Exploding Flywheel?

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Justin9

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It may also explode at idle...

With the gx200 clones that I race... we consider them safe up to about 6,000.... after that, it's questionable...

With the Briggs 5hp flathead, we would run the stock cast flywheels up to 7,500 safety, then over that, you'd move to a billet flywheel...

With the gx200 flywheels, a common problem is the magnet is screwed into and glued onto the wheel, and there is a gap between the magnet and the wheel where the magnet sits, what happens alot of times is the coil will come loose and fall down onto the magnet, when the gap comes around, the coil falls into that then hits the magnet, that's when all hell breaks loose... supposely, one of the importers of the "racing" gx200 clones is having China make a Steel Billet flywheel that should help this problem for the clones...
 

Doc Sprocket

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I sure as he// ain't gonna sticky it! I might barf, though.

Although, I do enjoy reading stuff that suggests that once you hit 3601 RPM, the 'wheel's gonna go off like a nuclear warhead, killing everyone in a 36-block radius and shifting the earth on it's axis!
 

Russ2251

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A guy at oldminibikes.com told me I was going to send my "man parts to Jupiter" if I continued to run my engines ungoverned. He went on to say that many injuries have occurred and lives have been lost.
I asked him to send me a link in regard to this phenomenon.
Needless to say, I'm still waiting for any response.
You will be hard pressed to find ANY empirical evidence.
 

Bluethunder3320

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wow. i have an extra clone flywheel. if i had a machine to measure the RPM it takes to blow up, id be willing to do it.

im surprised no one has taken a $5 clone flywheel and RPM tested it, and videotaped.
 

Doc Sprocket

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Blue, I proposed this awhile back but never did it because it wouldn't be a true test. I WAS willing to use an electric motor to belt-drive my old Tec h60 with the spark plug out (to make it easy to spin at high speed) with my laser optical tach to measure speed. I would change pulleys to achieve progressively higher speeds until it failed.

Here's the problem- With the Tec being driven by another motor, the natural harmonics and balance of the engine do not exist. The compression isn't there, the power stroke isn't there, the natural forces aren't there. In my own humble opinion, this test data would mean nothing- so I didn't do it.
 

Bluethunder3320

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yeah thats true. i have held a 6.5 clone WOT for about a minute straight before, though, no load, and nothing happened.
 

Justin9

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i believe about two years or so ago, ARC did take a stock clone flywheel had spun it to about 10,000 before it blew... this was down at a lab that is setup to test things of this nature, and not actually done at ARC...
 

Bluethunder3320

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every flywheel is probably a little different and it depends on their history of getting hit with a hammer, pryed off, left outside, left in the cold than hot summer than cold again, etc, hard to call it.

10K seems promising that ill be OK at 5K.
 

Justin9

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Oh, completely true... and that's just one or two wheels they sent off for testing... I agree... 5k or 6k (like we run them) seems to be ok and should have no problem using that as a base...
 

Doc Sprocket

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Flywheel defects and damage aside, I would be much more concerned about the reciprocating assembly...

Frankly, with the right defect, your spark plug could separate and blow out, killing the guy behind you. In fact, let's start that as a new myth!
 

Wheel-Horse

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I am not into go-karts, but garden tractor pulling. I have personally witnessed a flywheel blow-up and it was not pretty. The engine was turning about 5000rpm on a cast flywheel. In tractor pulling, all clubs rules are over 4000rpm a billet steel flywheel is mandatory. Here is a few pictures of a tractor that's cast flywheel exploded. Just don't want to see this happen to anyone else.
http://gardentractorpullingtips.com/flywheelbreakage/flybreak.htm
 

B man

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well NO ONE can say it cant happen. and there have been instances where it has,but usually do to un-proper maintenance. such as extreme engine abuse.
 
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