CR250: When does the low-end hurt you?

[halowords]

Just wondering, when does it hurt performance the worst on the current 250's?

Also wondering, how close does an EG Mo' Better port job get it to the YZ or RM 250 engines in terms of low-end power and being competative? I'm not planning on racing and I'm relatively new to motorcycles in general so I'm not sure it really affects me too much one way or the other, but I'm trying to decide between an '02-'03 CR250 and a Mo' Better port job, or an '02 CR250 chassis with a YZ250 or RM250 engine transplant for a fun project with my Ol' Man this winter/spring.

-Cheers

 

[john3_16]

I'd forget about trying to translpant the motor...A port job will give more power than most can handle for more than a couple of laps...Really, any 02' or 03' model 250cc 2 stroke that's ported will be putting out almost too much HP and there won't be much difference between all the bikes...Some may be a little stronger here while being weaker there but all will be stronger than stock...

Knowing this I'd go with the best suspended and best handling bike because you just can't bolt on good handling...And again, there is no real bad handling bike in those modle years but the CR has this category hands down...Stable, corners good, almost too easy to jump, and almost as light as a 125.

 

[mtk]

Dave,

You're going to worry yourself bald over this.

Buy a bike. Ride the snot out of it. Worry about the rest of it next winter. A bone-stock 2002 CR250 will pucker your sphincter just fine, top, bottom, or in between.

All I've done to mine is replace the stock aluminum clutch plates with steel plates and that added enough flywheel effect to make the bike stall less when trail riding. Anything beyond that is gravy. I'm going to "Mo Betta" my 2002 this winter for a couple reasons, none of which is that it really, really needs it. The only reasons I'm going the "Mo Betta" route is that for little more than the cost of having the RC Valve cleaned and serviced, I can get the valve serviced and get the engine ported by a respected expert.

Trying to stuff a YZ or RM engine into a CR chassis is a lot of hassle for very little gain. You'd have to be an expert motocrosser to tell the difference, and since you're not racing, why bother?

 

[halowords]

Dave,

You're going to worry yourself bald over this.

Let's hope not. :) I'm actually just doing research because 1) it's fun and 2) I've got some time to kill before I actually buy a bike. I was considering the engine transplant because my dad likes to tinker with stuff (he was a welder and airplane mechanic in the Army and a Combat Engineer in Vietnam) and thought it'd be an easier project than the '69 Plymouth GTX rebuild he wants to try in the next couple of years; easier particularly in trying to convince my mom and wife amongst other things as my dad and I have to get their approval before buying the said muscle car and storing it at either of our garages.

So don't take it personal. Just asking a crapload of questions for the fun of it! ;) I think talking to all of the Fizzer-400 people made me more paranoid about the handling than HP's anyway, so it's inevitable that I get a Honda for that reason alone. Either way, it's going to be stress-free as I'll be happy to be on a bike regardless of what it is, especially the first few seasons.

-Cheers

 

[Sandy Whoops]

1. When trail riding, the inability to gently loft the front wheel over an obstacle such as a fallen tree.
2. Wheel spin in sand.
3. Exiting a corner, 2nd results in wheel spin and 3rd results in....not much.

With the stock motor, the power band is too high and narrow. Not that there isn't enough power, it's just not very usable in many situations. After Mo' Better, the CR is easily twice as much fun to ride.
I don't think I have as much bottom end as a late model Zook, but I like the overall CR package much better.

 

[mtk]

Ok, but if you're going to build something, make it something worthwhile.

Stuffing a YZ250 engine into a CR250 frame is really only a benefit to someone who motocrosses full-time and is good at it to boot. That combination has no real benefits to the occasional trail rider. At least as I see it. The shortcomings of the Honda can be dealt with a lot easier via porting and tuning for the type of riding we do.

So, go buy yourself a 2002 CR250 and have Eric Gorr work his magic on it. Problem #1, selection of a dirt bike, has been solved. Add in a Keihin PWK carb and a flywheel weight and you're good to go on the dirt bike front.

But we've yet to solve the "Dad Project" issue and a Plymouth GTX takes up a LOT of garage space. I'd offer this solution: Pick up another 2002 CR250 and a 1991 & up CR500. Sell the 250 engine on **** and everything non-engine from the 500 on there as well. Give the whole mess to Dad and tell him, "put this engine in that frame." If Dad can weld aluminum, you're in, other than getting the new frame bits machined (unless he can do that too). The end result is a product WAY more fun than the GTX.

I wouldn't worry about the handling, power, or anything else. Any late-model dirt bike is a fine machine and will be plenty of fun, have plenty of power, and handle well enough for whatever you'll be doing with it. I know I'm the limiting factor on all my bikes handling prowess, including the 1982 Maico 490.