My friend rode his x4 150 in a parkinglot yesterday to practice for the up coming MOM motard race. Did'nt take long and snap...thought he may have sucked a valve but after further inspection. The engines junk...broken connecting rod, hole in the flywheel, nothing was left unharmed. Obviously from over revving????? Is this common? The bike did have 2 seasons on it..but still
yx 150 broken crank
stevos50nuts
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My friend rode his x4 150 in a parkinglot yesterday to practice for the up coming MOM motard race. Did'nt take long and snap...thought he may have sucked a valve but after further inspection. The engines junk...broken connecting rod, hole in the flywheel, nothing was left unharmed. Obviously from over revving????? Is this common? The bike did have 2 seasons on it..but still
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It is not a 2 stroke!!!!!!!!!!!!!!!!!
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ROBINSONDB22 said:
What he said ^^^^^
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my yx150 is almost 6months old and i ride the piss out of it. no problems cause i ride it like a 4stroke is supposed to be ridden. it's called torque. oh and it gets lots of tlc.
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I think he thought he was on his F6
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yea i have a yx150 motor too and the cam bearing decided to disappear and well it dropped a valve broke the rocker arms send a ball through the head and decided to take the piston and stuff along with it. Some of the YX motors last, some of them are lemons. Thats just my opinion tho. For some reason when you here them at the race they all have that rattleing noise when they are coming at you like the piston is floppin around or something. Kinda like a 110 motor that is about to blow up.
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stevos50nuts said:
Maintenance-free, no doubt. A neglected CRF450 will die just as spectacularly, if it doesn't get wrenched...
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your friend called me and pitster yesterday
(funny thing is i was being a smart a$$ and asked "is this a survey" ? )
a few cranks have broken , but its NOT common
we would like to see more motors comming in with ORK ignitions and these type ignitions to be more common as they lessen the overall stress on the cranks
(funny thing is i was being a smart a$$ and asked "is this a survey" ? )
a few cranks have broken , but its NOT common
we would like to see more motors comming in with ORK ignitions and these type ignitions to be more common as they lessen the overall stress on the cranks
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Splain that one please. The ORK I mean. Less stress how? You're talking to a duffus so make it simple.
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The Nutty Professor said:
i was talking to hack about the cranks breaking. sam has broken a few of them and hack said without the cover on when you rev the motor up to just before valve float you can watch the flywheel start wobbling cause the crank is bending due to the rotational mass of the flywheel. he seems to think the flywheel puts too much weight too far out on the end of the crank and if you saw where sams cranks were breaking it makes a lot of sense. hope some of that made some sense. i kinda know and kinda don't know what i'm talking about. hack could give a better explanation.
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Flywheel they ain't running IRK's with light slinger's.
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I believe the cranks are failing from only a few things, mostly rapid stopping, the engine screaming to a halt.Lets say your clutch basket is going out, and you keep riding it, then the gear wedges ontop of the crank gear, that instantly stops the engine, if you are at high speed, that side of the crank stopping and the other side trying to stop the big fly wheel (that is supposed to keep inertia spinning)tries to stop as well, just simply spins the end of the crank off!
Another culprit if when people that are good at jumping land hard on the gas when air speed and ground speed are not the same, as the wheel hits the ground, the engine rpms are high, and the traction Vs engine RPM ,can bring the crank to a very quick stop, also weakening or breaking the crank. By using the outer rotor it will offer less flywheel effect and minimize the failures on this side of the crank. In reality how many "race" bikes have a flywheel as large as these bikes? for a low power slow revving engine these would not fail, but with what they are doing now, no reason we do not see many more failures.Once outer rotors are in play along with improved clutches and baskets I feel most crank failures will be a thing of the past.
Another culprit if when people that are good at jumping land hard on the gas when air speed and ground speed are not the same, as the wheel hits the ground, the engine rpms are high, and the traction Vs engine RPM ,can bring the crank to a very quick stop, also weakening or breaking the crank. By using the outer rotor it will offer less flywheel effect and minimize the failures on this side of the crank. In reality how many "race" bikes have a flywheel as large as these bikes? for a low power slow revving engine these would not fail, but with what they are doing now, no reason we do not see many more failures.Once outer rotors are in play along with improved clutches and baskets I feel most crank failures will be a thing of the past.
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50rider340 said:
i have found that most of that noise is from the skid plate. mine cracked and it sounds like hell! i think these motors are great and have a ton of potential but are taking a long time to get the issues fixed. i think with ncc in the mix and everyone going over to china addressing the bad parts and supervising the production of the new model pitsters all these issues should be fixed. when the updated motors come off the line the calipers won't lie. if everything was fixed matt will be able to tell and we should all be getting a real quality part this time. all these problems were pointed out a long time ago but i guess it is taking some micro-management to get them fixed.
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NCC said:
that could all be true but the last one i saw break was in a left hand bowl turn and it broke off behind the flywheel against the case and there was no clutch side damage.
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correcttxkawboy said:
but lots of people hate IRK
so if the ORK was more avalible it would be a good choice and reduce crank stress
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