New flywheels`- need input and help

[jesshamner]

I was riding down the road when I first spun a flywheel. I was in 4th gear and had been about 3/4 throttle for the last 2 miles when it died. It was giving it steady throttle and it just cut off.

[2000ex]

I have 3 machines and never once have spun a flywheel.

Wonder if there are any differences in the aluminum quality? There are large variances in rockwell hardness of our cams, wonder if the same could be said for the flywheels?

[Happyboy]

Jess, I would bet that yours was already damaged when you were on that road. These things are getting damaged then they just let go at different times.

[kdeal]

I think it may have to do with crankshaft vibration and harmonics. I'll bet that some of these cranks are not as balanced as others.

[cdsracer]

I went four years on my first flywheel, now I've spun two within the last year. All on the same engine, crank, etc... same rider, riding style and riding areas. The first one spun after coming off of a jump. The second one after doing a wheelie, and the third one in fourth gear on the flat about 90% throttle.

My wife and brother-in-law have never spun flywheels and ride on the exact same terrain I do (we play follow the leader in the dunes). My sister-in-law spun her first one in three years this weekend. She rides the same as the rest of us except no jumps or whoops, occasional wheelies. There is not much of a pattern here except that it sucks to get towed back everytime.

Manufacturing an entirely new flywheel with better materials seems like the best bet, although difficult. Modifying existing flywheels is next in line, probably much cheaper.
Has anyone thought of thermal treating our flywheels to harden the aluminum? Ideas on this??

[thedeatons]

I can understand your wanting to figure out why it is happening, but the simple fact is that it IS HAPPENING. Right now I would pay about $250 for a never spin flywheel, simply because I am over it. The little "fixes" are not working, and a new flywheel is at least $90, so after I buy that a couple times then I have paid for a completely new design that will never spin. I ride like I ride, and refuse to change my style or setup to overcome a faulty part. These are just like the crank bearings, not everyone has had problems with them, but the simple fact is that a problem exists. There is absolutely nothing wrong with my setup, I am on a balanced Timbo crank, and I feel my flywheel failure is only minutes away. I think Boomer and I agree after this weekend that pinning them is actually hurting their longevity, so another fix is needed. I vote for completely new units. I will order two. Tell me where to send the check. We should be able to do everything the other quad makes can do while on the air, and not have to worry about this stuff. My jumps keep getting bigger and longer everytime I go out, and soon I will need to start thinking about pitch corrections in the air. I need to know that my quad will not fail after perfoming these actions. Didn't Wistech have some flywheels made out of steel for himself?

[peterock]

Who has spun the most flywheels???

Just asking as if a new design comes out, I would think they would be a good canidate to test it.

[jwheat]

QUOTE (peterock @ Jul 6 2007, 08:18 PM) <{POST_SNAPBACK}>

Who has spun the most flywheels???

Just asking as if a new design comes out, I would think they would be a good canidate to test it.

Probably USAMoto! Brian pushes his quads to the limit.

[cannondale27]

Probably USA Moto.You are right it is enough of a issue that odds are its going to happen to everyone sooner or later.Probably when your just about to launch off a jump.Scary!Not sure best way to test them maybe get ten out there and wait a year?I could swing $300 for a prototype.

[Canniboomer]

I don't really think that the newer bolting is weakening them, but the stresses can be so severe that the bolts are actually being pushed off-angle and smashed into the softer aluminum and outwards -- if the bolts manage to stay in place, the same flywheel would have to either hold (barely), or crack instead. It's true, that the end-result is worse than a simple spin. Once cracking occurs, or the bolts are smashed out into orbit, it can get a bit ugly under the stator cover.... but it appeared to me like the failed flywheels probably lasted longer while fighting off the dreaded "spin". I have about 10 pure stock "spun" flywheels in a machine shop nearby (they are not intended for re-use yet -- those are just waiting in process as trial specimens for new "welded" faceplates -- maybe a 5th-generation fix attempt by now, I lost count).

But as an afterthought about one of the failures:....Cdsracer's stator bearing is suspect, with detectable up-down shimmy. And the stator seal has been leaking worse than most I've seen. That could explain the worsening flywheel life over time. I would suspect that any oscillating from a worn stator mainbearing is Greatly amplifying the strain on the flywheel. A flywheel spinning at 10k on a bad bearing could be the equivalent of one spinning at 20k on a good bearing,... who knows?
His motor is sweet, and has amazingly lasted for a long time, but the bearing play is likely wreaking havoc on the flywheels at an accelerating rate. And if I had used harder steel bolts on his flywheel, (instead of the stainless ones), it would likely have lasted longer and without shearing the bolts (and maybe even lasted until the NEXT trip when he would be even FARTHER away from camp!).

IdahoCannibal also had lots of trouble spinning one flywheel after another, and later pulled down the motor for another reason, and discovered a failed stator bearing. His crank was a Falicon, and he also had constant and excessive seal leakage.

Anyway, that mainbearing is likely another potential cause for the weak flywheel design to fail sooner, and we all agree on the need for a permanent fix, or a complete flywheel replacement. Some day, I'm sure our persistence will allow us to ride them like Honda's! We'll get there.