All right. riding last night and my quad stalled out. I wasn't on it at the time but my brother was. He was going through the gears getting on it pretty good and just like that it died out. He was probably 3/4 throttle 4th gear at the time. I also had an AFR meter hooked up to it and he said when it happened the meter indicated it suddenly when lean as it died. (but that may make sense as it probably wasn't pumping fuel anymore at that point)
So in my trouble shooting.
1. Checked all air intake boots - all secure
2. Check for fuel - pump circulating fuel just fine
3. Check for spark - good spark
4. Removed air box and throttle body - notice the bypass actuator is extremely warm ( notice just turning the key on and letting it sit for about 30 seconds the actuator es extremely warm.
5. Check the injectors are pumping fuel - I notice the first initial priming squirt but not really anything after that.
6. Install new ECU - no change
7. Check flywheel - didn't remove nut to see if it spun slightly, but no cracks or obvious signs of failure.
I didn't have spare actuator to see if that was causing the problem or not.
Quad Stalled
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dalewannbe
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- Joined: Wed Mar 10, 2021 10:41 pm
and the follow-up...................
I don't have the special tool to remove the flywheel, however removal of the nut indicates spun flywheel as the key is no longer pointing at the "C" in cannondale but at about the "D".
So I guess the shatters all the myths about breaking in the air while jumping or cranks harmonics or all the above..........Simple problem is week design that can handle the quick reving under load the engine experiences once we start modifying them.
This flywheel spun while doing straight runs down the lane between two fields.
I don't have the special tool to remove the flywheel, however removal of the nut indicates spun flywheel as the key is no longer pointing at the "C" in cannondale but at about the "D".
So I guess the shatters all the myths about breaking in the air while jumping or cranks harmonics or all the above..........Simple problem is week design that can handle the quick reving under load the engine experiences once we start modifying them.
This flywheel spun while doing straight runs down the lane between two fields.
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wayneschofield
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- Joined: Wed Mar 10, 2021 10:41 pm
If you need a flywheel puller quickly, then a 'Stihl' chainsaw shop should have them. The thread in our flywheels is M26x1.5.
Crank torsional vibration would cause exactly this kind of failure.... It's not an 'out of balance' thing, it is simply the unavoidable fact that, as piston speed increases through the cycle (mid-stroke), crank speed decreases to keep the energy balanced within the 'control volume'.... Through a rotation, the crank goes faster through top and bottom dead centres and slower through the mid strokes. This means HUGE torsional forces within the crank assembly, far more than the torque produced by the engine combustion, especially at higher revs.
A heavier crank (or, more accurately, a crank with a greater polar moment of inertia about it's rotational axis) or a lighter reciprocating assembly (piston, wrist pin, top end of rod) would reduce the acceleration rates of the crank.
Lightening the flywheel outer, and thus it's polar moment of inertia, would reduce the FORCE on the inner part of the flywheel for a given amount of ACCELERATION, meaning it would allow more revs before the stress was at the same level.
Using fewer revs would reduce the acceleration rates considerably too. I'll have to dig out the equations but, if I remember correctly, the acceleration increases with the square of the speed. So if you double the speed, the acceleration, and thus the force on the flywheel, would be four times as high.
We can't easily or inexpensively increase the inertia of the crank, or lighten the reciprocating weight but, as a quick fix, try lightening the outer periphery of the flywheel. There is some scope to get a little weight off either side of the phonic wheel, and a little off the phonic wheel itself, as the wheel is wider than the crank sensor 'tip'. You could also get a bit of weight from the alloy outer face if you start just below the 'cannondale' lettering and gradually taper outwards. I wouldn't take any from the middle because you will lose some strength.
One-piece flywheels are on the way.... It would be nice if they could be the same price as a stock one, $100, but it just can't happen I'm afraid. My engineer reckons about twice that at present. I'll post some pics when they're ready... I'll send some prototypes over there for testing before having a run of quantity done...
Crank torsional vibration would cause exactly this kind of failure.... It's not an 'out of balance' thing, it is simply the unavoidable fact that, as piston speed increases through the cycle (mid-stroke), crank speed decreases to keep the energy balanced within the 'control volume'.... Through a rotation, the crank goes faster through top and bottom dead centres and slower through the mid strokes. This means HUGE torsional forces within the crank assembly, far more than the torque produced by the engine combustion, especially at higher revs.
A heavier crank (or, more accurately, a crank with a greater polar moment of inertia about it's rotational axis) or a lighter reciprocating assembly (piston, wrist pin, top end of rod) would reduce the acceleration rates of the crank.
Lightening the flywheel outer, and thus it's polar moment of inertia, would reduce the FORCE on the inner part of the flywheel for a given amount of ACCELERATION, meaning it would allow more revs before the stress was at the same level.
Using fewer revs would reduce the acceleration rates considerably too. I'll have to dig out the equations but, if I remember correctly, the acceleration increases with the square of the speed. So if you double the speed, the acceleration, and thus the force on the flywheel, would be four times as high.
We can't easily or inexpensively increase the inertia of the crank, or lighten the reciprocating weight but, as a quick fix, try lightening the outer periphery of the flywheel. There is some scope to get a little weight off either side of the phonic wheel, and a little off the phonic wheel itself, as the wheel is wider than the crank sensor 'tip'. You could also get a bit of weight from the alloy outer face if you start just below the 'cannondale' lettering and gradually taper outwards. I wouldn't take any from the middle because you will lose some strength.
One-piece flywheels are on the way.... It would be nice if they could be the same price as a stock one, $100, but it just can't happen I'm afraid. My engineer reckons about twice that at present. I'll post some pics when they're ready... I'll send some prototypes over there for testing before having a run of quantity done...
QUOTE (peterock @ Jun 9 2007, 11:35 PM) <{POST_SNAPBACK}>
and the follow-up...................
I don't have the special tool to remove the flywheel,
I don't have the special tool to remove the flywheel,
Aren't you the local ATK dealer? C'mon, you don't have a $10 tool for the most common problem with the brand that you are selling?
You should keep one of these along with a flywheel in the toolbox of the trailer.QUOTE (peterock @ Jun 9 2007, 10:35 PM) <{POST_SNAPBACK}>
So I guess the shatters all the myths about breaking in the air while jumping or cranks harmonics or all the above..........Simple problem is week design that can handle the quick reving under load the engine experiences once we start modifying them.
What myths? You are the only one I recall saying that in the first place. Everyone has pretty much just accepted that there are way too many teeth in the design resulting in too little of meat for the teeth to bite into.
And dang Wayne, what do you do for a living? You make me want to go back to school again.
QUOTE (haydug @ Jun 11 2007, 01:09 PM) <{POST_SNAPBACK}>
Aren't you the local ATK dealer? C'mon, you don't have a $10 tool for the most common problem with the brand that you are selling? You should keep one of these along with a flywheel in the toolbox of the trailer.
You should keep one of these along with a flywheel in the toolbox of the trailer.Haydug, you crack me up.
Is that really the most common problem with these? I have a spare flywheel, but no puller. I guess I should have one, but I probably won't get one until I need it. Actually, the day I need it, the stores will be closed, so I'll get it the day after I need it. Sounds like the way I like to do things.