04:34 PM »
I don't see any way a stroker motor can be anywhere near a smooth as a 74".

The 74" motors had massive flywheels to dampen vibrations.
Your grandma's sewing machine probably shook harder than a 74" HD
That would depend on how well it was balanced from the get go. Shovels are like people they are all different.

Offline crock

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Re: Cubes vs. Vibes
« Reply #23 on: September 08, 2017, 04:38:37 AM »
Currently running 4 3/4 stroke and at least for me seems smoother than the stock 74 motor was.  And yeah it doesn't make sense :scratch:
Crock

Offline thumper 823

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Re: Cubes vs. Vibes
« Reply #24 on: September 08, 2017, 05:35:04 AM »
AFAIK like I said B4 there are a couple ways to balance the assembly so it all feels better.
Again,
  AFAIK,  the rotating mass of the twin can NOT be dynamically balanced like a tire or a flat 6 engine or even a V8.
Those items can be balanced.
Not the twin.
The vibration can be moved around the "clock" to make them more tolerable.

D Troop 3/5, - C/16 ,162AHC, Mekong delta.
Amateur engineering with bad math.

Offline Scott P

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Re: Cubes vs. Vibes
« Reply #25 on: September 08, 2017, 06:12:12 AM »
I don't see any way a stroker motor can be anywhere near a smooth as a 74".

The 74" motors had massive flywheels to dampen vibrations.
Your grandma's sewing machine probably shook harder than a 74" HD

Nonetheless true.
Built waaaaaaaaaaaaaaaaaay too many to say different.
Otto Knowbetter sez, "steer clear of chameleons."

Offline Snowyone

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Re: Cubes vs. Vibes
« Reply #26 on: October 30, 2017, 01:50:44 PM »
Awe, you should have tried the early 50's ELs at 61 CI.  Smoooooth

Offline Scott P

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Re: Cubes vs. Vibes
« Reply #27 on: October 31, 2017, 02:55:28 AM »
I put a set of 4 3/4" in my 84 Shovel 91" and was very impressed with the ride .The problems of ole shakers were from guys buying wheels only and slapping their stuff on them and lousy assembaly

Yep. :up:
Otto Knowbetter sez, "steer clear of chameleons."

Offline JW113

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Re: Cubes vs. Vibes
« Reply #28 on: November 02, 2017, 09:29:21 PM »
"Balancing" a 45deg V-twin. Yep, impossible, but as Thumper said, do it so the 'out of balance' is the least objectionable to the rider.

So there are various ways they do balancing, but the one I'm most familiar with is to put the wheels individually on a zero friction bearing rig, add the "balance factor" weight to the crank pin hole, and start drilling the flywheel until you can place it in any position and it stays where put.

This has me thinking. So why can't you do this with assembled flywheels, leave the pistons off, set the crank assembly up in frictionless V-blocks, and add weight to the piston pin holes in the rods for the balance factor? Then drill the wheels until it can be placed in any position without turning?

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

Offline rbabos

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Re: Cubes vs. Vibes
« Reply #29 on: November 03, 2017, 08:38:40 AM »
Awe, you should have tried the early 50's ELs at 61 CI.  Smoooooth
Yes. Had a 47 EL knuckle and a 52 pan EL. Both smooth engines.
Ron