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Discussion Starter · #1 ·
Over a month ago, I had a no start issued because the cam timing had jumped on the exhaust side on the vertical cylinder. This led to bent valves. I replaced the valves, belts, and adjusted all the valves. To my delight, the bike started yesterday and idled well. I started it again this morning with the same result. I let it idle for a few minutes and again, it performed flawlessly.

I decided to ride it this morning, and I only made it about half a mile before it shut off and would not start. After pushing it home, I took the belt covers off to again find that the timing on the exhaust side of the vertical cylinder is off. Im hoping I dont have bent valves again, but either way, this is an issue that I must resolve.

I thought that it could be the tensioner pulley, but I used a new nut and washer. Perhaps it is the idler pulley? Any help would be most appreciated. I didnt have time to do any further investigation.
 

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Does the idler pulley have any play? If not then not likely. Also If the tensioner pulley wasnt loose it isnt likely to be that. On the testastretta my guess would be most likely would be the cam pulley slipping, in which case you should be able to tell from the pully because the bolts would leave a mark where it slipped. If that didnt appear to be the case pull the pulley off and check the key way. Dont have any first hand experience on these to draw from but my understanding and looking at the parts blowout it would have to be one or the other. Less likely but possible would be the belt jumping from not being tensioned properly. Given this has happened twice that would be the last thing I would suspect.

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I got nothing to offer that would help other than my sympathies. I hope you get it sorted and are back on the road/track soon, bro. Best of luck.
 

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Discussion Starter · #4 ·
Thanks Chris for your suggestions and 998MDG for your sympathies. Once I figure this out, it should be good to go.

As for your suggestions Chris, I will check the idler pulley for play. I checked it previously and it seemed fine. I was meticulous about the belt tension on the belts and I turned the rear tire no less than 20 times before starting to make sure the tension was ok. Perhaps you are correct about the cam itself. I visually inspected it as well, but perhaps it is more difficult to detect.

One last detail: when I pulled the cover the belt had slipped off of the exhaust cam. I dont know if this helps clarify anything, but I thought I would mention it in case.
 

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Well I hate to be the bearer of bad news but if the valves hit the piston it would likely throw the belt off. :( The contact would have stopped the cam rotation but the engine would have kept going. So the belt would skip off the pulley since it was still trying to move with the motor.

At this point I would tear it all down and determine what caused it. Then rebuild all of it. Exhaust, intake, horizontal, vertical, I wouldnt chance another catastrophic failure.
 

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Discussion Starter · #6 ·
That makes sense.

I rebuilt the vertical cylinder with new valves and shims to put the clearances in spec. Ideally, it would be wise to rebuild the horizontal cylinder as you suggest. But doesnt it seem like the problem is with the vertical cylinder and more specifically the cam pulley? After replacing and adjusting valves, the same problem occurs on the same cam. Im not arguing with you; I am simply trying to narrow down the problem area.
 

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Horizontal cylinder wouldnt have anything to do with it, but if the pulley slipped and caused the damage why did it slip? Was the same thing done to the horizontal cylinder at some point? My logic would be if the key way on the cam isnt the problem why was it loose and who loosened it and why? Given those unanswered questions I would do it all, just because the why is unknown. Call it preventive maintenance.
 

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Discussion Starter · #10 ·
So for the last couple of hours I've been researching and carefully inspecting the exhaust cam but to no avail. The only curious thing about the exhaust cam is there looks to be metal shavings in the holes toward the end of the cam, but I dont have a clue what this could be. Still, I can't help but think the cam is the problem. i would think that if the idler or tensioner pulley were the problem then i would have issues with both the exhaust and intake valves on the vertical cylinder. I would also assume that the problem would be something that affected both exhaust valves since both were bent last time. By the process of elimination, this only leaves the exhaust cam itself, correct?
 

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Cam could be bent, if so the pulley would be wobbling and could have thrown the belt. Even if it were only slightly bent enough to not be visible by the eye. I would get a dial indicator and check the cam and the pulley to see if they are out of round. Or you could surmise, likely correctly that it is and replace it. I would replace all of it though, cam and pulley assembly. And probably the bearings.
 

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Discussion Starter · #14 ·
Did you swing the tensioner the correct way, as to avoid the teeth on the belt touching each other?
Thanks for the suggestion and I thought about that. Im almost positive I swung it the correct way. If I didn't, wouldn't the teeth have touched each other when I was turning the rear wheel on the stand before starting the bike? Perhaps not.
 

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Discussion Starter · #15 ·
Did you swing the tensioner the correct way, as to avoid the teeth on the belt touching each other?
Ive attached a picture of the belt and it is mangled badly and it is like that all the way around. It looks to me like the belts were touching each other. The old vertical belt looked worn, but not like this at all. Keep in mind this is a new belt. I have two questions: 1. If the cam pulley failed or if the cam is slightly bent, would it cause the entire belt to shred like this? I doubt it. 2. Is it possible that the tensioner moved slightly? I doubt it as I set it to spec. I am perfectly willing to admit if I made a mistake and swung the tensioner the wrong way. I just want to understand what happened, repair it, and get it back on the road.
 

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I've not worked on a Testastretta before, so take this with a grain of salt, but when I first got my R years ago the original owner had just had the 2nd 3,000 mile service interval done at his local Ducati dealer. Part of that service was replacement of the belts. I had ridden it all spring and summer prior to the start of my rebuild that winter, thankfully without issue... I say thankfully because when I tore the bike down I was surprised to find that the tensioner on the vertical cylinder had been rotated in the opposite direction, and the belt teeth were separated by only a few mm at the OD of the tensioner/idler pully:
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While I am not discounting the possibility of your exhaust cam being out of spec with regards to TIR, if you can see evidence on what's left of the belt that the teeth were striking each other there is little chance that anything other than the tensioner is to blame.

This is no indictment with regards to your wrenching skills, as mine was reassembled incorrectly by a certified Ducati technician at the dealership. Shit happens... be thankful that you avoided serious damage and take every precaution to ensure that it does not happen again.
 

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Discussion Starter · #18 ·
Thanks Prophet. I mentioned pictures in a previous post but forgot to upload them. In the first picture, the vertical belt does not seem to be close between the idler and tensioner pulley. However, in the second picture, it looks like they were definitely making contact. Please correct me if I am wrong.

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Discussion Starter · #19 ·
Any evidence of the cam tightening, seizing in the bearing journals? Discoloration,Streaks on the bearing surfaces? Oil restriction?
Thanks for your reply.

I looked at the bearing surfaces and there was some discoloration. I will look again when I get home and I can take pictures so you guys can have a look as well.

How could I check if there is oil restriction?
 

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Looking at the parts diagram I dont think there is really a way to tell other than looking for discoloration on the journals. By the looks of it there is no way to manually operate the pump and check for oil flow, which is what I have done in other instances. You can remove the oil sensor and put a gauge on it but that only tells you the oil pump is working, not if you have a restriction.

Belts looks close but not that close, even when they are correct there isnt much space between. And given the wear pattern on the belt I dont think that was it as only a very narrow section is damaged. If the belts were rubbing each other would think you would see the contact all the way across the rib. That looks like something was cutting into it. It still could be I suppose, but wouldnt be my first guess.

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