First off, Thank you for taking the time to read this. I have had my '05' DR-Z400s now for a few years and after a few months of commuting to work, about 30 miles round trip, I started to hear a weird almost humming noise I guess. Then it quicky started to get worse so I shut it down and put it away because I didn't want whatever was going on to get worse or even worse ruin the engine. I thought it was a rod bearing and I turned out to be correct but that was only a piece of it. Basically I need and entire rebuild and I cannot afford to rebuild it cause it is pretty expensive for parts on this bike. So I searched around and tried finding a cheaper route so I can get this thing together again and I found on eBay people sell used oem parts... I thought perfect! And I bid on some stuff and I ended up buying a crankshaft and rod out of the same year bike as mine and it only had 1k miles on it before it was crashed then stored then parted out. I also bought the cylinder and piston and rings and pin and I got bran new circlips. All I need really now is all the bearings gaskets and seals and hopefully it'll be good.. my question is I've never put used parts in before so I guess I'm really questioning myself now and not sure if I'm not making the correct decision I guess and has anyone ever done this before themselves? What if any tolerance checks should be done ? Do I have to hone the cylinder ? it looks really good I can see the cross hatch marks easily but I'm not sure if it should be done again or not? And, is it dumb to run the piston and rings even tho there's barely any time on them? New rings?? could I even put new rings with the nikisil cylinder? And I'm going to try and reuse as many bearings as I can as they are ridiculously priced imo... Any help is appreciated thanks again.