DAVO

hi friend ive had both 2 & 4 stroke with 4 the power is there from start 2 finish with 2 u have 2 wait for the power band 2 kick in then its hold on tight also with the 4 they will go up hills all day long where the 2 may fade it depend on what suits u

dirtbikenut

Think about this:
If you never knew anything about what a 2 stroke was but this new 3 stroke technology was just introduced.

-Same HP as a 4 stroke ( or VERY close).
-30% weight savings; much better HP per to weight ratio
-40% (approx) less moving parts
-much cheaper to maintain (up to 50% less)
-lower entry cost (the machine/bike will be cheaper).

What would YOU buy?

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Thompson Racing Suspension

tigmaster

i like the 30% weight savings. why? its around 4% weight savings on mx series bikes. also in the 250/450f class the 450f's are producing about 4 more hp. also 4 strokes now rev higher than 2 strokes.

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dirtbikenut

Yep, you're correct, it's more like 8-12 lbs (whatever 4% works out to) if you're comparing 250 2 stroke with a 450 4 stroke. But you need to keep in mind there are many more rotating parts in the 4 stroke which lends itself (this is basic physics) to want to keep moving in a straight line; therefore, the bike will not want to change direction as easily as something with less moving parts (again basic physics and if you don't believe me go play with a toy gyro for a while).

It's not all about weight, but the physics behind what that 4% will do when it's rotating at a high rpm.
I love 4 strokes too, I've owned many of them, but when the 2 strokes came out they were a technological leap. The first MX bike were 4 strokes but the newer and 2 stokes with their weight advantages and less inertia won out over the 4 strokes. So, we are now attempting to build a light and powerful 4 stroke and with that comes using lighter parts, making it rotate at high rpm and losing reliablity (unfotunately).
This isn't a bad thing, it's technology attempting to make something better and in a few more years maybe we can get more life out of our 4 strokes as we did with our 3 strokes (keeping in mind someone that does scheduled maintenance when specified).

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Thompson Racing Suspension

tigmaster

ya, that is really true. those parts really do make a difference. maybe you have stumbled onto to the answer to this through your years of knowledge, but do you know the reasoning behind hondas "balancer" in all of their engines. if you are not familiar, its a geared up random spinning piece of metal. its in all of their engines and apparently helps keep them running smoother, but im not sure if its just required due to the uni-cam design or if there is some other magic behind it. i understand a crankshaft balancer but this is not the same and only weighs maybe 8 ounces.

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