Why don't newer big twins have the potato sound? - Page 2 - Harley Davidson Forums



General Harley Davidson Chat Forum to discuss general Harley Davidson issues, topics, and experiences.
Sponsored by: J&P Cycles

Why don't newer big twins have the potato sound?

Closed Thread
 
 
 
P
 
Thread Tools Search this Thread
  #11  
Old 11-19-2010, 04:10 AM
Tactical111's Avatar
Tactical111 Tactical111 is offline
Road Master
Join Date: Aug 2010
Location: SE Michigan
Posts: 1,130
Thanks: 0
Thanked 3 Times in 3 Posts
Default

One factor for a different sounding engine is the bore to stroke ratio. To get the bigger displacements HD increased the bore primarily. It was the long stroke that gives the old Shovels and Evos that "potato" sound. Also read recently in a "Hot Baggers" Mag article that any idle below 1000 rpm delivers a shock to the crank shaft as the slow turning engine tries to cycle and can damage the lower end. If I can find the exact quote/article I'll pass it on. Oh, another big factor I think is the stock exhaust on the newer Harley's. I had one pull up next to me at a red light a few years ago and I swear it sounded like a Honda; it was a sporty if I recall.
  #12  
Old 11-19-2010, 04:53 AM
dog155's Avatar
dog155 dog155 is offline
Extreme HDF Member
Join Date: Nov 2006
Location: Windham,Maine
Posts: 13,299
Thanks: 0
Thanked 7 Times in 7 Posts
Default

Much higher idle speed and EFI!!!
  #13  
Old 11-19-2010, 05:12 AM
AFHarley's Avatar
AFHarley AFHarley is offline
One Of The Regulars
Join Date: Oct 2010
Location: Panama City Beach
Posts: 163
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Doesn't really matter to me... Still sounds better than those rice burner bikes IMO!
  #14  
Old 11-19-2010, 05:25 AM
brenn's Avatar
brenn brenn is offline
Elite HDF Member
Join Date: Aug 2008
Location: Kentucky
Posts: 4,932
Thanks: 0
Thanked 3 Times in 2 Posts
Default

My 04 Softail has a carb and Samson Big Guns. It REALLY sounds like a Harley. In fact, I may get baffles to quiet it for riding to work. However, even the most stock-exahaust, EFI new from the showroom Harley still sounds enough like a Harley to be distinguishable from everything else by sound alone, as soon as you hear it. Honda and Yamaha and Victory may make bikes that look like a Harley from a distance, but you can tell them apart by sound before you can do it by looks.
  #15  
Old 11-19-2010, 05:37 AM
reddog8145's Avatar
reddog8145 reddog8145 is offline
Road Captain
Join Date: May 2009
Location: Mancheser UK
Posts: 597
Thanks: 0
Thanked 0 Times in 0 Posts
Default

It would appear that the loss of the potato is down to the 96 engine having an oil pump that requires higher rev's to make sure that the oil gets to where its needed. I must admit I miss the potato sound, the new bikes sound quite modern on tick over. Even changing pipes has little effect.
However we do need to move with the times, or buy an older bike.
  #16  
Old 11-19-2010, 05:42 AM
MNPGRider's Avatar
MNPGRider MNPGRider is offline
Ultimate HDF Member
Join Date: Jul 2007
Location: SW Minnesota
Posts: 6,257
Thanked 25 Times in 20 Posts
Default

I don't think anyone yet has the correct answer. Po-ta-to Po-ta-to is a three beat sound coming out of a two cylinder engine. Modern Harleys only have a tater tater sound.

The Potato Potato sound was produced by the old ignition, which fired both spark plugs at the same time, producing a "wasted" spark on each cylinder's exhaust stroke. Because there is a 405 degree difference in the stroke from the rear cylinder to the front on each revolution, when the rear cylinder fires on its compression stroke, the front exhaust valve is still open, unburned gases are ignited in the front exhaust by the "wasted" spark, causing the first beat of the potato sound. The modern ignition fires each plug separately at the proper time.

Add in the richer fuel mixture from a carb which loaded up the exhaust with unburned gases, and a slow idle, and that's why the old bikes had the classic sound we all loved.

Japanese bikes say "rice-a-ro-ni".

Last edited by MNPGRider; 11-21-2010 at 04:09 PM.
  #17  
Old 11-19-2010, 05:46 AM
sageone sageone is offline
New Member
Join Date: Oct 2010
Posts: 91
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Wouldn't revert to old technology just for the sound alone. Would need a better reason.
  #18  
Old 11-19-2010, 06:22 AM
Jonesee Jonesee is offline
Outstanding HDF Member
Join Date: Sep 2006
Location: Florida
Posts: 2,917
Thanked 46 Times in 25 Posts
Default

Quote:
Originally Posted by sageone View Post
Wouldn't revert to old technology just for the sound alone. Would need a better reason.

I wouldn't buy a new bike for technology alone. Different strokes for different folks. I will stick with my carbed bike.
  #19  
Old 11-19-2010, 06:49 AM
sageone sageone is offline
New Member
Join Date: Oct 2010
Posts: 91
Thanks: 0
Thanked 0 Times in 0 Posts
Default

This is true, much easier to work on that's for sure.
  #20  
Old 11-19-2010, 06:59 AM
DCLXVI DCLXVI is offline
Road Warrior
Join Date: Aug 2009
Location: Central FL
Posts: 1,566
Thanks: 0
Thanked 5 Times in 3 Posts
Default

Between the EFI, emissions and newer style ignition the sound has been changed. The new sound is simply " tater, tater, tater, tater.
 
 
 
P
Closed Thread

Related Topics
Thread Thread Starter Forum Replies Last Post
Potato..potato...question TracerBullet General Harley Davidson Chat 103 07-31-2014 09:49 PM
How to get the potato/potato sound Flhrhog Exhaust System Topics 13 05-15-2014 03:38 AM
Heritage owners with stage 1: What exchaust's do you have Pete6114 Softail Models 31 03-26-2012 08:10 AM
Need Advice for stage 1 upgrade ... dantoniov Softail Models 20 01-29-2009 08:46 PM
Night Rod special touring ? no more bob CooliosBandit VRSC Models 13 07-20-2007 11:29 PM


Tags
bad, big, cam, davidson, fire, fuel, harley, ignition, injected, lope, noise, potato, potatto, pottato, single, sound, sounds

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump


All times are GMT -5. The time now is 08:30 PM.