I ordered the DR-Z250 300 kit for my new-to-me Drizzlet from Thumper Racing (they said they had a core, and would just send me the kit ready-to-go; I'd get a core refund once I sent my cylinder in). I did notice some oddities about it - the machining cost was twice what they said on the site, and the kit said 340, and oh, the cylinder looked like it was not off of a DR-Z250. A little investigation, and yes, they sent me a kit for a DR250. I'm working out the exchange/partial refund right now, but the one thing that was clear was that they don't have a core over there. So I pulled the cylinder off of my Drizzlet last night; we're going to MotoGP on the big bikes over the 4th holiday, so that should give plenty of time for turnaround before I'll be riding that bike again. A few things that came up while taking the cylinder off... One is that the jetting had always felt off - it felt quite lean, and struggled under load. I decided to just get the big bore, instead of working out the jetting with the stock bore and then doing it all over again. Well, the plug was pretty white, and the exhaust valves showed signs of leanness - and the head bolts were frighteningly stuck. I had to use the impact followed by a breaker bar with a cheater atop (and a coordination of arm strength with my hubby), and we were sure the bolt head was going to break off just before the bolt broke loose on two of them. But they all came out, and all went in the trash. The smell that came up when they came out was strange, like very burnt oil; I think the thing has been running too hot, and that somehow stuck the bolts more than they should have. I did note that, while the weld slag in the header was not present, and the airbox has been cut, and the Yosh is quite free-flowing, the butter-soft screws on the float bowl look unmolested. If all of those mods were done without a rejet, no wonder it was too lean! Any damage from lean-ness should be nicely fixed by a new piston and new machine job on the cylinder, though, so that's fortuitous. And I've put in a Thumpertalk store order including new float bowl screws and new head bolts/washers. I did ride in a parade this weekend, which gave me a chance to try out the Vapor I installed and the EBC SM rotor. I still need to install the tach sensor (again, on my list of Might As Well Do While I'm Doing The Big Bore), but the speedo is pretty necessary for me on the street. I'm trying to decide between an SM wheelset and just putting dualsport tires on the stock rims. Street just tears up the knobbies.