2011 RMZ450 vs. Eric Gorr 2006 RM300

I thought this might be useful to post here:

A little bit about me, I’m a 36 year old vet B/C weekend MX racer. The 2 stroke is a 2006 RM250 that I picked up in July of last summer for $2500. It was box stock and had about 10 hours on. It was in excellent condition. I was coming off a 6 year absence from riding and I just wanted to get something cheap in case I decided that I made the right choice 6 years earlier by giving up (previous bike was a 2003 CRF450). I went to my first local race that weekend and I was hooked all over again. After the season I ordered a 2011 RMZ450 but after about a month my dealer told me that they couldn’t get one. Since I had my heart set on the RMZ, I figured I would wait and just do some work to my 250 and ride it one more year. Here are the mods:

-FMF Factory Fatty and shorty silencer

-Eric Gorr 300cc kit with porting and head work - $600

-Factory Connection revalve and respring

Eric does amazing work. The cylinder was rebored and plated and it looked perfect when I got it back. He had to modify the exhaust valve and reed cage for clearance. With the kit comes your choice of porting. The choices are bottom to mid, mid to top or a broader smoother power all the way from top to bottom. You also get your choice of head mods. Since I ran race fuel anyway, I chose to go with the high compression head and the broader more smooth power band.

The RMZ450 is a 2011 that I picked up in December of last year but I didn’t ride it until about six weeks ago. I had already done the work to my 250 because I was not expecting the bike to show up but out of the blue one arrived at my dealer so I grabbed it. Here are the mods:

- Rekluse Core EXP 2.0

-Yoshimura RD4 Full Ti exhaust

-Factory Connection revalve and respring

I’ve got 7.4 hours on the 450 so far and the first thing I can tell you is thing just pulls and pulls and pulls. The pull is probably exaggerated by the traction. The back wheel feels glued to the track. Because of that it has roll on power everywhere. When cornering conventionally while using the clutch (which you can still do with the rekluse) it turns like it’s on rails. Since installing the rekluse I noticed that it pushes the front end a little bit more when you get lazy and just rely on the rekluse. I assume this is because the front end gets abruptly unloaded and light as opposed to gradually fed power with the clutch. I’m also running the stock tires so that might have something to do with it. In spite of this, the rekluse is the best mod you can do. The bike WILL NOT stall. I was having a problem stalling it at first because the clutch would not totally disengage. I was told that in order to have a real smooth and easy clutch pull they lengthened the pivot arm on the clutch. I’m not sure if this is true but if it is then in doing so they made it difficult to ride because the bike will stall if the clutch isn’t all the way to the bars. Rather than deal with it I just installed the rekluse and it is awesome.

The RM300 is everything Eric Gorr said it would be. He told me I would ride a gear higher because the motor can pull it now. He told me that the horsepower would be well into the mid 50’s but it would feel weaker because the violent punch would be gone. He also said that because of the porting it would make peak hp a few hundred rpm above stock and pull smooth all the way there. He was 100% correct on everything he said. On tight bowl turns I would just come in, in 3rd gear, turn the front wheel down the bowl, feed it a tad bit of clutch and the motor would sing for as long as you wanted to hold it open. It doesn’t have the 450 roll on power but it’s probably as close as you will get out of a modern 2 stroke. As far as handling, it was not affected at all by the mods. The thing turns ridiculously and it sticks in the rutted turns better than any bike I’ve ever ridden.


The 450 is an awesome bike and it handles and turns as good as any 4 stroke I have ridden. It has power everywhere and is a blast to ride BUT, the 2 stroke with the big bore has more than enough power to keep up at the level I ride at, it handles better and is about 30 pounds lighter. So far, I would have to say the 2 stroke is more fun. I timed a few laps on each at my local track and I’m faster on the 2 stroke after the mods. More power on a 2 stroke usually means more out of control or harder to ride. That’s not the case with the big bore. It’s is noticeably more power than stock but the power is dispersed so evenly and in places where I can use it more effectively that the bike is actually easier for me to ride. I only have about 7 hours on the 450 so I might get better on it with time and change my mind but for now, the 2 stroke is my favorite of the 2.





Very nice bikes you got there! Nice to hear a good review too, thanks for that.

And realistically ~300 is what should be competing with 450s. AMA is just happy to oblige the Japanese manufacturers with killing off the two stroke so it will never happen. Sure you can get as much horsepower from a 250 as from a 450, heck you can get more, but you need CCs if you want to be able to spread that power out in a usable fashion.

I agree, the 500's get a bad rep because some of the non powervalved bikes made terribly brutal power delivery. When setup right the big bore two strokes are very easy to ride fast, a 300 pinger is a much better comparison to a 450 thumper

I loved my kx500, if I can ever find another one that's not overpriced I'll buy it

I just restored a 99 KX250 as a project bike for a website and had EG do the 295 with pvalve svc and a new crank. Can't get it to come up on the pipe at all. Jetted it fat and lean with no difference. reeds and pipe ok, pvalve seems to be ok, though there is about an 1/8" freeplay in the exhaust flapper valve when the actuator is fully open. not sure if this is normal. Eric is sending me another head gasket to try...anys suggestions? I know its gonna rip when dialed in, Im scrambling to get it ready for this wekends GNCC at Snowshoe.

Wow, thanks bud, you just saved me mucho $$$, I was thinking of getting a 450 and getting rid of the 300.

I am having a blast on the 300 but wanted the pull of the 450. I think I will just stick with my 300 and keep it cheap and fun.

Awesome bikes man....it's nice to hear someone still likes 2t for mx!

they should let 250 smokers race with 450s

your rm250/300 will smash a 450

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now