RM 125 vs144

As an RM125 owner…

IF the 144 kit delivers more torque and better-earlier-power…WITHOUT messing up the way the RM loves to scream up on top?

Do the 144

i blew up my 04 rm 125 in 07 and went the 144 route. Eric Gorr sent me a kit and my local mechanic set it up.

Also did a powervalve mod that was pretty popular back then and played with a heavier flywheel, gearing and jetting.

the bike was awesome. still regret selling that bike.

Having owned my 06 yz125 as a 144 for 15 years.
It greatly depends on who does the work and what you ask for the tuner to tune it for.
I had mine done by gorr and I asked for a track setup. Bumping the cc's up will get you more torque over a 125's.

So I had it ported for more mid and top end. High compression head for race gas.
It ripped was about the same as the 125 off the bottom end. But more forgiveness because of the extra torque.
Screamed in the mid and up top this where it stomped on the 125.

I had to richen up the jetting a couple mains bigger. Gearing it correctly was very important too.
The stock 13t on my yz would wheel spin too much in 1st through 3rd. And wind out too quickly the rest of the time. A 14t front fixed this the extra power it pulls it just fine. I ended up with 14/49 on it.

Had similar results with my friends 06 cr125 that we had gorr do his 139/140 bore on. Ported the same way. Ended up dropping 3 off the rear on his. His wanted the 13t front but the 52/53 you typically run on cr125's. Had the same winding out problem with the larger rear that as a 125 it needed.

Had this same gearing thing on my 21 ktm 150sx. Stock was a 48. I put a 46 on it. And at the 125 dream race at washougal a couple weekends ago. I almost got a holeshot. 2nd gear start and when I hit 3rd I could see myself pulling on everybody. Came around in 4th going up horsepower hill.

My friend who started next to me said it was like I hit nitro.

Someone will be along shortly to tell you 144's don't rev out because of the heavier piston. They just never rode a properly setup one or read too much mxa.

I've owned two rm144s, and multiple other brand 125s and 150s.

Years ago, when you could find them, I bought several 2004,5 rm125 cylinders and Eric Gorr bored them to 144 and we tested several porting setups.

The 2004,5 cylinders work really well at 58mm. The one we settled on actually revved higher than a stock husky 125.

This whole 58mm pistons won't rev is an old wives tale, but they do need proper porting and Gorr has a good setup for sure.

I have a RM144, and it freaking rips, its from Gorr, and I have a HGS 144 specific pipe and carbon silencer, vfroce reed cage, and have the jetting dialed and its crazy how hard it pulls with my fat ass on it.

You will not be unhappy I can tell you that.

If you want videos I have some on instagram of me riding it and you can the bitch rip lol - motomike894

Was lucky enough to get Kyle's hand me down Varner 144 he raced as an intermediate in '03, back when Varner was probably the top 2 stroke amateur guy. Have no idea what kind of parts went in to the thing, Terry took it and rebuilt it himself when it needed it. I don't think I ever really rode a stock 125 when I moved up, but the 144 was a dream.

Bike was a damn rocket and didn't sacrifice any feeling the RM has. Wish I had some pictures of me on that thing, was by far the most fun and favorite bike I ever got to race.

I love these kind of threads. Beautiful RM motomike.

WE THINKED OF GETTING THIS BIKE FOR ME NEXT BUT DIND NO I WE CAN GET IT LOW ENOUGF TO THE GROUND WE WOUD NEED TO SLIDE THE FORKS ALL THE WAY UP TO THE BARS AND MY DAD GET SACRED IT MITE GET HEAD SHAKE ON THE FAST AND LONG STRAITS I DIND EVEN NO SUSZUKI MAKED A 144

I had my 2011 rmz bored out to a 144. Thing flew and was competitive with the ktm 150’s. God i miss that bike, so much fun 💨

Oh...now you've done it...

Tyler's back!

At least Brody hasn't showed up.

Sick.

PS- Your instagram is amazing

I had Rick Peterson at Max RPMs do a 2004 RM 139 motor for me and it rips big time.