True 250 class - 2-stroke comeback?

[bills442]

heh, well not free!. I should have said "virtually nothing" I didn't want to quote a number since it costs so little I can't remember what I spend each time I do it. If it was like $500 or $600 you'd better believe it would be on my "spending radar" memory, lol.

[bills442]

YZ250 equals 46hp. 250f's 35-37hp. Have no idea how high the factories get the 250f's up to.

well, based on my car experience, I imagine there's really no limit to how much horespower you want to produce with a 4 stroke ... just keep upping the compression and RPMS and use more and more exotic metals in the valvetrain. All depends on how much of a "grenade" you want to build. Great stuff, if you've got unlimited $$$ and someone else doing your wrenching, lol.

[DMC707]

And if they still made open two strokes they would be far superior to the 450 fours. True they did improve the four stroke breed by leaps and bounds. But two strokes will always rule all things being equal.

I have one of the last years of KX500 ('03) and a new YZF 450. The 500 will outrun the sreoker in a drag race, but thats it --- vibration, and arm pump are much more of a factor on the big bore 2's than the 4's.

I think the bigger bikes and open classes are the place the 4 stroke will continue to dominate (they still have the open class in Europe). You can easilly make 62 or 63 hp's in a package that is easier to ride than the 2 strokes by far.

That said, my KX uses 1988 trchnology and the CR500 uses 1989 technology, so its not a fair comparison. People who have tested the Service Honda CR and KX conversions still say they have not killed the vibration either. New R&D could probably fix the 500 2 strokes problems, but its really rolling the dice for the factories.

I am sold on the big strokers for making big power I know a 500 2 stroke could click over 75 or 80 hp's quite easilly, but unless your name is Jeff Stanton or David Bailey, you probably can't use it.

That said, my big 450 will be my primary racing scoot, but if this economy ever cleans itself up --- i would love one of the SH KX500 conversions for a fun bike

[mxkid12]

Here you go , for some inspiration!

Watch these helmet cam vids 2x vid.

2stroke only MX race.

First Moto

http://www.youtube.com/watch?v=V1XaE...eature=related

2nd Moto

Watch it on high quality & crank up the volume to hear the sound properly. Those GoPro cams are awsome. 2t's are awsome!

this video is sweet and you have to love the sound from same person

its at thunder valley

[why_zed]

I my KX uses 1988 trchnology and the CR500 uses 1989 technology, so its not a fair comparison. People who have tested the Service Honda CR and KX conversions still say they have not killed the vibration either. New R&D could probably fix the 500 2 strokes problems, but its really rolling the dice for the factories.

A 500 2 stroke is a massive motor, be like putting a HO 750-800 4 stroke in a dirt bike.

A 300, 325, or 350 two stroke with an engineered PV and expansion chamber would have a better chance of keeping up with today's 450Fs.

I had a 380 KTM that was sooo sweat, suspension and abilities held me back, motor could be (like a 450) put in 3rd gear & do the whole track.

[dtkiko]

what year was this southwick event when the great doug henry was still riding the blue alum-frame 250?

http://www.youtube.com/watch?v=KyuUgESTDjQ

[CaptDan]

From the ’09 Yamaha MX / Off-Road brochure:

“We love the smell of premix in the morning.”

“Ready to rip from idle to redline and inexpensive to maintain, the YZ two-strokes are here to stay.”

“Rumors of the two-stroke’s demise have been greatly exaggerated. In fact now that the AMA rules have changed to allow 250cc two-strokes to compete against four-strokes in Amateur competition, there is no doubt we’ll all get to hear that sweet sound for years to come.”

“We’re there for you, ahead of the pack, two-stroke or four.”

The bikes are still being made for other markets, yet the 4-strokes are still out-selling the 2ts here in the U.S.....Only way to truly MAKE the OE's bring them back is to stop buying new 4t's !!

From what I've been seeing lately, that has already started to happen.

Unsold 4-strokes on showroom floors and in blow-out deals on eBay.

Most of the 2-strokes were spoken for and sold before they even reached the dealerships.

The Japanese OEMs are losing customers to the European brands who offer modern 2-strokes in a variety of displacements. (Our local dealer said that the 300cc bikes are KTMs best sellers.) ?

Yamaha could easily do a light re-fresh on their 2-strokes (their current bodywork is seven years old!), and maybe offer 150 & 300/325 motor kits through their accessory catalog.

I believe THAT would spice up the market!

[mxjosh]

I would think all them 4strokes on show room floors might have to do with the economy as well. Its also a lot easier to sell out of something that there isn't a lot of. Seeing how KTM and Yamaha are the only ones selling 2 strokes there's no competition.

