Hi folks, quick history - bought a 1997 savage, ~6,800 miles, knowing that the engine didn't have compression when I bought it.  This is my first engine tear down - and while tearing down the engine, I found the following:

- The cam chain tensioner was missing, along with the adjuster assembly completely apart with the adjuster spring in pieces (this may have been the culprit to the damages described below);  I plan to order verslavy mod, and have ordered a new tensioner, and chain;

- The cylinder head seemed to have no noticable damages, neither did the cam;  The cam chain had a "kink" in one particular area, so I will be replacing it;

- The top of the piston seems to have a fair amount of gashes/scratches (see picture), and clymer didn't have any suggestions on the condition of the top side except for not removing any of the carbon deposit; I didn't clean the piston at all, I found it as pictured; The side of the piston cylinder looked fine, one of the rings broke off while I was removing it...

- The valves looked ok with no obvious damage, and was within the clymer specs (so I cleaned and lapped the valves );

- I took the cylinder out and have cleaned it and glazed the inside with a hone;

- The previous owner seems to have done a half-a$$ job of putting the engine together after attempting to "fix" the bike, and found goopy RTV gasket sealer used super liberally especially around the cylinder head, head gasket, and head bolts, where he tried to "glue" the bolts back to the cylinder head with the gasket sealer;  

Based on the attached picture of the piston - I am looking for advice on whether the piston looks re-usable because of the numerous gashes/scratches, or should I bite the bullet and buy a new piston? Anything else I should inspect?

Really appreciate the help!
MJ

Those scratches when magnified look like tool marks from your previous owners poor work.  They could be polished smooth if you don't want to pop for a new piston.  
I have seen worse, the key is no edges/burrs that can heat unevenly at speed...causes hot spots and eventual failure.  Usually on a long dark, lonely, rainy road, with no cell service....might want to reconsider that piston purchase now.      

In that deep, going back stock seems a shame.
How do you like to ride?

From what I can see, that "triangle" looks deep into the surface of the piston's top.   If so, personally I'd replace it. But you should get one of the more experienced builders' opinion.    
Note: Think about where you want to be with this bike down the road i.e. Café racer, bobber, cruiser, touring, and what is your "budget" ?  Right now you are in a perfect position to get the motor where you want it and if you are doing it yourself you can a pretty serious engine on a pretty reasonable budget.  

I'd like an explanation for the triangle. Looks like it's deep and edges look like it's punched in while Hot, as in, manufactured.
If someone wants Me to know what side goes forward, putting the mark way over on one side seems weird.
I can understand forward and rearward on a two cycles, but not sure why on a four stroke, unless the wrist pin is off center. Seems like I remember seeing something about that.
Of course, high compression, close fit, valve clearanced, naturally, gotta be One way only.

Considering it's a flat top piston with no valve reliefs and only 8.5:1 compression, the combustion chamber must be huge! If there were valve reliefs I can see where there would be some sort of designation for front. Being a flat top, I can't find any reason to point the piston a certain direction.

Kris01 wrote on 02/23/16 at 18:49:38:


The wrist pin is not located in the center of the piston....it is offset to help even out the load and wear on the piston skirt and cylinder wall.  When the crank is on the compression or power stroke, the rod is at an angle to the center of the cylinder, and sideways loads are placed on the piston.  The cylinder pressure during the compression stroke is far less than on the power stroke - so the pin is offset to help reduce the sideways loads during the power stroke.

Kris01 wrote on 02/24/16 at 05:04:20:


Every engine....long or short stroke has an offset piston pin.  

The amount of the offset is most likely changed to match both the stroke, and the length of the connecting rod.  Even with very long strokes you can get a mild rod angle.....if the connecting rod is made to be long - the downside is that the engine becomes very tall, and becomes heavier as the height of the cylinder/block must be increased.