Two Strokes Have Had Their Day

I think it is good to have new direction. I like the idea of a fuel injected four, next generation may be turbo aspiration, then maybe a blower in the near future? Can you imagine the belt for the blower hanging out the engine? Whaaaaa! You guys CAN'T tell me that you wouldn't like to see that! A fuel injected, blown YZF450. Who knows?


Yes we have the right to choose, but not at someone else's expense. Yamaha and Kawa etc, have the right to pick and choose to make any bike they want to make, and you can't do jack about it. It's arrogant to assume the role of director of someone else's business. The majority want 4 strokes not 2, so they make em.

Two strokes.. they have had their day. Remember just like the 2 stroke started out in its infancy, no travel in suspension, a complete dog to start the bastard, shit rattling off all the time, blown gaskets, broken this and that.. it's all part of the game that we LOVE! As a small Eng. mechanic I've seen (and thrown away) more two strokes in the shop for repairs than 4s so don't argue about 2 strokes being a sound Eng., that's just in theory.

In reality the 2 stroke is prone to human fault. Forgetting to put oil in the tank is a big one, smashed pistons, scoured cranks, rods and bores. Piston and main bearings you have about 30 seconds to remember that oil has been left out of the equation at start up of every top up. What about seals that don't last very long due to the fuel that is constantly in contact with all the rubber seals in your 2 stroke? This may sound trivial until you have to pry the pricks out!

The only thing a 4 stroke will have wrong with it (in the majority of cases compared to a 2 stroke) is the rings have worn down and need replacing - that is the majority of probs. for a 4 stroke. These are but a few of common problems I have experienced over the years in the shop.

You can't argue the point either of being ripped off with fuel injection, even a 2 stroke has electrical goods on board - the CDI unit - which is a source of problems. I bet the agitators of this argument were pissed about the introduction of this unit as well.

Four strokes are good now, but will get better as the years progress, to not see this is a show of youth and inexperience. Remember that he who dares wins, and the yzf has dared and has won. It just gets better from here on...

Comments for Two Strokes Have Had Their Day

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Sep 08, 2012
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2 Beats 4
by: Anonymous

the bottom line -- my kids 2 stroke 80 will blow the doors off 4 stroke 250.

Sep 24, 2011
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Huh?
by: nick

You're a small engine mech? For what? Lawn mower's and weed eaters? You don't do anything in power sports or you would have said "powersport mech".

I have seen 10 year old 2 strokes with no bottom end rebuilds that ran like tops. I am a diesel tech by trade, even I know and can see that a 2 stroke is a better engine. Less moving parts, higher power to weight, better performance, more reliable (in my experience). When you have an engine that has not seen heavy development / refinement in the last 10 years and they can still compete with fuel injected 4-5 valve engines of twice the size there is something to say about that.

Look at ski doo's new e-tec sleds. 800cc 163 hp that's what the future is. Imagine a 250 with e-tec (only adds 2-3 pounds) would make over 50 hp with a better power band, bottom end, and better fuel econ. Now imagine a 500 with e-tec - 100 hp would be possible with some other refinements (atac ignition comes to mind).

2 strokes are the future. Ktm and a host of other European manufacturers know this but it seems the Jap makers don't. Hmmm..

Sep 21, 2010
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Really?
by: Matt

You are a small engine mechanic, yes? Most small engines are running in a very mild state of tune. This means that you may not see many 400cc lawnmowers in your shop because they are only building about 6 bhp. Think about trying to get that Briggs motor to put out 7 times it's current power. Guess what happens. Yardsale.

Two strokes hold up better to high rpm operation because of their lack of valve train. They handle high power output better because each combustion cycle needs to only be half as violent.

Think about two 250cc engines. One is a two-stroke and the other is a 4-stroke. To make the same amount of power at the same rpm, the 4-stroke must fire twice as hard because it fires half as often. This puts enormous stress on the bearings, not to mention the ridiculous valve geometry required to get that much needed air/fuel charge into the combustion chamber.

Bottom line? 2-strokes are the shizznit.

Sep 02, 2010
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2 T Rule
by: Todd

I have a 2007 YZ250 2 stroke, and just recently rode a brand new, 2010 KX450f - fuel injected, and the computer remapped to its 7th mode (like spastic nutcase mode), and I was seriously disappointed. It was so much heavier. Compression braking was shitful, it was such a burden, and it was not any faster than my 2 stroke.

MY YZ250 also has a 15 tooth sprocket on the front, stock is 12 tooth. We raced down a 300m straight and we were even in acceleration, mine flogged it in top speed. Could you imagine if I had my 12 tooth on the front? 450 wouldn't be anywhere near me.

I don't understand the big hype about four strokes. They're also a major pain to start. What a drama trying to find top dead center and kicking it 15 times before it goes. My YZ250 you can kick it over with thongs on and it goes first kick.

Aug 28, 2010
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What?
by: Shaun

Sorry mate, you can't tell me it's cheaper to rebuild the top end of a 4t than a 2t? Not to mention you need larger displacement to compete with its 2 stroke brethren (250s vs 450s). And the only reason why 4 strokes have caught up technologically is because that's where all the research and development is going - not because they are better, but because they know people have to pay absurd amounts of money to keep them together, also known as money making.

At least we still have European manufacturers developing 2 strokes. Now I'm not sure what 2 strokes you've been riding or how well they've been kept, but there's literally no 'shit that rattles' as you've said because the engines are so simple and effective. Just have a look at some of the intelligent 2 stroke posts by others.

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