125 modded vs 250f

[Aus_Rider_22]

Originally Posted by land-down-under

what if u had a 125 bored to like 167 with all the pipes reeds etc..i saw one on ebay, it said in the description 4 strokes dont stand a chance...i understand that he was exagertting a little tryin 2 sell his bike, but is there any truth to it if it was to 167cc?

I would think a 167 would have it all over a standard 250f.

The question that I would be wondering is, whether the 167 kit would broaden the power as much as 250f?

Obviously the 167 will more outright power, but will it be wide tractable power that can be used?

[land-down-under]

yeh i guess thats the question..with the 125s power band its an off and on factor..with all that power on tap would it track..well to be honest i wouldnt know

[Satch0922]

Originally Posted by mtk

Exactly, look at Bubba. He ran a 250F at Steel City last year. His comments afterwards was something to the effect of, "That thing is so much faster than my 125 its almost like cheating." He clearly indicated that the four-stroke is the faster machine, given equal riders.

One thing Bubba said and I remember it clearly (because it was right on the money), he said "if I had ridden this 250F all year I think I would have gotten lazy".

What he meant by that obviously is that you can go as fast or faster on the thumper with less effort. I think we can all agree on that.

HOWEVER, the 05 YZ125 is a blast to ride ( I am way to big for one) but the fun factor is a 10! If you race and your a better rider than your competition, you will win regardless of the bike. That is why Bubba kicked butt on a 2-smoke.

[mtk]

Originally Posted by TurboV6

Well, just for arguements sake, let's say that it does take a tenth of a second per shift. Really, that isn't going to amount to an appreciable gain. There are way too many other variables on dirt to single shifting out as a sure fire way to slow you down.

Believe what you want to believe, but you're wrong, plain and simple.

ANY time you lose is a bad thing in a race. If you have to shift ten extra times a lap, that's one second per lap you give up to the guy who doesn't. If you can't see how this plays a role in racing, well, I don't know what to tell you.

Also, street, dirt, it makes no difference. Racing is racing.

[TurboV6]

I certainly agree that any time lost is a bad thing, i'm just trying to be realistic about it. If you are running more than the absolute minimum fuel you need to finish the moto, that's more weight than you need. If you aren't changing your jetting for every 10 degree difference in temperature, you're losing power. If you aren't changing your tires every moto, you're losing traction. Are these things going to slow you down? Probably, but if you aren't a machine, you probably wouldn't notice these small differences. I just point out dirt as being a variable because what might have been the hot line the lap before might not be the next time around, pavement doesn't change like that. I don't want to make this an arguement however. If I have to tap dance on the shifter and rape the clutch a little more to keep the speed up, i'm ok with that, i don't have a salary riding on where i finish

[mtk]

You're right, those are all factors. And if you're racing and not paying attention to those factors, you're beating yourself before the race even starts. I'm not the fastest guy in the world, by any stretch, but I've got a decent trophy collection because I stacked the deck in my favor before I rolled a tire on the track.

Condition of the track or what it's made out of is utterly and totally irrelevant. Really. We could be discussing ice racing and this wouldn't change.

The bottom line is that every time you disconnect the engine from the back tire (a necessary component to changing transmission ratios) you're losing time because you're no longer providing forward thrust to the machine. Likewise, any time you touch the clutch lever, at any amount, you are reducing the power to the rear wheel and consequently the forward thrust you get from the engine. Now ideally when you touch the clutch you're reducing the output to the absolute most the tire can translate into acceleration so you really don't lose anything. But touch the shifter and you can't help but lose ground. Think about it. If you're side-by-side with another guy, when you shift he WILL pull a gap on you. It's simply unavoidable. Do that 20 extra times a lap and that wee little gap turns into a 10 yard lead. Do that for 20 laps and now he's 200 yards ahead of you.

Racing is a battle of seconds. One second a lap is a 20 second butt-kicking in a 20 lap moto. The guy with the 20 second lead is already back at his pits before you see the checkered flag.

The four-strokes have a wider spread of power, resulting in fewer shifts. If you're on a 125 and the guy next to you is on a 250 and you need to shift once, while he doesn't, for the short chute before a jump, he's got the drive advantage on you and gets to the jump first. That means he gets to the next corner first and gets the better line.

In addition, the four strokes have one power pulse every 720 crank degrees, compared to one every 360. That means the back tire gets a big hit of power and then 720 degrees of engine rotation to regain traction. The two stroke gets a big power hit and then has half the amount of time to regain traction. This is the same reason that V-twins get better drives off of corners than inline fours (roadracing) and why the factories developed the "big bang" engines (all four cylinders fired within a short amount of crank rotation) in 500cc Grand Prix racing.

[TheShadyMilkman]

we are far from the starting question but we must also consider that the major manufacturers have been pushing four strokes because of epa regulations coming down hard, there have been fuel restrictions put on fuel that two strokes thrive on to make power in the ama sanctioned supercross events and also factories want the best selling bikes on the track winning. four strokes were designed to murder two strokes, and the only way they had a chance to do this is because of a rule created in the 70s when motocross bikes were terds with shocks, that says 250 cc four strokes could compete with 125 cc two stokes it is obvious that 2 stokes are better look at a 250 cc two stoke and look at a 250 cc four stoke and tell me who is better 2 cycle is more responsive 4 cycle is heavy and complicated so when 250f makes 250r performance then i will give them respect.they are just terds in my opinion!!!!!!!!!!!!!!!!!!!!!!!!!!! go stall 4 stoke lovers !!!!!!!!!!!
-no harsh feelings im just mad there are no 2 stoke funny cars.

[gonzo]

Originally Posted by Satch0922

If you race and your a better rider than your competition, you will win regardless of the bike. That is why Bubba kicked butt on a 2-smoke.

That pretty much sums it up right there.

[mtk]

That is true.

However, if you're an equal rider and you're on a 125 and he's on a 250F, be prepared for a butt-kicking.

To me, that's the problem.

I'd prefer to see rules that made the machinery more even, so if you had two equal riders, one on a 125 and one on a 250F, you wouldn't see a butt-kicking, but rather you'd see them go at it for the whole race.

[gonzo]

No one is ever that equal though.

[mtk]

So?

The point is, the rules are NOT equal. You either ride a 250F or you'd better be a lot better than everyone else to ride a 125.