Piston size question.
Seasoned HDF Member
Joined: Mar 2008
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From: Central Texas
I bought my pistons first, and the machine shop miked my pistons, and then bored my jugs to match, sixty thousand miles and counting says it was a good plan.
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Joined: May 2018
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From: Viet Vet, crossroads
Carry on and do it any way you want.
Road Warrior
Joined: Sep 2015
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From: USA
Having punched (machine bored) many engine bores over the years, your call is the wisest. Until the machining is completed there can be cases where the boring step will not clean up the cylinder walls at the desired oversize,for the already purchased piston.
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Joined: May 2018
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From: Viet Vet, crossroads
It would be quite embarrassingly expensive to send over your ceramic coated, molly skirted, firewalled, balanced stuff and have the shop say
go get a bigger set!
The wallet would feel embarrassed!!
go get a bigger set!
The wallet would feel embarrassed!!
Seasoned HDF Member
Joined: Mar 2008
Posts: 9,384
Likes: 1,776
From: Central Texas
Well I finally get what you are saying, and it would be crazy to bore a jug and then not have enough meat left to clean up the jug after the bore, and have to buy new pistons and jugs as well.
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Joined: May 2018
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From: Viet Vet, crossroads
Yup!
Most of the time there is several OS one can go too..
.If there is a big score/scatch then the bore could still be done-
Just bigger and a larger piston then one that was supposed to go in the fresh hole
Most of the time there is several OS one can go too..
.If there is a big score/scatch then the bore could still be done-
Just bigger and a larger piston then one that was supposed to go in the fresh hole
Thread Starter
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Tourer
Joined: May 2017
Posts: 289
Likes: 13
From: Buell Town
Last edited by 838; Jun 1, 2018 at 09:48 PM.
Banned
Joined: May 2018
Posts: 4,576
Likes: 978
From: Viet Vet, crossroads
The final answer is between you and your machine shop, or a machinest on here.
I would say no.
But I am not the resident expert.
I would say no.
But I am not the resident expert.
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Ultimate HDF Member
Joined: Mar 2012
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From: Santa Cruz
While measuring boresize is nessicary if you are trying to go with smaller oversizes, few folks are doing that. They want the biggest oversize for performance. Pretty much any 88/96/103 jug can be bored to 98/107 size. There must be some pretty serious bore damage to not clean up at that bore...or a way offset sleeve where the overbore would get into the cylinder. Both rare.
Last edited by 0ldhippie; Jun 1, 2018 at 11:01 PM.
Thread Starter
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Tourer
Joined: May 2017
Posts: 289
Likes: 13
From: Buell Town
While measuring boresize is nessicary if you are trying to go with smaller oversizes, few folks are doing that. They want the biggest oversize for performance. Pretty much any 88/96/103 jug can be bored to 98/107 size. There must be some pretty serious bore damage to not clean up at that bore...or a way offset sleeve where the overbore would get into the cylinder. Both rare.
So bore the cylinder with the specs of 3.885 to accommodate a 3.885 piston?
Last edited by 838; Jun 1, 2018 at 11:15 PM.