Supermini KX 85 or YZ85

Any major difference between the two? One easier than the other to convert? I'm assuming 12" wheels are the easiest, but lacing 17's to a stock hub is not out of the question.

 

In the same boat! Heard the YZ doesn't have a power valve, while the KX and RM both do. No idea what that is or if it's really that important, but I've heard it's enough of a difference to be considered in your decision.

Looking at my local scene in San Diego, the KX is WAY more prevalent than the YZ.

 

It's funny, around here everyone is on YZ. There is one guy that just built a KX and he likes it. The YZ is harder to ride without the power valve, but does make a little more power. When you get the gearing and shift points sorted out, I think the YZ is faster. KX is easier to ride. Not a major difference between the two. Another racer (with $$) just built a brand new 2017 TC85. So far he is still faster on his YZ. We all run 17s.

 

Here's my YZ85 with GatorRimz 12" wheels with Mitas racing rubber. It certainly needs help right off the bottom, but with the gearing that Gatorrimz has for this bike it's basically ready to go. 415 chain and sprocket setup, FMF pipe, Boyeson Rad valve and she can power wheelie in the low gears. No need to clutch pop or snatch it up.

 

Here's the YZ85...

 

I'm curious about the 2T bikes too, I have a Grom now, wanted to also get an XR/CRF100 but did recently find a nice YZ85 that peeked my interest. Other than wheels, sprocket, tires etc. what do these "need" in order to have fun on them? My kids will be riding it too.

 

Anyone have experience w/ mag 12" wheels? Mototriad offers them and another UK outfit as well.

 

In my experiance, you need to change the powerband. It's really ON/OFF, and comes jetted rich from Yamaha so that exaggerates it. I use an FMF Fatty Pipe with their smallest silencer (pretty loud but not horrible), rejetted the carb, installed a Boyeson Rad Valve (better for midrange) and with the use of T2 race fuel, it seems to help a lot. Also, use a hotter plug to keep things going under the pipe.

With those Gatorrimz wheels, you'll need their 415 sprocket kit. Comes with a 16T and 15T front and a 35t (i think) rear. I use the 15T front and don't get into 4th (yet) at Herrin's place.