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Where's Waldo, or WTF happened here?

Axle broke, thus relieving tension on the block and allowing movement to cause the mess on the drive side. The non driven side is being held in by the safety wiring, making it appear normal.
 
Axle adjuster failure. Looks like that bolt couldn't deal with the forces.

I had something very similar happen on my Ducati ST2 six or eight years ago. In my case, the adjuster plate broke with the same results. I figured that for some reason I hadn't tightened the axle enough or something, but the adjuster plate was clearly not strong enough. Here is a picture, below, of the old one and the replacement that I got from the dealer. Somebody figured out that the old one wasn't strong enough and made it stronger. Mine only had to deal with 80 hp, though. I didn't bother getting a stronger one for the non-chain side.

ST2_EndPlates.jpg


This is what mine looked like when it was still together:
LeftAxle.jpg
 
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Isn't it obvious? Too much ugh for the amount of yut you applied.
 
Papi said:
OK Barf wizards, let's see who knows what happened here.
Hint: It's not the chain.

Before I rip this apart and shoot a bunch of pix; I'd like to see who can figure out what the issue is and why it happened. Successful and most - thought out thorough answer articulated well - will get a Mojave Magnum T-Shirt from the event we ran in. :party

You get 1 pic, that's it. Now here's what happened-

In the 4th round I was at the line attempting my 200MPH pass. In my previous pass at 199MPH, I felt my 1/2 mile speed was to slow, so I was going to load the bike up more to a drag start to gain about 10MPH at the 1/2 which should have put me at about 205 in the 1.5 mile.

I ran the motor up to 6k for a drag styled launch, leaned up over the front bars and slipped the clutch to go. At about 25' in, the bike juddered heavily like clutch chatter (new clutch with only 3 passes on it, and ran perfect before) and it began to surge the bike. I tried to power through it, thinking I was spinning the tire a bit when a huge bang came from the rear. Now remember that this Prod Bike is 240HP and 140ft.lbs of torque. The chain/sprockets were in excellent condition, well lubricated and tightened accordingly. Axle alignment before start was squared within +/- .5mm

Study the Pic, and win the Mojave Magnum Participant Shirt if you are right!
GO!
Click to expand...

Your axle dun borked
 
As other have said, the high amount of torque being applied all at once was enough to pull the axle forward. It's hard to fathom the force being applied was high enough to cause the leading edge of the axle block to push its way past the head of the adjusting screw... UNLESS, the axle nut wasn't tightened to spec and the adjustment screw was backed so far out that it flexed enough that it finally failed (bent) from the force being applied.

What's the torque spec for the axle nut? How old is the chain? (see where I'm going with this?)

Old/stretched chain> adjusting screw backed far out> axle nut not torqued to spec> high load being applied to adjusting screw at once> adjusting screw deflected (bent)> :wow:wtf
 
sfdj_tim said:
Old/stretched chain> adjusting screw backed far out> axle nut not torqued to spec> high load being applied to adjusting screw at once> adjusting screw deflected (bent)> :wow:wtf
Click to expand...
Do you seriously think someone like Papi would have an old, stretched chain on a bike he was going to go over 200 mph on? Seriously? :x
 
The obvious answer is that you didn't wheelie for safety and so this is what happens.
 
ScottRNelson said:
Axle adjuster failure. Looks like that bolt couldn't deal with the forces.

I had something very similar happen on my Ducati ST2 six or eight years ago. In my case, the adjuster plate broke with the same results. I figured that for some reason I hadn't tightened the axle enough or something, but the adjuster plate was clearly not strong enough. Here is a picture, below, of the old one and the replacement that I got from the dealer. Somebody figured out that the old one wasn't strong enough and made it stronger. Mine only had to deal with 80 hp, though. I didn't bother getting a stronger one for the non-chain side........
Click to expand...
Wow. Well those pictures don't inspire me to buy I-tal-i-an. That looks like way too light weight for it's intended job.

This thread should have had a poll. Then we could have all checked "incompetent mechanic" or "yo' mama".
 
ScottRNelson said:
Do you seriously think someone like Papi would have an old, stretched chain on a bike he was going to go over 200 mph on? Seriously? :x
Click to expand...

