Flywheel explode

[fatjet87]

Been racing these 212 predators going on 2 years now. I've got 2 karts I run. Run 1 in a box stock class and the other in stock appearing. I run the stock flywheels that came on them when purchased from harbor freight. I don't have a tach on either one of these karts so I can't exactly tell you how many rpm's their turning.
I can tell you on the stock appearing 1 that I changed out my valve springs for some 19lb ones I believe that's what they are due to floating the valves. First thing I did after buying engines was removed the blower schroud and epoxied around the magnets. Then sanded down the excess.
Can someone explain this to me in laymans terms. How does the stock cast iron flywheel explode when under high rpm? Is it just made cheap to keep costs down or is it because they are manufactured by casting? Like I said
I've raced these engines with the stock flywheels on them and been side by side with them down the straights running all out. I'm not worried or scared one may blowup and pierce my skull, cause I'm wearing a helmet and chest protector.
Don't get me wrong I'd love to buy one, but currently I don't see the point. I also think if it doesn't blow apart the first time you really spin it up, then your good to go, it passed the test. I know I'm gonna get a lot of crap over this, but it's just my honest opinion after racing these predators 2 years.

 

[Kart43]

Any and every moving part is capable of failure, a heavy rotating cast part has the highest chance of failure. You cannot see the stress points, voids and flaws the first spin up is not an indication of integrity. Helmets and chest protectors will not be enough in this violent attack. The face shield will only provide evidence of where you got struck, what about the innocent person standing on the side. Good luck.

 

[youngengines]

Been racing these 212 predators going on 2 years now. I've got 2 karts I run. Run 1 in a box stock class and the other in stock appearing. I run the stock flywheels that came on them when purchased from harbor freight. I don't have a tach on either one of these karts so I can't exactly tell you how many rpm's their turning.
I can tell you on the stock appearing 1 that I changed out my valve springs for some 19lb ones I believe that's what they are due to floating the valves. First thing I did after buying engines was removed the blower schroud and epoxied around the magnets. Then sanded down the excess.
Can someone explain this to me in laymans terms. How does the stock cast iron flywheel explode when under high rpm? Is it just made cheap to keep costs down or is it because they are manufactured by casting? Like I said
I've raced these engines with the stock flywheels on them and been side by side with them down the straights running all out. I'm not worried or scared one may blowup and pierce my skull, cause I'm wearing a helmet and chest protector.
Don't get me wrong I'd love to buy one, but currently I don't see the point. I also think if it doesn't blow apart the first time you really spin it up, then your good to go, it passed the test. I know I'm gonna get a lot of crap over this, but it's just my honest opinion after racing these predators 2 years.

Thats kinda like driving with no insurance... I have seen them come apart.. I'm not taking that risk

 

[alvin l nunley]

Any and every moving part is capable of failure, a heavy rotating cast part has the highest chance of failure. You cannot see the stress points, voids and flaws the first spin up is not an indication of integrity. Helmets and chest protectors will not be enough in this violent attack. The face shield will only provide evidence of where you got struck, what about the innocent person standing on the side. Good luck.

Very good advice. Short and to the point.

Although it is a rarity, McCullough flywheels have lost fins. I personally have never seen it happen in the 15 years that I raced McCullough's, but it can happen, and with disastrous results. One person even died.

I don't know where it happened, but at an enduro race, one driver failed to come in after the race. A search ensued and they found him lying, dead, in his kart in a wooded area off the side of the track. A flywheel fin had broken loose and entered his head underneath the edge of his helmet, killing him. A tragic rare occurrence yes, but it happens.

 

[mike97760]

To me, buying an aftermarket flywheel for these engines is no different than buying a helmet, and I look at it solely as a protection, not a performance, item.