simple top end rebuild
Thread Starter
|
Ultimate HDF Member
Joined: Mar 2007
Posts: 6,112
Likes: 20
simple top end rebuild
Problem guy's,friend of mine has a twincam thats using a qt. of oil every 2000 miles,he really short on cash so I've told him to go 95 like so many here suggest.He believe's he can simply measure cylinder runout and stick oversize ring's in it and do the heads.I'm not a fan of doing rings only but it is what it is,so how much over can he safely run oversize ring's?It's a stock 03 88"with 72000 on it.Thanks for any advice and thanks again for the help last yr.
Stellar HDF Member
Joined: Aug 2012
Posts: 2,664
Likes: 184
From: Indiana, USA
Cylinders are 300 a pair new or $100 pair new take offs shipped to your door from ebay. IMO- the cheapest fix is to purchase a used set of new take offs from ebay and re ring what you have and replace the valve seals while you are in there. You might even find a set of standard bore cylinders, pistons and rings all with 1 mile or less from a dealer that has installed a big bore kit in a new bike before delivery. Again these are all over ebay for next to nothing.
If that is not an option, be sure to measure what you have before putting it back together. Usually when you go oversize rings you have over size bored the cylinders first. High mileage wear in the cylinders could generate taper between the top and bottom and if you have significant wear in the top you usually have a ridge at the top of the cylinder wall. If you go oversize rings without boring or removing the ridge, the ridge can damage the top ring. Having said all of that, I have seen 50k mile cylinders that still have the hone marks on the cylinder walls...
Ist thing is to pull it down and look at what you have, and if possible measur ethe bore several locations top to bottom. Next take your fingernail and see if you can feel a raised dge at the top of the cylinder bore. The raised edge is the original bore, the lower larger bore is the wear. Assuming no to negligable wear, standard rings will be better than what he had before but without a bore not as good as new.
Next look at the valve guides. A new gasket kit comes with guide seals. Again assuming negligable wear and no sloppy valve guides, replacing the seals will get it back to where it was without the oil consumption.
If that is not an option, be sure to measure what you have before putting it back together. Usually when you go oversize rings you have over size bored the cylinders first. High mileage wear in the cylinders could generate taper between the top and bottom and if you have significant wear in the top you usually have a ridge at the top of the cylinder wall. If you go oversize rings without boring or removing the ridge, the ridge can damage the top ring. Having said all of that, I have seen 50k mile cylinders that still have the hone marks on the cylinder walls...
Ist thing is to pull it down and look at what you have, and if possible measur ethe bore several locations top to bottom. Next take your fingernail and see if you can feel a raised dge at the top of the cylinder bore. The raised edge is the original bore, the lower larger bore is the wear. Assuming no to negligable wear, standard rings will be better than what he had before but without a bore not as good as new.
Next look at the valve guides. A new gasket kit comes with guide seals. Again assuming negligable wear and no sloppy valve guides, replacing the seals will get it back to where it was without the oil consumption.
Road Master
Joined: Jul 2005
Posts: 1,061
Likes: 5
From: Fort Worth TX
As we all know that a correction would be to bore and hone the cylinders replace the pistons.
With a cylinder that has been run that long the re ring deal is a short term fix at best. I would think by the time you hone to get the cylinder straight the piston to wall would be larger than desired.
Money being tight a set of 95 inch se flat tops would be a very simple route.. Company's like Drag no sell a very low dollar 95 inch cast piston. Myself have no first hand dealing with it. But maybe the local shop that you are near has.
I have a set of JE forged 10.5 pistons that where run less than 4000 miles. Brand new ring kit with it. Free for the guy pay the shipping. When you bore and hone have the machine shop remove the dome and turn it into a flat top if you are running stock cams.
With a cylinder that has been run that long the re ring deal is a short term fix at best. I would think by the time you hone to get the cylinder straight the piston to wall would be larger than desired.
Money being tight a set of 95 inch se flat tops would be a very simple route.. Company's like Drag no sell a very low dollar 95 inch cast piston. Myself have no first hand dealing with it. But maybe the local shop that you are near has.
I have a set of JE forged 10.5 pistons that where run less than 4000 miles. Brand new ring kit with it. Free for the guy pay the shipping. When you bore and hone have the machine shop remove the dome and turn it into a flat top if you are running stock cams.
Last edited by HDWRENCH; Jan 29, 2015 at 08:36 AM.
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,091
Likes: 7,611
From: Poolville
for what motor?
