04 RM 125 - Eric Gorr 144

[beaner]

I've hardly ridden the RM the last 2 years, but I'm back on it, and doing well. I think I can use the extra power now, and since I've owned it since new, it's probably not a bad time to tear it down and see how everything looks inside.
My question is about the porting. There are 3 powerbands available.

    More low to mid-range with a flatter top end. By concentrating the power down in the lower revs it makes a powerband that lugs without chugging yet is responsive enough to steer with the rear wheel. Perfect for technical mountain climbing, single-track, Arenacross, ice-supermoto, beginner mx, short-track and TT.

    More mid-range to top end and a bit softer off the bottom end. This choice is best for expert mx, desert, dunes, dirt drags, beach racing, and dtx.

    Wider smoother powerband with less mid hit in the mid-range. This choice makes the power wider like a 4-stroke but without the harsh deceleration. It?s great for intermediate mx, off-road, hill-climb, and intermediate mx.


I was thinking about the last one. I'm a 50 year old vet, and probably run at a mid pack intermediate level. but I still want the hit of the 125 

Does anybody have experience with the different porting he does, and how it actually feels on the bike? Is it really a big difference, or is the feeling pretty subtle, based on the stock RM's powerband?

[streaks383]

I do, not on a 125 though, I have a yz-295 that he ported with the one you are considering.  I love it, it is what he uses on his bikes.  I would stay away from the bottom to mid on a 125 unless you just put put around.  The mid top is great if you are serious about motocross and you can ride like it.  But for me and I imagine most others the mo-betta porting is the way to go, super smooth and don't let the less mid range hit fool you, it will still be stronger than stock was.  I have ridden 295s in all three portings, the bottom mid was great for woods, the mid top was insane and the mo-betta is fantastic!  Eric does great work and well worth the money. 

[fabbo]

What does Mo-Betta mean?

[dbf498]

What does Mo-Betta mean?

According to Eric's website the "Mo-Betta" porting has "a wider smoother powerband with less hit in the mid-range" which I have on mine. He also did the big bore on my 125 and haven't had any issues with it; that was five years ago. To be honest I haven't tried the other two porting options he has because I wanted the ability to ride on the track one weekend and trail ride the next.  Also, this porting is a little more forgiving if you flub up; it'll scare you just not maim you.

I have to agree with Streaks 383; his assessment is spot on.

http://www.eric-gorr.com/serviceorderform.html