Piston size question.
Road Warrior
Joined: Sep 2015
Posts: 1,447
Likes: 463
From: USA
Not really clear on just what you want to accomplish on your engine but, if you read the requirement specs on the piton set you show in your first post might answer some oh your questions. It states, this piston set should only be used with a big bore set of jugs. If thats what you have, your good to use whatever oversize piston set for the 1550 you wish. That is providing the cylinder wall bore cleans up within that spec oversize piston set. Like mentioned, it could be at, .010, .020, .030. Much beyond that, its both a matter of if theres even a larger oversized available and the question of the barrel thickness a consideration. Your engine manufacturers provide for their parts producers exact specifications on the max bore recommended. In my shop we used Federa Mogul provided text information.
Outstanding HDF Member
Joined: Dec 2008
Posts: 2,007
Likes: 353
From: Ohio
3.875 cylinder oversized 0.010.
Road Captain
Joined: Jun 2012
Posts: 574
Likes: 156
From: Big Sky Country
Yes. Not sure why all the confusion and obfuscation on this point.
Road Warrior
Joined: Aug 2015
Posts: 1,712
Likes: 410
From: Puyallup, WA
OP - The kit you are looking at is for a 1550cc motor (95 ci) bored 10 over stock bore size of 3 7/8". An overbore kit, is designed for when your cylinders get worn and you want essentially keep the stock motor size; you bore 10 over and use an overbore kit, such as the one you showed. The bore needed for this kit would be 3 7/8" (3.875) + .010" = 3.885". And yes, a 95 can easily be bored 10 over.
Boring a motor to a larger displacement, is a whole 'nother deal. If you want to increase displacement, bore the cylinders out. A 95ci motor is a TC88 bored from 3 3/4" to 3 7/8".
Your post says "if I were to have my 88" cylinders bored would it make a difference?" If you are looking at a 1550 kit, that is for a 1550cc of 95 ci motor, a TC88 is 88ci or 1450cc; not a TC88.
Figure out what you have, what you want, and go from there. Several other good posts about matching pistons to cylinders.
Boring a motor to a larger displacement, is a whole 'nother deal. If you want to increase displacement, bore the cylinders out. A 95ci motor is a TC88 bored from 3 3/4" to 3 7/8".
Your post says "if I were to have my 88" cylinders bored would it make a difference?" If you are looking at a 1550 kit, that is for a 1550cc of 95 ci motor, a TC88 is 88ci or 1450cc; not a TC88.
Figure out what you have, what you want, and go from there. Several other good posts about matching pistons to cylinders.
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Tourer
Joined: May 2017
Posts: 289
Likes: 13
From: Buell Town
OP - The kit you are looking at is for a 1550cc motor (95 ci) bored 10 over stock bore size of 3 7/8". An overbore kit, is designed for when your cylinders get worn and you want essentially keep the stock motor size; you bore 10 over and use an overbore kit, such as the one you showed. The bore needed for this kit would be 3 7/8" (3.875) + .010" = 3.885". And yes, a 95 can easily be bored 10 over.
Boring a motor to a larger displacement, is a whole 'nother deal. If you want to increase displacement, bore the cylinders out. A 95ci motor is a TC88 bored from 3 3/4" to 3 7/8".
Your post says "if I were to have my 88" cylinders bored would it make a difference?" If you are looking at a 1550 kit, that is for a 1550cc of 95 ci motor, a TC88 is 88ci or 1450cc; not a TC88.
Figure out what you have, what you want, and go from there. Several other good posts about matching pistons to cylinders.
Boring a motor to a larger displacement, is a whole 'nother deal. If you want to increase displacement, bore the cylinders out. A 95ci motor is a TC88 bored from 3 3/4" to 3 7/8".
Your post says "if I were to have my 88" cylinders bored would it make a difference?" If you are looking at a 1550 kit, that is for a 1550cc of 95 ci motor, a TC88 is 88ci or 1450cc; not a TC88.
Figure out what you have, what you want, and go from there. Several other good posts about matching pistons to cylinders.
OK. I have a stock 88". These .010 over pistons were going to be used in a different 95" (high mileage bike, so I'm guessing for worn cylinders as you speak of). They were never used and was told I could have them. So, if my 3.750 88" stock jugs could be bored to 3.885 (not 3.875) I could have a 95" for the cost of a cylinder bore.
Road Warrior
Joined: Aug 2015
Posts: 1,712
Likes: 410
From: Puyallup, WA
OK. I have a stock 88". These .010 over pistons were going to be used in a different 95" (high mileage bike, so I'm guessing for worn cylinders as you speak of). They were never used and was told I could have them. So, if my 3.750 88" stock jugs could be bored to 3.885 (not 3.875) I could have a 95" for the cost of a cylinder bore.
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Tourer
Joined: May 2017
Posts: 289
Likes: 13
From: Buell Town
Yes. That seems to be the best choice. Thanks everyone for taking the time to voice your knowledge on the subject. My (non-machinists) logic thinks that if the cylinders that I have are capable of being bored from 3.750 to 3.9375 then they should be fine to be bored from 3.750 to 3.885... we'll see Monday.
Thread Starter
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Tourer
Joined: May 2017
Posts: 289
Likes: 13
From: Buell Town
Yes. That seems to be the best choice. Thanks everyone for taking the time to voice your knowledge on the subject. My (non-machinists) logic thinks that if the cylinders that I have are capable of being bored from 3.750 to 3.9375 then they should be fine to be bored from 3.750 to 3.885... we'll see Monday.
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