[why_zed]

I would think all them 4strokes on show room floors might have to do with the economy as well. Its also a lot easier to sell out of something that there isn't a lot of. Seeing how KTM and Yamaha are the only ones selling 2 strokes there's no competition.

Yes, if you know that you want a 2 stroke, the options available have been thinned out. Blue or orange at the moment.

[Poppy_103v]

I just find it ironic that Yamaha lead the 4stroke revolution and now they are one of the last bastion's of the 2t.

[The Spanky]

I just find it ironic that Yamaha lead the 4stroke revolution and now they are one of the last bastion's of the 2t.

That's because Yamaha, unlike AMA Racing and Honda, never intended to eliminate two-strokes, they just wanted to have more products to sell.

[CaptDan]

I would think all them 4strokes on show room floors might have to do with the economy as well.

No doubt.

Another strong point of the 2-stroke -- lower initial cost, and MUCH cheaper to maintain (than modern 4-strokes). ?

[scooter42]

A 500 2 stroke is a massive motor, be like putting a HO 750-800 4 stroke in a dirt bike. ?

A 300, 325, or 350 two stroke with an engineered PV and expansion chamber would have a better chance of keeping up with today's 450Fs.

I had a 380 KTM that was sooo sweat, suspension and abilities held me back, motor could be (like a 450) put in 3rd gear & do the whole track.

Even heavily detuned, 500 2T is more motor than most could handle and far more torque and HP than a 450 is capable of in a highly tuned state. A 2T 300-350 could easily be tuned to have a smooth power band and very rideable on par with any current bike. I watched my buddy on his RM 265 pull holeshot on 450's with equal riders repeatedly with no more tuning than a pipe and flywheel. Cheap fast easy to ride.

Think about this for a sec. If my 3.5 liter V6 Altima was a 2T, it would have a conservative 420 HP and would weigh way less. A standard V8 chevy would have over 600 HP and would weigh less than any small block out. Just take for example 6 CR500 jugs at 500cc. As a lightweight smaller 3.0 V6 that would have 360 HP! This is detuned and dependable HP. Any of us could send our car motor to Gorr and get 1000 HP for a few bucks! ?

[The Spanky]

Even heavily detuned, 500 2T is more motor than most could handle and far more torque and HP than a 450 is capable of in a highly tuned state. A 2T 300-350 could easily be tuned to have a smooth power band and very rideable on par with any current bike. I watched my buddy on his RM 265 pull holeshot on 450's with equal riders repeatedly with no more tuning than a pipe and flywheel. Cheap fast easy to ride.

Think about this for a sec. If my 3.5 liter V6 Altima was a 2T, it would have a conservative 420 HP and would weigh way less. A standard V8 chevy would have over 600 HP and would weigh less than any small block out. Just take for example 6 CR500 jugs at 500cc. As a lightweight smaller 3.0 V6 that would have 360 HP! This is detuned and dependable HP. Any of us could send our car motor to Gorr and get 1000 HP for a few bucks! ?

You have some valid points, but multi-cylinder two-strokes in a "V" configuration lose some of their weight advantage because they require two cranks and two rows of crankcases. Each cylinder has to have it's own crankcase. Unless of course we're not talking about crankcase-scavenged two-strokes. But then you have to add a valve train, like Detroit Diesel two-stroke diesels.

[mfinDRZ]

Yamaha makes a 3.3 liter 300hp 2t outboard- put that in a small car.

2StrokeNut already has posted a sand rail with a 2t V-8,

https://www.thumpertalk.com/forum/showthread.php?t=600302

it sounds loud.

[seanmorris]

I just noticed this little bit on cycle news...

Cycle news article

and this on Racer X

Racer X article

Take a look at the eighth paragraph...

"Operationally, the 2009 Women's Class technical regulations will be the same as the men's 250 Class (formerly AMA Motocross Lites)..."

Could a class name change mean new life for our beloved 2-strokes?

I hope so

Sean

[KX250 rider 2005]

I live in england and they stopped making kx 250 2t here in 2008

[RCannon]

I just noticed this little bit on cycle news...

Cycle news article

and this on Racer X

Racer X article

Take a look at the eighth paragraph...

"Operationally, the 2009 Women's Class technical regulations will be the same as the men's 250 Class (formerly AMA Motocross Lites)..."

Could a class name change mean new life for our beloved 2-strokes?

I hope so

Sean

I hope your right, but I took it as the nail in the coffin. Do they nail coffins shut? Is so, why?

Anyway, I figured the name change was going to write off the 250 2t as if it never existed.