I am interested in the piston for what motor will they fit. Bore size...
As we all know that a correction would be to bore and hone the cylinders replace the pistons.
With a cylinder that has been run that long the re ring deal is a short term fix at best. I would think by the time you hone to get the cylinder straight the piston to wall would be larger than desired.
Money being tight a set of 95 inch se flat tops would be a very simple route.. Company's like Drag no sell a very low dollar 95 inch cast piston. Myself have no first hand dealing with it. But maybe the local shop that you are near has.
I have a set of JE forged 10.5 pistons that where run less than 4000 miles. Brand new ring kit with it. Free for the guy pay the shipping. When you bore and hone have the machine shop remove the dome and turn it into a flat top if you are running stock cams.
With a cylinder that has been run that long the re ring deal is a short term fix at best. I would think by the time you hone to get the cylinder straight the piston to wall would be larger than desired.
Money being tight a set of 95 inch se flat tops would be a very simple route.. Company's like Drag no sell a very low dollar 95 inch cast piston. Myself have no first hand dealing with it. But maybe the local shop that you are near has.
I have a set of JE forged 10.5 pistons that where run less than 4000 miles. Brand new ring kit with it. Free for the guy pay the shipping. When you bore and hone have the machine shop remove the dome and turn it into a flat top if you are running stock cams.
HDF Community Team
Joined: Jun 2006
Posts: 12,774
Likes: 2,606
From: san antonio
Problem guy's,friend of mine has a twincam thats using a qt. of oil every 2000 miles,he really short on cash so I've told him to go 95 like so many here suggest.He believe's he can simply measure cylinder runout and stick oversize ring's in it and do the heads.I'm not a fan of doing rings only but it is what it is,so how much over can he safely run oversize ring's?It's a stock 03 88"with 72000 on it.Thanks for any advice and thanks again for the help last yr.
No O/S rings please, stock bore/piston, stock rings. I have a set 88" cylinders and pistons already in a box that the guy can have for $200, plus shipping. Less than 5K miles before big bore kit was installed. No scuffing on pistons, cross hatch marks still visible, a little carbon on piston tops. Much better place to start than cylinder and pistons with $72K miles of wear. PM me if interested.
Sponsor
Joined: Dec 2007
Posts: 12,084
Likes: 829
Who the hell know's IF the bore is bad.
My Magic 8 Ball here, can't answer that.....not w/o setting up a dial bore guage.
Poor guy doesn't have a lot of money, hone/re-ring, quick valve job/seals and that'll run fine until he can come up with some dough to bore IF NEED BE.
Scott
My Magic 8 Ball here, can't answer that.....not w/o setting up a dial bore guage.
Poor guy doesn't have a lot of money, hone/re-ring, quick valve job/seals and that'll run fine until he can come up with some dough to bore IF NEED BE.
Scott
Trending Topics
HDF Community Team
Joined: Jun 2006
Posts: 12,774
Likes: 2,606
From: san antonio
Who the hell know's IF the bore is bad. My Magic 8 Ball here, can't answer that.....not w/o setting up a dial bore guage.
Poor guy doesn't have a lot of money, hone/re-ring, quick valve job/seals and that'll run fine until he can come up with some dough to bore IF NEED BE.Scott
Poor guy doesn't have a lot of money, hone/re-ring, quick valve job/seals and that'll run fine until he can come up with some dough to bore IF NEED BE.Scott
Last edited by djl; Jan 29, 2015 at 02:06 PM.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Stellar HDF Member
Joined: Aug 2012
Posts: 2,664
Likes: 184
From: Indiana, USA
Good point, In my profession I have had access to gages most people do not. And I have to admit that I have pulled 1 down when I was not so well off, did not measure anything, ridge reamed the top of the cylinder, bush honed the walls to cross hatch, replaced the valve stem seals and put it back together with new stock rings and gaskets.
Any of his buddies rebuilding SB Chevies should have a ridge reamer and bush hone...
Any of his buddies rebuilding SB Chevies should have a ridge reamer and bush hone...
Thread Starter
|
Ultimate HDF Member
Joined: Mar 2007
Posts: 6,112
Likes: 20
Update kinda,just got a call from another friend who heard about whats going on and is sending a set of cylinders from a 96" that has 1700 miles on them,says cross hatch looks like they never been run.Opens up another question though,how much clearance do the pistons need?And should I still run a hone through them?Thanks djl.for the offer but he's flat and these cylinders hopefully will work.Thanks everyone for the help.