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15th January 2020
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Senior Master Custom Bike Builder
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Join Date: Mar 2006
Location: Athens, GA
Posts: 5,452 Sportster/Buell Model: XLCH Sportster/Buell Year: 1962
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__________________
Ham, porkchops and bacon all come from the same magical animal?! That's crazy!
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15th January 2020
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Custom Bike Builder
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Join Date: Dec 2014
Location: Phoenix
Posts: 2,289 Sportster/Buell Model: xlch Sportster/Buell Year: 1964 Sportster/Buell Model #2: XLCH IR EFI Sportster/Buell Year #2: 1971 Other Motorcycle Model: BMW K1200RS Other Motorcycle Year: 2001
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Pehaps that is the one, I seem to remember a bit more detail. It would not surprise me if he had made a few attempts at getting the point of that conversation across. Either way this link gets the point across. Different scenerios need different applications to arrive at the same point.
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15th January 2020
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Chief Master Mechanic
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Join Date: Sep 2019
Posts: 455 Sportster/Buell Model: XLH Sportster/Buell Year: 1969 Other Motorcycle Model: 111 Ironhorse Outlaw Other Motorcycle Year: 2004
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Quote:
Originally Posted by thefrenchowl
Ric,
With maths like yours on post #5:
""900 standard bore is 3.0, 900 standard ring would be 3.005""
I wouldn't want to buy any engine that's been near you!!!!!!!!!!!!!!
Patrick
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Well Patrick I'm so upset. How about you educate me. A 900 HD Sportster has a standard bore of 3 inches. Tell me about rings, what do you know? Please tell me how a 3.00 ring in a 3.00 bore with the proper end gap would seal.
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15th January 2020
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Senior Master Custom Bike Builder
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Join Date: Jun 2008
Location: Cornelius, OR
Posts: 9,504
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Rings are not measured outside the bore. They are machined at a significantly larger diameter then cut so they have tension on the bore.
Many buy oversized rings and hand fit down, so it is easier to butt the ring ends.
Production rings are almost always on the small side (large gap) to prevent butting.
A small Ring end gap is not critical unless you are racing in a limited class against someone with a tighter gap, (splitting hairs) and can't run a total seal ring because of rules. Not sure a total seal ring works well on the street or in a dirty motor like an Ironhead.
Rings seal because compression pushes them down and pressure gets behind the ring and forces it out against the cylinder. This is why many race motor pistons are "gas ported". However I don't believe that works on the street.
__________________
Ryder Rick "I know right from wrong, but sometimes, wrong feels right"
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15th January 2020
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Chief Master Mechanic
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Join Date: Sep 2019
Posts: 455 Sportster/Buell Model: XLH Sportster/Buell Year: 1969 Other Motorcycle Model: 111 Ironhorse Outlaw Other Motorcycle Year: 2004
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Quote:
Originally Posted by ryder rick
Rings are not measured outside the bore. They are machined at a significantly larger diameter then cut so they have tension on the bore.
Many buy oversized rings and hand fit down, so it is easier to butt the ring ends.
Production rings are almost always on the small side (large gap) to prevent butting.
A small Ring end gap is not critical unless you are racing in a limited class against someone with a tighter gap, (splitting hairs) and can't run a total seal ring because of rules. Not sure a total seal ring works well on the street or in a dirty motor like an Ironhead.
Rings seal because compression pushes them down and pressure gets behind the ring and forces it out against the cylinder. This is why many race motor pistons are "gas ported". However I don't believe that works on the street.
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Nailed it.
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16th January 2020
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Senior Custom Bike Builder
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Join Date: Nov 2006
Posts: 2,990 Sportster/Buell Model: KHK Sportster/Buell Year: 1954 Sportster/Buell Model #2: IronHead XLH Sportster/Buell Year #2: 1978 Other Motorcycle Model: XLRTT Other Motorcycle Year: 1966
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What Rick said, Ric…
You cannot measure a ring outside the bore, ie a 3.005 diam ring could not possibly seal a 3" bore.
Or look at it another way: machine on a lathe a 3"005 ring, then cut the gap: When you fit it in a 3" cylinder, maybe three points on the ring will actually touch the cylinder… ie NO SEAL despite the spring effect…
A 3" ring is a bigger diameter ring, then cut, then compressed, then machined round at 3", then gapped… that's the only way you'll get more than 3 points touching the bore.
Same logic when you want to redo seriously your drum brakes linings on a lathe: insert shims between shoes and cam, then skim linings on lathe to your drum ID then remove shims and as soon as you touch the lever, all the points of your linings will touch the drum = maximum brake surface instantly…
Patrick
__________________
Flat Head Forever
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16th January 2020
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Chief Master Mechanic
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Join Date: Sep 2019
Posts: 455 Sportster/Buell Model: XLH Sportster/Buell Year: 1969 Other Motorcycle Model: 111 Ironhorse Outlaw Other Motorcycle Year: 2004
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I'm not on here to argue with folks. I ask a simple question. It's been answered thank you.
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16th January 2020
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XL FORUM TEAM MEMBER
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Join Date: Jan 2011
Posts: 2,260 Sportster/Buell Model: dragbike Sportster/Buell Year: 1960
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I'm the one who sold you the pistons . The information you seek is:
Hastings 6457-040 cast iron
Hastings 2C 6457-040 moly faced cast iron
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16th January 2020
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Chief Master Mechanic
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Join Date: Sep 2019
Posts: 455 Sportster/Buell Model: XLH Sportster/Buell Year: 1969 Other Motorcycle Model: 111 Ironhorse Outlaw Other Motorcycle Year: 2004
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Quote:
Originally Posted by mrmom9r
I'm the one who sold you the pistons . The information you seek is:
Hastings 6457-040 cast iron
Hastings 2C 6457-040 moly faced cast iron
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Thank you. The pistons and new cylinders with oil returns lowered are in local shop getting fitted. I ordered rings from BMI Karts they will arrive today. Not sure of brand or even if they have 3 piece oil ring. They were cheap so if there not Hastings rings they will go on the shelf and I'll order the ones you have identified.
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16th January 2020
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Senior Custom Bike Builder
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Join Date: Nov 2006
Posts: 2,990 Sportster/Buell Model: KHK Sportster/Buell Year: 1954 Sportster/Buell Model #2: IronHead XLH Sportster/Buell Year #2: 1978 Other Motorcycle Model: XLRTT Other Motorcycle Year: 1966
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All is well Ric, sounds like you know what you're doin'...
Patrick
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