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Street bike vs dirtbike engine reliability..confusing..?

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I already posted this on general forums, but just wanted to see what you guys thought.

Just out of curiosity I was wondering how inline 4 street bike motors can rev so high (for example a yamaha r6 redlines at 16,500 rpms) and hold up for many miles without wearing out the piston and rings? A modern single cylinder 4 stroke dirtbike motor can rev to at most about 14,000 and even in recreational use for trail riding the piston and rings have to be replaced quite often, and that's with keeping the air filter cleaned and the oil changed frequently! What is so different in design that allows a street bike motor to last at high rpms, running the same high compression pistons, etc. and not need to be rebuilt like a dirtbike? Is it because of having more cylinders, makes for less stress on just the one piston or a dirtbike or what is it?

Thanks.

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It's putting out 4 X the work that's why. Think about it.... How much is 1 firing piston working harder than 4 of them gettin' it done? Not to mention, the street queen isn't sucking dust and roost. It isn't working as hard.

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Street only, will show benefits in longevity over dirt only, the question is it enough to be usable on a particular model. Generally anything that will hold up offroad will yield 10x the time on the street. Assuming you gear it for the street.

It would be nice to see a KTM that didn't come from the factory burning oil or have brakes leaking fluid, and have a good 40 or 50,000 street miles on the original motor, I think that would be great to see. Until the simple stuff is addressed, road longevity might be hindered.

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It's all about the level of tune. Modern 250f motors are putting out almost 50 hp! All while being as light weight as possible and sucking in more dirt than a street machine.

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Street only, will show benefits in longevity over dirt only, the question is it enough to be usable on a particular model. Generally anything that will hold up offroad will yield 10x the time on the street. Assuming you gear it for the street.It would be nice to see a KTM that didn't come from the factory burning oil or have brakes leaking fluid, and have a good 40 or 50,000 street miles on the original motor, I think that would be great to see. Until the simple stuff is addressed, road longevity might be hindered.

I've owned multiple Ktms and neither of them came burning oil or leaking fluid :confused:

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Street only, will show benefits in longevity over dirt only, the question is it enough to be usable on a particular model. Generally anything that will hold up offroad will yield 10x the time on the street. Assuming you gear it for the street.

It would be nice to see a KTM that didn't come from the factory burning oil or have brakes leaking fluid, and have a good 40 or 50,000 street miles on the original motor, I think that would be great to see. Until the simple stuff is addressed, road longevity might be hindered.

None of my KTM's ever leaked brake fluid or burned oil.

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