Hi all,I am really glad I bought this LS2, it is very cool.Its complete and virtually everything minus airbox and battery box and cable guide for front fender cleaned up nicely with evaporust.  The crank and pistons and oil pump were a mess.  Basically every part has been cleaned and rust free.  Tank was stinky with rotten gas but that's all cleaned up, petcock redone and paint rubbed out ok to nice, but tons of chips that I will touch up.  The pistons were 0.25 over and I can get a .002" feeler in easily so I am going to rebore so this little thing doesn't quickly wear out itself out.So I couldn't find 2nd oversize pistons and rings (rings specific to this model two different thicknesses), so I bought a 1967 Yamaha YL1 piston kit after determining that the pin, bore were same and hoped that ring gap would not be in a port.  But the YL1 gaps were.  But when I turn the pistons around backwards (arrow towards intake) the ring gaps between ports.  In this position one side of the YL1 piston had a skirt window that was narrower than the LS2, so I laid it out and made them match pretty good with saws and files.  So the only material difference is that the YL1 (or the other way around) piston has a 0.030" pin offset, in what direction I didn't note because I decided it didn't matter since I decided to do this. To the experts - do you think the difference in offset will matter if I don't cruse and 9000 rpm?Also, the math says the timing will change a tad, but probably not measurable unless it was calculated to 3 decimal places?will it run okay?thank youEverything is apart, once I finish painting and get the crank back I will post some pictures, which I couldn't do when I was stripping it down. 

Wow, you're getting ito uncharted territory & best of luck with 'that'.
We watch & wait.
I think they offset the pin to do with wear in the bore, or is to do with causing piston rattle.
Does the cutout on the sides sit much the same where fuel is fired up the transfers.
Is the skirt 'now at the exhaust side' wide enough to cover the exhaust port at tdc. I'm impressed but i'll now loose sleep over it lol.
Keep the updates coming please.

Hard to see in photos but really close to identical minus offset.  I used pin in soft vise to align and scribe using sharpee as bluing ti scribe. Small very fine saw and points file and tiny round file to clean up 
Pics

Great pics thanks. Love your ideas. Do you have a pair of second over kits or making them up from separate items bought. Looks like a 'new first over piston in one pic or is that just for reference to compare, plus a second over in one pic.
Don't worry, i'm tired & not thinking right-- & it's 3 in the morning lol.

I wonder if Enduronut or DEET might have pistons?

i have 1st and 2nd oversize...
I plan to sell the 1st OS, which is for LS2, on soon
The 2nd OS are the YL1 pistons I modified
I am going to go forward, see what happens because if it does wear out .in my lifetime I can go to a 3rd OS.  If it comes unglued for some reason, which I do not foresee, then oh well then I know I shouldn't cruz ebay while drinking cocktails

been there done that 

HT1kid - did this same type of mod work for you?
I have jugs in machine shop for a nice tight no slap fit so I am optimistic 

Msavitt I was talking about drinking to much beer while on EBay  

Msavitt . . . I've been both following this thread, and trying to ignore it at the same time . . . Let me explain 

I've been avoiding comment, because I don't want to rob you of, what on the surface, looks like a very cleaver idea !
I think it's great that you're thinking outside the box to solve a problem . . . I do it all the time.

However, my conscience is telling me to speak up, at the risk of dashing your enthusiasm.
I've much experience in the area of piston modifications (including welding mods), so thought I should share some of what I know, in order to give you a broader perspective on this experiment.

What RT325 said in post #2 is spot on:
That the factory's wrist pin offset helps reduce piston slap during transition @ tdc.  Reversing the offset may increase noise, rather then reduce it.
Also, what you said is true about it effecting the timing, . . . but of no consequence if timing is adjusted to compensate

But wait, there's more . . .
If you examine the photo's in link below, please take note that the engineers designed additional material to reinforce the intake skirt which is subjected to much higher loading then the exhaust side ever sees.  Turning the piston around , now puts that tremendous pressure on the weaker piston exhaust skirt.

Further more . . . from a mechanical engineering stand point, all that force is now going to be concentrated at the sharp 90 degree corner of your modified transfer port opening.  "Most" engineers (and some machinist) know that creating a radius in a turn will greatly reduce the point of stress by spreading those forces out over a much wider area.

Lastly, ring gaps were put on the intake side for a reason . . . .to get cooled by the incoming mixture.  Placing the gap on the exhaust side will be more susceptible to creating a hot spot at the ring ends . . . a hot spot that could encourage detonation.

Hope you consider what I'm saying, and that it helps you to make a more informed decision as to trying this.

Picture of your piston mod, (also note the factory reinforcement to intake skirt), and then an extreme example of a stress reducing radius that spreads the piston skirt's forces out over a much wider area.
When your piston breaks, (and sorry to say . .  it probably will),  the damaged incurred will probably cost you much more then a re-bore to 3rd oversize.

There, I said it . . . now I can sleep better tonight!

Pictures: . . .  double click on photos to enlarge them
drive.google.com/drive/folders/1SiY7hgUV...kDip4?usp=drive_link