I know there are shops out there that will bore your cylinders, add new piston , take care of the ring end gap and through in a new cam for about 1K.... then you can go to any compression you want...

 

ok....
i seem to be confusing several people that are trying to help me, and im probably giving them a headache, so ill try to clear this up.

i-dont-know-harleys. what i do know is cars. there are similarities between the two, and vast differences. for example, i can scar my bores, run a hone with slightly bigger rings, and its not a big deal. apparently it is on 2 wheels.

from what has been explained to me, im understanding that pistons and jugs in a harley, are matched sets? this is bonkers to me.

i understand that to properly get the right size in a jug, it has to be put in torque plates and machined to the correct size, but even with that, its not preferred. what is preferred, again loosely putting 2 and 2 together, is to buy a "matched" piston and jug set, or, machine my jugs and buy pistons made to fit.

so if this is correct, i can see why the help you all are providing includes new pistons where as the concept was escaping me as to why for, since nothing is wrong with my pistons.

Furthermore, including the advice im getting offline, i do not want to go big bore. because of two main reasons
1. this bike has andrews 57h cams in it already and a power commander v tuner. if i change the displacement i will have to get it tuned for sure, but, i do not know if even doing that will hurt or hinder the cams i have in it already

2. when you up displacement, you have to reinforce or replace damn near everything. "go big bore!" ok, what about my lifters, rods, springs, valves, pushrods, bearings, injectors, intake, rockers, etc.

i do not know these answers, hence why im trying to stay where i was with just some 103 jugs.

 

I have rebuild numerous engines. Just put the engine in the Jeep you see. Had 300k on it. Stock standard cylinders have a roughing crosshatch require stock rings.

Same practice for a two cylinder motor is pretty much the same. Any shop that has the ability to bore the cylinder should have the clamp plates to simulate the clamping of the head to the cylinders.
Other then that, tolerance just need to be maintained to the service manual.
Rings seal by compression coming down on them and expanding them out to the cylinder and against the bottom of the piston groove. A little gas gets by the ring gaps. Also why a small scratch makes little difference on a street motor.
I scratch my head when you say you don't want to drop a $1000 in it yet you demand it to be perfect.

 

i will admit that i wholefully underestimated the price yes.
but i scratch my head when searching for a set of new stock sized jugs morphs into "you need new pistons too".

 

You should be able to find them on flee bay.

https://www.ebay.com/itm/103-Twin-Ca...0120:rk:5:pf:0

https://www.ebay.com/itm/Harley-Davi...ioB:rk:20:pf:0

I've bought take off 88 and 96 tc cylinders for as low as $40 a pair and bore them to size.

 

ok to everyone who has tried to help me, thank you. ive gone back through all my tabs and bookmarks and other resources. i have found where my disconnect is and im willing to admit where ima dumbass, again.
i understand the tolerances and the reason why for pistons. but i underestimated the stress of that point. My bike is not that old, why would the pistons be away from initial measurement. but the problem comes from machining a block apart from the pistons that you are putting it in i.e. im building a 350 so you put the correct size pistons in it v.s. im rebuilding a 350 so i better swap out these pistons cause god knows where theyre all at in size.
that makes sense and for the life of me i wasnt seeing it in this case.

thank you for yalls patience.

 

I've been lurking this thread.
Did you reply to DJL's PM? He is one of the more knowledgeable Engine guys in here.

 

i have most definitely been talking to him. His PM's is one of the things that helped me un**** myself.

 

Hahaha! Alrighty then!

 

compare auto engine pistons with HD pistons. Look at the length of piston skirts...

Not totally sure, but wouldn't a shorter piston skirt create issues other than piston slap when the gap between piston and cylinder is larger?

I seem to remember, some years back, a post that featured an HD piston that had flipped almost 90 degrees (not necessarily because of this issue)