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so...friday out with my father in law and a good friend...we are out riding the back roads here in sapulpa,ok
choppers running good, lots and lots of power and throttle response was unusually crisp...so we get to about a mile from the house and hit the highway on the way back to the house....i am out in front and decide to run it out....first gear...no problem, second gear...no problem, third gear...no problem.....fourth gear....pop pop sputter....dead......coasting to side of road...

tried to crank...sounds like its fouled plugs...popping and sputtering

get home pull the plugs...beautiful color..no white or dark black just not what i expected...

next step pull the nose cone....OH CRAP LOOK AT THIS





tor%20failure/IMG_20111113_172452.jpg[/IMG]


 

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Advance spring (or the pivot on the weight) gave out, then the weights hit the cam cover and sheered the bolt.

Looks like you already got the bolt out of the cam, so why do you need to pull the cam cover? Seems like you can just put a new advance unit in (might as well, and get a quality one like the Rivera unit), and a new bolt and be done with it.
 

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Scott McKelvey said:
Advance spring (or the pivot on the weight) gave out, then the weights hit the cam cover and sheered the bolt.
Sorry to disagree with you in public, but I think the springs have nothing to do with it. They only control the rate of travel and rpm point.

The pegs on the base and the holes in the weights are the stops that control how far outward the weights travel.

These get wallered out over time allowing the weights to travel too far and bind the cavity.

Some aftermarket timing covers also have slightly small weight cavities too.

Nothing a little preemptive grinding can't fix.

Respectfully,
Jason
 

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This happened on my '74 XLH Sportster...of course it was out in the country miles from anywhere. Got it home in the back of a truck. Extracted the broken bolt, put a new one in, timed it and was back on the road in a few days. Good to go. They were all stock H-D components. That was back in '88 and I don't remember replacing the AA unit and I only recall the damage as being the broken bolt. I was cruising along with a couple of buddies when it sounded like a shotgun being fired and I lost power immediately. Coasted to the side of the road and that was that.
 

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agreed, if the his weights couldn't move far enough to hit when it was new, then only wear on the advance unit would cause that (not a broken spring), which is why I said "or the pivot on the weight".

However, I've held more than one brand new aftermarket advance unit in my hand where the weights could hit the cam cover or circuit breaker housing if you spread them manually (this may have been compounded by the aftermarket housing). The unit would work fine b/c the springs provided enough tension (at least street riding) to keep the weights from hitting. But once spring(s) began to lose tension or break, then ......FAIL.

Regardless, everyone is saying the same thing: buy a quality unit, make sure it can't hit the cam cover, and keep it lubed.

Sorry to disagree with you in public, but I think the springs have nothing to do with it. They only control the rate of travel and rpm point.

The pegs on the base and the holes in the weights are the stops that control how far outward the weights travel.

These get wallered out over time allowing the weights to travel too far and bind the cavity.

Some aftermarket timing covers also have slightly small weight cavities too.

Nothing a little preemptive grinding can't fix.

Respectfully,
Jason
 

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Look at photo three. You can see the worn out pin hole in the one weight. I would say that, that is what caused it. Like every one is saying. Buy the good unit. Some even have a bearing on them. Last cheap one I had, hit the cam cover, out of the box. Cheap is cheap. Quality, gets you home.
 
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