Son is thinking of selling his 250F and getting a 144 kitted 125.

From what I have heard the 144 still does not have the power of a 250F. At least not with the broad spread. I recently read a CR144 build and they said the power was in a very narrow band. But the CR125 is no fire breather so maybe another 125 would be better. I have thought about it with my KX125. Maybe a 125 with a pipe and VForce reed block would be a first step.

Vibration? Most 2 srokes I have ridden vibrate much more than a 250F.

Rebuild? The newer bikes are become more reliable and I don't think it is a foregone conclusion that you have to replace everything all that often. Piston life is much better than a 125 for sure. If you keep the vavles in spec they will last quite a while.

I don't think you should expect to turn a 144 is to a 250F killer. I may be fun to ride but I still think the performance edge goes to the 250F

I disagree first off that article your referring to is from dirt rider from a couple months ago they bored n stroked the bike and it was done by max power. I read that article and it would of been better served up as toilet paper. I'll post tonight when not at work how I like my '06 YZ 144 EG modded for me pulling guys on 250F's n up with it has been a blast especially up horsepower hill at washougal, I can typcially pull like a bike length n half on my friend with an '06 CR 125 easy! Even it we start dead even on the pipe. He's jealous as all hell right now.

It is difficult to compare the 144 to my old stock 125 (or any other 125 I've ridden - I haven't been on one of those monster 2006 KTM's or YZ's). There is no comparison. The stock 125 had maybe 30-32 HP peak. A stock 250f is maybe 30-33 HP peak. The 144s vary from 36-39.5HP peak depending on the tuning. My guess would be that I gained 20% HP pretty much everywhere.

Eric Gorr has a very good reputation for the 144s, but he's not doing work until fall. He did my whole kit, including piston, ring and reassembly for $450. I think it was $475 before he went to England to work for the summer. I had "mo betta everywhere" porting and high compression (14.5:1) for race fuel.

I will post links to my initial impression and other stuff below.

You can also take a look at the "Do 144s compete with 250f's thread" - but beware - it gets kind of messy in there. ;)

I recently was able to ride several laps on my 144, a 2006 KX250f and a 2006 YZ450f back to back to back on my practice track. Hard pack with soft sandy berms.

The 144 made me feel like I was going faster. ;) I think that is a result of the sound of the 2 stroke and the fact that you're working harder. If I got off in the soft stuff in the corners, the sand caused much more wheelspin than the 250f and robbed my power. The 144 handled better and I felt more comfortable - but then again, it is my bike. I would say that I had more fun exiting corners (when I hit them right) on the 144 because of the hard hit.

The 250f was easier to ride fast - less shifting, and it didn't matter as much which line you took in the corners. I guess the best way to describe the 250f was "less concentration required." It was easier for me to get up speed to clear jumps very close to the corner exit - but I was able to clear anything on the track on either bike. The 250f felt tall and a bit top heavy, but we knew that already. . .

I think that for the first 5-10 laps, my times would be very close. I am quite sure that I would get progressively faster on the 250f as I got tired. However, the races I run are typically only 5 laps, so that's not really an issue. If they were 15 laps, it would be a different story.

As to a 250 2 stroke - I don't think you're going to make a small bore feel like that, but since a stock 250 has maybe 43-46 HP, the possible 38 or 39 HP of a modded 144 is getting pretty close as far as peak - especially given the weight difference.

First Ride Report:
http://www.dirtrider.net/forums3/showthread.php?t=126800

Reliability:
http://www.dirtrider.net/forums3/showthread.php?t=124121

Race Report:
http://www.dirtrider.net/forums3/showthread.php?t=133418

MXP1MP said:

read that article and it would of been better served up as toilet paper.

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Yep. The Dirt Rider guys don't seem to understand anything since they had it stroked. As I understand the new 144 rule, it only allows boring - not stroking. Thus, their 144 is not even legal in the 125 class - and they stated that it was.

The description they gave of their 144 was NOTHING like mine. Their's had numerous "bogs" in the powerband. Mine has none.

BTW, my 144 revs better than the stocker.

I would say just get him a cheap 250 by the sounds.I am 15 now and last summer I had a 1979 kx250 and never got hurt once and now I have a 1995 cr250r and i only got hurt once because I was riding it with a flat bald tire and rim with bent spokes which does no good and I hit a jump in first endoed and went over the bars.unless he is like 11 or younger I say a lower 250 2 stroke is the way to go.

How about a 250 2T with a flywheel weight added?

Have you thought about a KTM 200 ? I've never ridden one, but from what I've seen at the practise tracks they seem pretty good, though I've never seen one race as they don't seem to fit into any of our classes.

Piston life is much better than a 125 for sure.

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Are you sure about that ?

No the 144 doesn't have quite the same torque it's more like a 200 but don't forget things like porting make a difference and I had mine ported for mid/top I don't deny that it is not a 125. But part of what makes it so much fun to ride is how high it rev's up.

If he's a big as you say he is then maybe you should really consider the 250, I think he's shown you he can ride one. Besides what happens if you go the 144 doesn't like after a year etc money wise the 250 will be cheaper, hell just get another RM and you'll have common parts you can just swap.