Most obvious answer is .... it's a custom build. A repaint wouldn't explain the serial number.
I have never seen a Fat Chance MTB size listed in cm.Since most serial numbers have some logic to them I would assume the 51 = the size in centimeters which would be an easy check for you. Nice frame regardless and if it's your size build it, ride it and enjoy it.
I think you're right about the chain stays and seat stays on Wicked Lites, I believe they have a smaller diameter. Wicked Lites were designed to be more forgiving and with a slightly a longer wheelbase than the YO's. The one I had rode like it was on a rail, and soaked up the chatter with the factory fork.Thank you for the numbers. Wicked seatstays are slim, smaller diameter than chainstays. I read somewhere Yos have the same diameter tubing for seat and chainstays which give a stiffer rear triangle w/ better rim braking. Your bike seems like a Wicked w/ fat, stiff tubing and that´s awesome.
I don't have a YO, and haven't ridden one extensively; I have a Monster and HAD another Wicked Lite (picture in Avatar) that's now in my brother's possession, and this one definitely rides different than my other Wicked Lite. This one feels more planted, stiffer and "snappier" as you say. Honestly, it reminds me more of my Ibis Mojo, which might be a tad more forgiving. All fantastic bikes.I agree your bike seems to be a hybrid of a Yo and a Wicked, which is awesome. Have you ever ridden or owned a Yo? How does the ride compare if yes? Bought my Yo in 91 and still love it, snappy stiff and fast, but somedays I would like a Yo that is 5 to 10 % less of an all in Yo. To top it off you detail it with a Chris Ingleheart fork on it. That is really cool, nicely done.
A roller stem would be great, but this is a threadless stem. I'm trying a Monkey Lite riser bar on it now which helps the fit; I removed about 10mm of steerer. Don't want to lower it anymore for the moment. Thanks for your comments.Only suggestions I have are to source a decent roller stem, figure out your steerer tube length and cut appropriately. Nothing wrong with the Salsa stem just my opinion. An interesting bike ... Happy riding.