DS650 Broken Crankshaft at Flywheel
#1
My 2001 DS650 crankshaft sheared at the flywheel side of the motor, flush with the crankcase. When I took the side cover off, the flywheel fell right out. There are no signs of excessive heat or bluing or grooving at the shaft. There was no detonation. It just broke off. The ATV was a new about 14 months ago, but has only been ridden half this time.
Has anyone ever heard of this happening?
I heard of a guy who had a broken shaft at the clutch on his first ride.
Could this be a defect in the crankshaft? Hardness of the material out of spec?
I noticed the flywheel is very heavy. I am wondering if the inertia was too high. If I replace the crankshaft how do I know this won't happen again? I'm thinking I need to lighten the flywheel.
Should I just order a new crankshaft & rod assembly from the dealer or is there an alternative?
Has anyone ever heard of this happening?
I heard of a guy who had a broken shaft at the clutch on his first ride.
Could this be a defect in the crankshaft? Hardness of the material out of spec?
I noticed the flywheel is very heavy. I am wondering if the inertia was too high. If I replace the crankshaft how do I know this won't happen again? I'm thinking I need to lighten the flywheel.
Should I just order a new crankshaft & rod assembly from the dealer or is there an alternative?
#2
RPMs, vibration, and harmonics are usually the culprits behind crankshaft failures. I would highly suggest you have your next one dynamically balanced with the amount of horsepower and rpm you turn. I would be interested to know if anyone makes a better aftermarket crankshaft for the Rotax engine
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Scoobie,
Your signature says it all. 100RWHP!?!? Holy bagezers dude what did you expect?
The tortional loads put on that part of your crank from the (much quicker) rise and drop in RPMs, coupled with the weight of the flywheel will definately have an effect on the crank. This is one of the reasons for lighter flywheels on race engines.
Until someone comes up with a stronger crank, lightening your flywheel is the only way to avoid a re-occurence. Of coarse this will effect your wattage output but that is a small price to pay for a longer lasting engine that puts out more then double the intended RWHP.
PS.
If the rotor was not sraight on the crank, It would have failed sooner and you would have noticed a hell of a vibration. With the taper of the two parts its impossible to put it on crooked unless one was made wrong.
Your signature says it all. 100RWHP!?!? Holy bagezers dude what did you expect?
The tortional loads put on that part of your crank from the (much quicker) rise and drop in RPMs, coupled with the weight of the flywheel will definately have an effect on the crank. This is one of the reasons for lighter flywheels on race engines.
Until someone comes up with a stronger crank, lightening your flywheel is the only way to avoid a re-occurence. Of coarse this will effect your wattage output but that is a small price to pay for a longer lasting engine that puts out more then double the intended RWHP.
PS.
If the rotor was not sraight on the crank, It would have failed sooner and you would have noticed a hell of a vibration. With the taper of the two parts its impossible to put it on crooked unless one was made wrong.
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