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Air Medal or two
Join Date: Jul 2003
Location: cross roads
Posts: 14,079
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Harley evolution piston rings
Q. - I had a leaky head gaskt, tore dwn replacing cylinder studs, dual pluging, 530 cam and what not...it is a Low mileage engine . Cylinders and rings great shape (except the old cylinder studs)
The BIG Q. - Piston and rings cylinder PURRFECT, replace the rings or not? The rings are still on the pistons.....
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D troop 3/5 Air Cav,( Bastard CAV) and 162 Assult Helicopter Co- (Vultures) South of Saigon, U Minh Forest, Delta, and all parts in between |
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04-10-2014, 03:57 PM
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Posts: 920
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i dont think I would if the mileage is low.
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04-10-2014, 04:07 PM
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Registered
Join Date: Feb 2010
Posts: 920
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how many miles was on it
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04-10-2014, 04:08 PM
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Eva
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Sell.
Buy Ducati.
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'78 SC Targa ~Brynhild~ Insta: @911saucy "The car has been the cave wall on which Industrial Man has painted his longings and desires." -Eddie Alterman- |
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04-10-2014, 04:09 PM
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Air Medal or two
Join Date: Jul 2003
Location: cross roads
Posts: 14,079
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Sell? Really ? Common, lets have a mature conversation.
you do not have to like a Harley.However i respect a Ducati ! Would the old rings reseat despite being disturbed to a new location? (on piston as in not quite same spot) Maybe 5000 miles on rebuild....they forgot cylinder studs.....hence the leaky head gaskts
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D troop 3/5 Air Cav,( Bastard CAV) and 162 Assult Helicopter Co- (Vultures) South of Saigon, U Minh Forest, Delta, and all parts in between |
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04-10-2014, 04:19 PM
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Registered
Join Date: May 2010
Location: atlanta
Posts: 1,979
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What is the typical lifespan of of the cylinder walls and piston rings on that engine?
I don't have much harley experience but if that were a ducati i would absolutely leave them in place. |
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04-10-2014, 05:08 PM
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Eva
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Mature convo:
Leave well enough alone and button it back up without doing the rings 
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'78 SC Targa ~Brynhild~ Insta: @911saucy "The car has been the cave wall on which Industrial Man has painted his longings and desires." -Eddie Alterman- |
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04-10-2014, 05:15 PM
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with only 5K miles on them I'd put it back together as is.
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04-10-2014, 05:33 PM
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Parrothead member
Join Date: Jul 2003
Location: Monmouth county, NJ USA
Posts: 13,832
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After today, I wont give advice on engine rebuilds....
Seriously though, I'd probably replace the rings and take a quick hone to the cylinder. I know that's nothing in terms of mileage, but I would just be concerned about the rings reseating properly. .
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Vinny Red '86 944, 05 Ford Super Duty Dually '02 Ram 3500 Diesel 4x4 Dually, '07Jeep Wrangler '62 Mercury Meteor '90 Harley 1200 XL "Live your Life in such a way that the Westboro Baptist Church will want to picket your funeral." |
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04-10-2014, 06:16 PM
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Registered
Join Date: Mar 2004
Location: Higgs Field
Posts: 22,603
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Once they have gotten to "know" one another, don't do anything to disturb their relationship. Just button it back up. You'll get well over 100,000 miles on a set, so with their currently low mileage, you would be gaining very little, percentage wise, in piston and cylinder life.
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Jeff '72 911T 3.0 MFI '93 Ducati 900 Super Sport "God invented whiskey so the Irish wouldn't rule the world" |
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04-10-2014, 08:50 PM
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Band.
Join Date: Dec 2003
Location: Denver, CO
Posts: 13,320
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Good lord, man! Is English your second language?
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04-10-2014, 10:23 PM
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Join Date: Feb 2008
Posts: 18,676
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What caused the rebuild and how many miles were on it? I heard the evolution/xb engines have weak cranks...
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dolor et pavor Copyright |
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04-10-2014, 11:38 PM
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Air Medal or two
Join Date: Jul 2003
Location: cross roads
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Jeff - ( nice to hear from ya ) I have never tried to reuse piston rings....My biggest question, - Does the cylinder piston ring relationship care where the gaps land? (I know not to put the gap over the pin )
BUT there is no way i can put them back exactly where they were. AZ_porschekid - Someone rebuilt it ( Harley go figure ) and forgot the cylinder studs were "old". The elasticity is gone...typical of head bolts and studs in engines. Jeff How is the XXX Burger shop there? is it in Issaquah, Redmond? been awhile...
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D troop 3/5 Air Cav,( Bastard CAV) and 162 Assult Helicopter Co- (Vultures) South of Saigon, U Minh Forest, Delta, and all parts in between |
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04-11-2014, 02:20 AM
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Parrothead member
Join Date: Jul 2003
Location: Monmouth county, NJ USA
Posts: 13,832
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The gap orientation would be my main concern. The rings take a set in their current position. Once they are turned, they will have to reseat. Will they? yeah, most likely, and you probably wouldnt have any problems. But for the price of a set of rings , me personaly id change them. Any time I've pulled my Harleys apart, I've put new rings in.
