An aluminum frame YZ bug recently led to the purchase of two YZ125's.One hasn't lost any clutch cover paint yet and isn't ready to be screwed with.That little turd has a lot more under the hood than I expected out of a bone stock 125.It rips!The other is a nice bike,but it's ready to be torn down and screwed with.I bought it as a real nice running core with the intention of adding a few cc's and giving it a facelift.The certificate of origin's both state an impressive 37.8 HP.Since I'm planning a full "why the hell not" rebuild on my core bike,should I go ahead and do a 144 Eric Gorr kit?Or.....Should I just do a stock rebuild since I can be quite happy with the stock 37.8 HP?Whatever I do to one I will have to do to both.I want them to be set up to run and ride the same.I'm looking for a fun and reliable bike.I don't give a rat's rear end if a 450 4 stroke can out run my little 125.I just want it to be fun and reliable.

144 kit:Do it?Don't?.Fun factor?.........Or just leave them alone and buy a YZ250 to gain some bore,stroke,HP and torque while giving me better odds of one of three having a clean air filter and fresh tranny fluid at all times?

The stroker kits don't impress me.That seems as pointless as building a wimpy little 347 out of a 302 when you can just start with a 351W.I'll add a 450 killing YZ250 smoker before I bore and stroke anything.

Good looking bikes. I installed a big bore kit on MXTerri's son Justin's YZ125. It was an easy to do deal, even though I had to relieve the cases so the rod would clear. You could tell it had more displacement, but it wasn't enough to make a big difference when hauling my 160 pound butt around. Justin loved it, but he was 5'5" and around 130. If I was spending time and money on it I would go with the 250.

I got some YZ465 pistons you can try.

My favorite two bikes of all time are my late model YZ125 and YZ250. Both of which I bought used with low hours, for a small fraction of the price of a new bike. I've ridden a few 144s (none were Yamahas, though), and they are great fun. It all depends on what type of power you ask for. I have a few friends that have had them done by Eric Gorr, and every one of them has been more than satisfied. Ardfarkl on here had a YZ144... maybe he will chime in.

I have given a lot of thought to turning mine into a 144, but I just really enjoy my 125 the way it is. Hands down, its the most fun bike on the market. I probably will send it off to Eric Gorr eventually, though.

The Athena 144 kits aren't very impressive, due to the porting specs (which are almost identical to the stock 125 cylinder, from what I've read). Adds some low end, but is kind of flat on top. With some port work, they rip and are a viable option since you'd then have an extra cylinder lying around.

Thanks guys.Hard hard call.........The little turd was super mean for a bone stock 125 before I tore it down.I'm torn between going back stock or big bore.I hope Mike will go into detail on the before and after fun factor.

Does anyone have a spare five gallon steel bucket I can use as a new jug for the YZ465 piston?I wonder if that 465 piston would make it shake the grips.......?I'll need a cheater pipe for my little kick starter too.

Eric Gorr did my 144. It was incredible. Pissed off some 450s with that thing! Beebout loved it too. That thing rocked!

What I would do is get Eric to do a 144, but use one of his cylinders. It is no ttha tmuch extra and you can put it back if you prefer it the other way. Plus it is a good selling point should you decide to do that!

I WANNA RIDE ONNNNNNNE!

Mike,It will be a good while before I'm finished with them.I'm thinking when the temps cool down a little I might give it a try and see what happens.I'm in no shape to ride at this point,so I'll be taking my time........I bought two,so I just happen to have a spare.That will piss Mark Cody off real bad when his wimpy little 450 gets spanked by a pair of screamin' 125's!

You gotta do the 144. I bought a 136 E.G. complete topend for my '83 yz125 at the beginning of this year and it screams. The bigger bore and porting made a big difference. It came with the new rebuild kit & gaskets, used intake manifold, reed cage with boyessan reeds, and all bolts for $375 shipped. I wanted to build an aluminum frame yz144 recently but the blownup bike that I found on CL sold pretty quick. The 144 is worth the money if you prefer to ride a 2stroke.

Thanks for the input.I'm torn between OEM Yamaha parts and an Eric Gorr top end.I'm tempted to leave the nicer one stock and mod the other bike.I like the idea of being able to drive to Kasson's and pick up a stock Yamaha top end kit.A stock Yamaha cast piston has it's advantages over a Wiseco if replaced often.Years ago I was told that the only replacement for cubic inches is more cubic inches.I assume the same theory applies to cubic centimeters.With that said,I'm torn between stock,134cc's and 144cc's.I have also put some thought into a 153cc kit on one since I plan on replacing the crank anyway...........

look up derrik harris at harris performance. He's down in new braunsfels. here's his company's facebook page. sorry i just noticed this thread is a few months old...

http://www.facebook.com/kirbieajohnson#!/pages/HP-Bikes-INC/110971328962833?sk=wall