How does the 2 stroke 250 stack up against todays 4 stroke 250's

**Scaramouche** · 09-01-2009, 02:12 PM

.The thread started by Desmo begs a question, I have to ask...It has been some years since I rode a 250 2 stroke. How do they compare with todays reign of 4 STROKE BIKES and which would you prefer..........TC

**XXX3** · 09-01-2009, 02:17 PM

2 stroke 250cc bikes utterly and conclusively rape the 4 stroke 250cc bikes. Your very pinnacle of 4 stroke 250cc bikes, the CBR250RR has about 40hp and is based on a 1990s chassis design. It's good for about 180kmph or so I've been told.

By contrast a two stroke Aprilia RS250 has about 70hp claimed, is significantly lighter than the CBR250RR, has a modern era chassis with fully adjustable suspension, and is good for at least 210kmph.

**rgvlee** · 09-01-2009, 02:18 PM

there is no comparison.

2T is the only 250 to own if you want to go fast.

**Satan1** · 09-01-2009, 02:23 PM

It's been done to death in the thread but:

I rode a tzr, nsr and rgv when looking at a 250, decided on the tzr due to the power delivery.

Then after it was ruined (stolen/recovered) I went through a 4 stroke fzr and cbr big difference in power? noticeable due to the delivery but not really a massive difference. (By this I mean if you can handle one you could handle the other in terms of max output, delivery different kettle of fish*)

Weight? The four strokes felt way heavier.

Handling? no comparison the two stroke leave the fours for dead.

Braking? The 2 strokes win again.

But since the early 1990's the 250 has only been produced to satisfy archaic laws in some countries, there is no longer a need in japan.

Riders needed in japan to go 250, 400, open class this breed nicer 250's and 400's as each manufacturer wanted a piece of the pie.

The latest 250's are average, Fit for purpose but not pushing any boundaries.

You can learn just as much imo on the four stroke, it's just not as fun.

Edit: *I can see this causing drama yes the 2 stroke put out more power but it isn't mind blowing. (although I grew up riding dirt 2 strokes...)

**thro** · 09-01-2009, 02:58 PM

Top end power: typical 4 stroke twin has about 33hp\
Typical 2 stroke 250 (eg, RG250, NSR50, TZR250, any of the JDM bikes) has 45hp, unless its an RGV or RS, in which case you're supposedly up near 60.

The big differences are in weight, equipment spec (adjustable USD forks and twin discs vs non adjustable suspension and a single disc - unless you're talking one of the early-mid 90s 4 cylinders like the babyblade or ZX2-R - but they're quite a bit heavier) and top end power.

Through the mid-range a typical 4 stroke 250 will cane the stroker.

My rgv for example has *nothing* really until 7000rpm.

Off the line, i'll either comprehensively own a 4 stroke, or bog it and get comprehensively owned myself

Point to point, if you can ride the 2 stroke will be quicker. If you're a noob and cant keep in the powerband, i reckon you may well end up quicker on a 4 stroke due to the more friendly mid-range. it would at least be close, anyway.

edit:

Aprilia may CLAIM 70hp out of the RS250. I'm sure they CLAIM many things. Its an RGV motor, and they don't make 70hp

**kiknet** · 09-01-2009, 05:23 PM

While it's a little unfair to compare but if you look at the GP machines mainly being the RS and the TZ 125/250 from what I've read a good rider will leave others for dead on the track with one. Although while it may make 85hp-90hp/110kg, rebuilding after every race and rebuilding cranks like every 10,000ks doesn't sound too attractive.

**speed3** · 09-01-2009, 05:31 PM

2T will always win hands down with riders of similar capability due to the chassis and brakes. De-restricted strokers buy a greater margin.

**footer** · 09-01-2009, 05:31 PM

The KR1-s still holds the land speed record for the fastest production 250 = 136mph.

The 2strokes are a differnet animal. If you know how to ride one then you will shit all over a 4 stroke. If you don't then you will be the slowest bike.