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Vinny Red '86 944, 05 Ford Super Duty Dually '02 Ram 3500 Diesel 4x4 Dually, '07Jeep Wrangler '62 Mercury Meteor '90 Harley 1200 XL "Live your Life in such a way that the Westboro Baptist Church will want to picket your funeral." |
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04-11-2014, 02:46 AM
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Air Medal or two
Join Date: Jul 2003
Location: cross roads
Posts: 14,079
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On two strokes the rumor is the rings float . Some have a pin at the ring gap to prevent this...i took my Porsche apart....and either the P.O. or shop had installed ALL the gaps straight dwn....or they had all moved dwn in 30 years......is unknown..........I wonder if on a Harley if they wander around the piston much ?.....Seems everyone i have ever taken apart the gaps have not been where they should have been.............
If they do wander around the piston,. then i am sure they would be all right to reuse...
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D troop 3/5 Air Cav,( Bastard CAV) and 162 Assult Helicopter Co- (Vultures) South of Saigon, U Minh Forest, Delta, and all parts in between |
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04-11-2014, 03:06 AM
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Still Doin Time
Join Date: Nov 2004
Location: Nokesville, Va.
Posts: 8,225
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I'll chime is because there is significant reason to replace the pistons and rings at this stage. The whole idea of leaving well enough alone is a good one except in this case. Stock Harley pistons and rings are designed for quite operation and good ring seal for the mass market. Unfortunately this does not lend it self well to a high(er) performance engine. The stock pistons and rings create a lot of frictional drag in the bore.
When you increase cam lift, spring pressure and RPM's on that EVO cylinder/head "sandwich" the cylinders tend to "lift" with heat, piston/ring drag. Ask me how I know. On an engine of that size the frictional loss of horsepower is a lot more than you would think with the stock pistons/rings. Buy a good set of aftermarket performance pistons (short skirts) that accommodate narrow and less tensioned rings. Keith Black as well as others make a good street performance low-drag piston/ring combo that still provides reasonable noise limits as well as good sealing characteristics. Last I checked the price point was very moderate. Also keep in mind that you may want to bump (slightly) the static compression ratio when replacing the pistons as I believe the stock is something like 8.5:1 to 9:1. You will see huge improvement by going up a full point in static compression. Lastly, since the rings and pistons are already out of the bore you have 'lost' the rings locations within the cylinders. So you now must hone and replace at least the rings. Final note too...................you should check the assembled deck height with base gasket, new pistons (only) installed and then use two of the stud nuts and torque them to 30 Ft lbs. Measure your deck height. You should shoot for something close to "0" as the head gaskets are very thick. There are several companies that sell varying thickness cylinder base gaskets. If you cannot find one thin enough you should have the bottom of the cylinders machined. Any good machine shop can do this.
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'15 Dodge - 'Dango R/T Hauls groceries and Kinda Hauls *ss '07 Jeep SRT-8 - Hauls groceries and Hauls *ss Sold '85 Guards Red Targa - Almost finished after 17 years '95 Road King w/117ci - No time to ride, see above '77 Sportster Pro-Street Drag Bike w/93ci - Sold Last edited by asphaltgambler; 04-11-2014 at 04:52 AM.. |
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04-11-2014, 04:44 AM
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Registered
Join Date: Feb 2010
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I stand corrected.
I have to change my opinion and agree with asphaltgambler He knows Harleys. In fact he helped me when I had problems with mine So I'd trust his advice |
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04-11-2014, 05:23 AM
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Still Doin Time
Join Date: Nov 2004
Location: Nokesville, Va.
Posts: 8,225
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To clarify afterburn's question if the pistons and cylinders had been removed as unit carefully and not rotated he could reuse. But he has already taken those apart.
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'15 Dodge - 'Dango R/T Hauls groceries and Kinda Hauls *ss '07 Jeep SRT-8 - Hauls groceries and Hauls *ss Sold '85 Guards Red Targa - Almost finished after 17 years '95 Road King w/117ci - No time to ride, see above '77 Sportster Pro-Street Drag Bike w/93ci - Sold |
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04-11-2014, 05:26 AM
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Eva
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I know DRAMATICALLY LESS about H-Ds than the Gambler,...
Like I said, replace those rings!
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'78 SC Targa ~Brynhild~ Insta: @911saucy "The car has been the cave wall on which Industrial Man has painted his longings and desires." -Eddie Alterman- |
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04-11-2014, 08:06 AM
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Air Medal or two
Join Date: Jul 2003
Location: cross roads
Posts: 14,079
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This forum is great wealth of info !
I am having .050 shaved off the heads, Double plugged, and probably no base gaskt. ( just 3 bond) A touring cam shaft of sorts (little more lift little more duration ) Should be about 9.5 to 1 CR i hope I can go other pistons.Never thought about it.......just a tour bike with a little more pep i hope!
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D troop 3/5 Air Cav,( Bastard CAV) and 162 Assult Helicopter Co- (Vultures) South of Saigon, U Minh Forest, Delta, and all parts in between |
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04-11-2014, 06:27 PM
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Eva
Das Eos-Gone But Not Forgotten...
Battle Wagon