Easy there, Mr Nelson... wasn't trying to dump on Papi and get you riled up. :cool

So maybe the chain isn't old but if you look at the pic of the other side of the bike, you can see that the axle block is pulled back pretty far... or should I say, far back enough that the adjustment screw is backed out a ways. Obviously, there's a reason that the adjustment screw is bent. My thinking is that a +1" long screw is much easier to deflect than 1/2" long screw. There's a LOT of load being applied, all at once, and somethings gotta give.
 
axle nut torque def doesnt provide enough friction to keep the axle from moving around all by itself. ive had an axle move on my 600s if i dont snug the adjuster up against the axle after torquing the nut properly. over 3x the torque would def do some crazy things. the axle nut torque is mostly there to keep the swingarm square.

+1 to buckled the adjuster bolt
 
I'm with the "axle broke" or "rear wheel bearings or spacer disintegrated" crowd.... something would have to release the tension on the adjuster (which holds it in place) for it to move like that
 
Rob said:
Isn't it obvious? Too much ugh for the amount of yut you applied.
Click to expand...

omg... :rofl :rofl

You win the interntez today!! :teeth


Knowing Papi, none of the equipment would be "old", or not torqued to spec.

I'm not mechanically adept enough to figure it out. But I'm voting with Corndog, because he's been machining stuff like this for decades.
 
planegray said:
I'm with the "axle broke" or "rear wheel bearings or spacer disintegrated" crowd.... something would have to release the tension on the adjuster (which holds it in place) for it to move like that
Click to expand...

I think the bearing and spacers answers are creative.

Yet, that axle is fine. The forces exerted on it in the orthogonal direction (up and down) are far greater than the pull of the chain (even Papi's enormous pull).
 
OK here goes, first I can't tell what the safety wire is for but it looks like the aluminum has failed from the load applied to it then as the axle was pulled forward encountering the adjuster the rounded shoulder of the axle just pushed the adjuster (bolt ) aside.
What is the safety wire for?
 
The more I think about it, the more I like the bearing or spacer answer. The axle clearly moved; I think that damaged the adjuster block, not the other way around. Based on the pic, it doesn't look like the alignment block failed and was pushed onto the stop nut. It looks like a strong sideways torsion pulled it past the stop nut. If the swingarm stayed aligned, that shouldn't happen. But as others have said, the axle is what keeps the swingarm aligned. And the axle nut is still there, the axle didn't back out. But rotating the axle forward on the left would effectively shorten it; now there's enough play, and enough force, to pull the adjuster past the stop nut, bending the nut out (because it's definitely bent).

I wish Papi would just come back and tell us. Forget Waldo, where's Papi. Also, we should do this more often.
 
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El Feo said:
I think the bearing and spacers answers are creative.

Yet, that axle is fine. The forces exerted on it in the orthogonal direction (up and down) are far greater than the pull of the chain (even Papi's enormous pull).
Click to expand...

peak force is far greater for sure. a speed bump probably spikes the force >10000lbs. but i wonder how close the sustained forces are. the suspension prob bottoms at 2500lbs. 1st gear w/ that much torque, i bet u could get 2500lbs of tension into the chain. of course, the tire would have to be locked to the ground to transmit all that to the axle.
 
The axle bolt failed, the shuddering rear was the wheel on the chain side being repeatedly pulled forward and then springing back, essentially pivoting on the adjuster on the other side. During one of those cycles the chain jumped the sprocket.

Edit: I see bcv west just said that. I'm out.
 
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If you look at the surface area of where the wheel spacers clamp, up against the inside of the swingarm, most of the ones I've seen were in the neighborhood of 3/16 wall thickness, by about a 2 inch outer diameter. Some were closer to 1/4 wall thickness. But, when clamped all together with the axle nut, not a lot of surface area is being clamped. With all the torque that sled is putting into the chain, trying to pull the top of the sprocket forward, I'm sure the chain adjuster screw sees a lot of force against it. And that the adjuster bolt is part of the combination the keeps the wheel in place, not just the axle torque. If that screw is hanging out quite a ways, it definitely will bend easier than if it was all shortened up.

Just a guess, I'm no engineer, just spun a lot of wrenches and made a lot of parts (those tractors definitely will wear shit out if it isn't really stoutly made).
 
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