The demise of 250cc (and the brilliance of the RGV250)

Doran

Doran

Doran

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Seems sad to me. Not only the GP but the inevitable consequence of no road bikes.

Also, in doing a bit of reading on this, how on earth does the RGV250 do 0-60 in like 3.7 seconds? Why is the New ninja SO much slower than this?
 
Doran said:
Seems sad to me. Not only the GP but the inevitable consequence of no road bikes.

Also, in doing a bit of reading on this, how on earth does the RGV250 do 0-60 in like 3.7 seconds? Why is the New ninja SO much slower than this?
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The ninja 250r is a 4 stroke that makes about 33bhp, it's not really a performance bike, more of a bike for a new rider. The RGV250 makes about 50-55bhp in standard trim, simple really :p

Bit like asking why an Aprilia RS125 is so much faster than a CG125 just because they are the same CC.
 
I suppose what I am really asking is why has no one made a performance 250 anymore?

And why can't a two stroke generate that sort of BHP?
 
Doran said:
I suppose what I am really asking is why has no one made a performance 250 anymore?

And why can't a two stroke generate that sort of BHP?
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Because they need to rev to stupidly high levels to do it and would be virtually unrideable on the road.
 
Doran said:
I suppose what I am really asking is why has no one made a performance 250 anymore?
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Because 250's used to be learner bikes then when they made it to 125's the 400's took over as the next step up as most 125's could out perform a 250 4 stroke.
 
Doran said:
I suppose what I am really asking is why has no one made a performance 250 anymore?

And why can't a two stroke generate that sort of BHP?
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2 strokes can generate loads more bhp than an equivalent sized 4 stroke

motogp used to be based on 500cc 2 stokes up untill a few years ago

Doohan_M_Honda.jpg


However, by their nature 2 stroke engines require to burn 2 stroke oil in the combustion stage hence new powerfull 2 strokes they have effectivley been outlawed by todays emmission requirements (apart from 50cc mopeds:p)
 
if I remember in the junior superstock or whatever it was called you used to be able to enter a 250cc 2 stroke or a 400cc 4 stroke...reason is both bikes make about the same power (55-60 stock).

RGV250 was a god like little bike when it was released, I had the orig KR1 which was also pretty good.. they were both ultra light weight and quite quick, and certainly many times better handling than anything else at the time. The new kwak sports 250 is 4 stroke and just a learner machine, which is woefully underpowered compared with most other bikes.

Like someone else said emissions killed them along with the demise of the 250cc learner bike thing I guess...

I wish they had contiuned the development of RG500 Gamma, RD500 and NS400 ...had piccys on my bedroom wall as a kid, dream bikes. Imagine what they would be like now if improved over all these years.

A 165kg modern superbike with a 1 litre v-four 2t engine, I rekon you'd be able to squeeze 250bhp out of it no probs, probably a lot more. The rush as it come on song and hits powerband would be mind blowing.
 
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Flukestar - an update from my head, btw.

THinking the bike to get us tge CBF600s come summer time. Every review I read about it is that it is technically perfect, a brilliant bike, but boring as hell.

Sounds like an excellent first bike to me; and loads cheaper to insure than a Hornet.
 
Two strokes are, literally, more bang for your buck. Combustion on each crank revolution means power, and three moving parts means very little internal friction. With the same development resources given to four strokes, there's no reason why two strokes couldn't meet all the current emissions regs, in fact several tuners, one of them notable Lotus, have developed multi-cylinder two stroke engines that meet regs, produce significantly more power and torque across the rev range than a four stroke of equivalent size, and are approaching four strokes in terms of fuel efficiency. Problem is, they have moved out of favour, sound odd (although I love the sound of both), and Honda have phased them out. The death knell has been sounded, so enjoy them while they still exist.

I used to be a four-stroke only rider until I got my KTM 200EXC. How such a tiny, light lump can make so much torque and bring so many grins still amazes me.
 
Flukester said:
A 165kg modern superbike with a 1 litre v-four 2t engine, I rekon you'd be able to squeeze 250bhp out of it no probs, probably a lot more. The rush as it come on song and hits powerband would kick you straight off the back.
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Corrected for you...
:D
 
Flukester said:
I had the orig KR1 which was also pretty good..
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i find it amusing how close our biking histories are!


I too had a KR1, but it was a KR1-S. Wicked little bike - fastest 250 ever i think (140mph?) tho mine topped out at a more realistic 130.

2-strokes are ace, and i'm sad to see their demise. Before my KR1 i had a TZR125, turned the powervalve round, and wahey! Great fun (at the time)
 
Kinda related but Bike magazine has a several page feature this month lamenting the demise of the 250cc class, one part of it looks at the future of 2-stroke (mentioning the lotus engine), seems with modern technology they can make it pretty much as fuel efficient as a 4-stroke, but with better emissions and much more power/torque.

Even hints that it's possible that there may be a resurgence in them due to the EU emissions regulations etc...
 
I would love a return to 2-strokes as from an engineering point of view they are brilliant. Simple, powerful, easy to service, cheap to make and with the right development clean and efficient too.

They got an undeserved reputation for blowing up due to the tight tolerences of race bikes and lack of maintenance from most owners. Day to day 2-strokes would last forever, just look at 2-stroke scooters for good reliability.

A modern 400cc 2-stroke could weigh 140kg in road trim fully fueled and push out 110bhp without much trouble while retaining reliability.
 
Can still remember my import RZ250 YPVS. The way it used to say hello when you turned the ignition on by moving the powervalves. The way it used to lift the front wheel when you hit 6000rpm and the powervalves opened up and the way the frame used to flex when thrown around hard!

My mate started on an RD125(parallel twin, no the old single), then got an RD250, then RD350 then RD400. Followed by a SS tuned 350LC and finally an RD500. The 500 was in the classic Marlborough paint job as well. The smell of Castrol R was addictive.

I always lusted after either an NS400R or an NSR250R with pro-arm rear end.

some where in the loft ive got some pics of a YammaGamma. 350YPVS in an RG250 frame. Used to see loads of 2-squeaks at Devils bridge in the late 80's, one bloke even turned up on a road legal TZ350. The noise from the pipes was enough to make the hairs on your neck stand up from nearly a mile away(good old days when noise regs werent as tight as tight)

Damn, makes me realise how old im getting :eek:
 
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