**thro** · 09-01-2009, 07:47 PM

^^ yup

you need to *ride* the two stroke a lot more - if you're caught off-guard or out of the powerband with a roll-on against a 4 stroke, he'll be getting a few bike lengths on you before you get it out of the hole...

but, thats part of the appeal

**mark_r** · 09-01-2009, 08:11 PM

Originally Posted by thro

My rgv for example has *nothing* really until 7000rpm.

Neither has my 4cyl 4stroke Across. :S

**ritza** · 10-01-2009, 07:09 AM

what about the smell !!! nobody has mentioned the smell !!!

**chrisr** · 10-01-2009, 07:35 AM

yep the smell, sound and powerband, you just can't beat em!

**TYSON** · 10-01-2009, 07:41 AM

Originally Posted by footer

The KR1-s still holds the land speed record for the fastest production 250 = 136mph.

Yeah but who keeps their shit stock.

Yamaha hold the modified 250 record @ 157mph

**Satan1** · 10-01-2009, 10:36 AM

Also isn't because the Kr1-s is a 'super bike' But simply because they had to make the top gear longer than they had planned due to noise testing regulations at the time. ( can't remeber exactly but was measure at the rpm of 100kph in top gear or some such.)

**thro** · 10-01-2009, 10:54 AM

Originally Posted by mark_rattigan

Neither has my 4cyl 4stroke Across. :S

Yeah but what does that rev out to?

The RGV hits the limiter at about 12....

RGV power delivery:

0-7000 = nothing. not "oh this is a bit slow" but really... it won't accelerate any quicker than a 50cc scooter.
7,000-8,000 = picking up a bit
8,000-10,000 = power valve opens stage 1 = ooh i actually have some power now

10,000 - 11,500 = second power valve stage opens = aww yeah
12,000 = limiter

If you really want to ride the bike hard, you need to keep it between say 9,000 and 12,000 rpm... 1/4 of your rev range to play with.

Or, on your across, something like trying to keep it between 12,000 and 16,000?

edit:
Not complaining at all, its a blast to ride. But unless you're comitted/skilled enough to do so and abuse the clutch to get revs up when you slip out of the power band... you may well be quicker on a 4 stroke. That extra power you have up top comes at a huge detriment to the bottom end compared to a 4 stroke - even one of the 4 cylinder screamers...

**lit** · 10-01-2009, 05:48 PM

The pre 90's CBR's did not have power restrictions or speed limiters at 180kph and the reported top speed was just under 210.

Posted via Mobile Device

**Rob** · 10-01-2009, 06:09 PM

eben 2 stroke dirt bikes make 2 fiddy 4 joke look stupid

[ame=http://au.youtube.com/watch?v=LcIzu8VL4ng&feature=channel_page]YouTube - CR500 Vs CBR250[/ame]

**druu** · 10-01-2009, 06:34 PM

Originally Posted by Lit

The pre 90's CBR's did not have power restrictions or speed limiters at 180kph and the reported top speed was just under 210.

Posted via Mobile Device

..and took 10 years to get there.

**Sumatie** · 10-01-2009, 06:46 PM

Originally Posted by Yuggert

2 stroke 250cc bikes utterly and conclusively rape the 4 stroke 250cc bikes. Your very pinnacle of 4 stroke 250cc bikes, the CBR250RR has about 40hp and is based on a 1990s chassis design. It's good for about 180kmph or so I've been told.

By contrast a two stroke Aprilia RS250 has about 70hp claimed, is significantly lighter than the CBR250RR, has a modern era chassis with fully adjustable suspension, and is good for at least 210kmph.

Used to get a top of 205kmh out of my baby balde but yeh an RGV250 or similar would have eaten it.

**TYSON** · 10-01-2009, 06:50 PM

I want to turbo a cbr250rr, lets see how the powerband would be on that..

The power delivery of the busa reminds me of my old rgv.. just quicker

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