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Discussion Starter #1
just out of interest how much bhp does each cylinder on a zx6r produce foe example running on 2 cyliners and if year make any differece mines a 1998.

Thanks,

russ
 

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Theoretically you would divide the total power by 4 to get the power of each cylinder. In your case running on 2 cylinders would in theory give you half the power, but why are you only running on 2 cylinders? Are you trying to limit the power for learning purposes? Running a 4 cylinder engine on only 2 cylinders will cause the engine to hesitate because you will be working only 2 of the cylinders while the other two are along for the ride but since they are not firing (or not factored into the whole combustion process), your engine not run as smoothly and might vibrate since everything will be out of sync with 2 inactive cylinders. The crankshaft is divided equally between the 4 cylinders in order to make things run smoothly. If you look at the way the pistons are positioned in a 4 cylinder engine, all 4 cylinders will always be in one of the 4 different cycles of combustion but the two outter ones always always move up together while the two center ones will always move downward together even though they are off-cycle from one another. This keeps everything in balance, for instance as cylinder #1 is rising for compression cycle, cylinder #4 rises at the same speed and position as #1 but it is on it's exhaust cycle, but the fact that they are in sync is what keeps everything balanced. Running on 2 cylinders will induce an imbalance in the engine and impair its ability to rev high because you don't have the other two cylinders to "pull" the rest back around to complete the cycle as efficiently. You might think your engine is running smoothly but it is really struggling. Even if you only have 2 cylinders running, you will not even be getting half the power from the engine since your ability to rev a 4 cylinder engine running on only 2 cylinders will not be as high as if all 4 were firing since the 2 running cylinders have to pull the weight of the other 2 non running ones. Plus you'll also be wasting fuel since the carbs are still going to dump fuel into the 2 non running cylinders.
 

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Rough guesstimate would be 27.5 bhp (not at the wheel) factor in the two "dead" cylinders rotating mass and your looking at about 22-24 funtional hp, so 44-48 bhp with two cylinders. [:M74]
 

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Discussion Starter #4
so two cilinder would produce about 50bhp but it would be less at the wheel does anyone know what bhp would be produced at the rear wheel with only 2 cylinders

cheers,

russ
 

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Mate, I know the Speed Limit is sh*t here for us.....but switching two cylinders off sounds a bit harsh to me! ;)
 

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The power loss through the drivetrain is usually somewhere around 15%, so 50hp at the crank would give around 42.5hp at the wheel.

My experience is that 4-cyl engines really don't like to run on two cylinders. They will run fairly happily on three, but not on two.
 

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Man im totally out of the loop with this detuning of bikes for speed purposes/govt reasons. Are their new laws in europe regarding speeds of bikes and how much you can have to legally ride? Do they dyno your bike at the inspection stations...
 

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Discussion Starter #8
if you get stopped by the bill and you have a restyricted licence and they suspect you of not being with in that restriction they can take the bike and get it checked and i even think now they can call someone to come out an check it right there and then .
 

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Originally posted by rusty2541
if you get stopped by the bill and you have a restyricted licence and they suspect you of not being with in that restriction they can take the bike and get it checked and i even think now they can call someone to come out an check it right there and then .
if the police can stop you to check the restrictions on the bike, i think it would pay for you to own a bike that appears to be within regulations, not one that requires detuning to be legal. if your on an obviously small bike you wont have anything to worry about. i think you need to give up on this idea of reducing the power of a 100 hp machine down to 33 for the sake of getting it street legal. it will be much easier to just buy the appropriate bike. BTW how old are you? these posts seam very 16 years old to me.
 
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