Are modern two strokes really better?

[Boyracer]

Just wondering are modern two stroke MX bikes really better than say a CR250RF 85 model?
Do modern engines really make more or better power than water cooled engines from back in the day?
From what I can work out there doesn't seem to be much of a power advantage, sure suspension technology may have improved but a good rider on a VMX should be able to be competitive with the modern iron.
Any thoughts?

[allan hughes]

2 strokes do produce power
i have a cr500 which i love to race flat track
the power is exillerating
4 strokes have engine braking
2 strokes do not
end of debate

[Mike52]

Just wondering are modern two stroke MX bikes really better than say a CR250RF 85 model?
Do modern engines really make more or better power than water cooled engines from back in the day?
From what I can work out there doesn't seem to be much of a power advantage, sure suspension technology may have improved but a good rider on a VMX should be able to be competitive with the modern iron.
Any thoughts?

Wondered that myself.
Looking at videos of early 80,s 500cc World championships they look to be insanely fast.

[oldyzman]

IMO, modern 2 stroke dirt bikes do have better power than say the mid eighty's. But a fully sorted mid 80's 250 compared to a run of the mill modern 250 will probably perform better, but not for longer.... I do hear that a late model yz250 is quite well squished and tuned off the floor though...
Brett

[80-85 husky]

the 300 ktm is a bit sharper than the 400 husky. the powervalve allows its useful range to run from idle or less RPM to 7000 (I think that's about where they sign off.)
the 400 will match it in a drag race (must check this, its a gut feel statement). the 400 will fluff out and die at about 1000 rpm under strain. just wont pull cleanly and is quiet till its gets some velocity in the intake.

the broad spread of the kato engine is definitely better and easier to ride than the 400.

in answer to the question I say yes, the engines are better but I don't thinks there is any more power (of a significant amount!)

the brakes are the biggest advantage and will always see a modern hammer a old dunger on a track although watching the number of "over the bars and tuck unders" on utube, I don't believe the geometry of the modern fourstrokes is better than the older bikes. Much more steady and easy to ride than the new "nervous nellies"

[Nathan S]

Yes, new ones are better.

I've got a 2013 Beta 300. Straight out of the box, it has excellent jetting, beautiful power curve, plenty of power, it hardly vibrates, it always starts, and it's still like new with 1,500km on the clock.

That's stock.
An 80s 500 will outrun it in sheer grunt, but is a complete pig to live with in comparison.


A properly built 86+ CR250 would probably be in the same league, but only after you've replaced and/or modified the carb, ignition, exhaust, head, piston, barrel - basically by turning it into a modern motor... You still would be stuck with a much more difficult-to-live with power valve, no electric start, and more vibes.


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Old bikes can be competitive with moderns. But as an all-round, do it all regardless of conditions race bike, you would ALWAYS pick the modern.

[Ted]

Modern bike makers have realised that they have built in too much rigidity in their frames and are actually going backwards to put more flex in them.

[Paul552]

Modern bike makers have realised that they have built in too much rigidity in their frames and are actually going backwards to put more flex in them.

Very common comment re rigidity when watching mx Dungey on the KTM (not as harsh on the body as the jap bikes)
Many riders comment the flex/feel of frames.

[Nathan S]

Twin spar aluminium frames don't work for 2T dirt bikes. They're semi-OK for 500s that have the extra weight and torque, but if you think of a 2T dirt bike that handles well, it probably has a steel frame...

But the question was about motors rather than the whole package.

[VMX247]

Modern bike makers have realised that they have built in too much rigidity in their frames and are actually going backwards to put more flex in them.

Very common comment re rigidity when watching mx Dungey on the KTM (not as harsh on the body as the jap bikes)
Many riders comment the flex/feel of frames.

Isn't that why KTM has stayed with steel frame.

Try that CR in a modern frame.
Cheers us2

[Kane Mcguire]

I have raced a 2011 yz250 and 1982 husky 250 on modern tracks for 3 years and the big difference is when you get out of shape on the modern bike it more often rides out of it safely but when you get out of shape on the old bike its all over!

[evo550]

A couple of years ago (2010) I had a 10 Ktm 250 sx and a 86 Husky 250 and nothing on the Husky even came close. Rear suspension on the Husky was good, but that's about it.
Far as I'm concerned they are chalk and cheese.
2012 I had a 87 cr 250 and a 2013 Ktm 300 exc, again same deal, the Honda was a much better bike than the Husky, but neither can compare to a modern.

[Tim754]

 My observations are that modern 2T bikes do have the edge in all engineering and mechanical departments. They just don't have the "quaint quirky" looks of old ones.... Tim754

[evo550]

A couple of years ago (2010) I had a 10 Ktm 250 sx and a 86 Husky 250 and nothing on the Husky even came close. Rear suspension on the Husky was good, but that's about it.
Far as I'm concerned they are chalk and cheese.
2012 I had a 87 cr 250 and a 2013 Ktm 300 exc, again same deal, the Honda was a much better bike than the Husky, but neither can compare to a modern.

It would also appear I can time travel....

[Tim754]

"It would also appear I can time travel...."   or perhaps multitask Evo like drink beer whilst ya type Cheers  and crack another!