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Discussion Starter #22
Gentlemen, removed the valve cover and found the cause.

Both bolts that secure the intake gear to the camshaft are broken. So the intake camshaft got loose and was not rotating. Valves that stoped open probably got hit by pistons and that’s explain the broken valve guide pieces.

See on the picture the intake camshaft with the holes where the bolts were supposed to be.




The broken pieces were inside the head and was able to retrieve




Not sure why and how that would happen.

Removed camshafts already. Tomorrow will remove the head to see what damage I have on valves and see how pistons and cilinders are.


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Wow! When I removed my Cams I sorta checked those bolts and they were super tight. I used them to rotate the cams at one point! Somebody at MV Agusta must have had a Date!
 

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Discussion Starter #24 (Edited)
I really don’t know why they would break like that (camshaft, lobes and everything looks good apart from that), but assume that overtight may be one plausible cause.


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Welcome to the club! I'm in the middle of repairing the exact same problem with my 2007 F4R. Same intake cam sprocket bolts broke/came loose causing 8 bent valves and a damaged cam lobe. Fortunately, my cracked valve guides did not fall apart and get into the combustion chamber. I sent my head to Bruce Meyers in New Hampshire to have his custom-made guides installed and the seats trued. Camshaft is with MegaCycle in California to have the damaged lobe repaired. The lobe damage was caused by the broken bolt head dropping into the valve spring pocket adjacent to the sprocket where the lobe beat it to death until it finally got jammed and snapped the timing chain. I found that the bolt remnants easily unscrewed by hand indicating there was no thread locker on them from the factory! The exhaust cam sprocket bolts were fitted with thread locker and needed some muscle to remove all the way.

If you need new cam sprocket bolts, let me know and I'll mail some to you. Good, American made 12.9 socket screws (I had to buy a box of 100). Happy to share them.

Sorry to hear that MV is still not assembling engines properly. You have my sympathies.

Eric

https://flic.kr/p/2j1PM7p https://flic.kr/p/2j1SqFr https://flic.kr/p/2j1U1SS https://flic.kr/p/2j1SqGi https://flic.kr/p/2j1U1X1
 

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Thats like Horror pictures .. :oops:o_O:cry:
 

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I found that the bolt remnants easily unscrewed by hand indicating there was no thread locker on them from the factory!
With that type of washer (Wedge Lock) I would not normally use thread lock. One thing you have to do is assemble the washers in the correct orientation (big tooth to big tooth, small teeth to bolt head and substrate).
 

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The factory engine manual specifies "Strong Thread Locker" on the cam sprocket bolts, even with the Nordlock washers. And yes, the washers were assembled correctly by the factory (the other intake cam sprocket bolt head was still attached by about 1 thread and broke off as soon as I touched it with a socket). I'm reassembling the cams using red Loctite to make sure those suckers never come loose again.

Eric
 

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belt and braces, do you think that the bolts failed, just came loose due to temp / vibration or a factory mistake on the threadlok?
 

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I'm not sure if it was the lack of thread locker (remember, the exhaust cam sprocket bolts were fine: still tight and with thread locker on them) or a problem with the bolts themselves. The one intake cam bolt that was still in place had broken in two places and the head popped right off when I hit it with a socket. I wish MV had designed these sprockets so they locked into the cam somehow instead of relying on just 2 little 6mm screws to hold the sprockets to the cams. Lot of stress on these bolts.

Eric
 

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Discussion Starter #32
I have 3 brand new F4 1000 cc pistons in the original boxes with wrist pins and ring set if helps.
Not big money.
let me know if you want the part number.
[email protected]
joe
Great, thanks a lot. Will probably remove the head today and will post pics of pistons and cylinders here so you can help me determine if it’s needed.


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Discussion Starter #33
Welcome to the club! I'm in the middle of repairing the exact same problem with my 2007 F4R. Same intake cam sprocket bolts broke/came loose causing 8 bent valves and a damaged cam lobe. (...)

If you need new cam sprocket bolts, let me know and I'll mail some to you. Good, American made 12.9 socket screws (I had to buy a box of 100). Happy to share them.

(...)
Ericfreeman, sorry to hear about yours.

I just noticed that the chain tensioner was stuck half way... not sure if this would cause any problem also.

And yes, one of the bolts broke in two places for me also. Think I was luck that no pieces caused more damage.

Did not removed the head yet, but it looks like 2 valves and I’m hopping for little to no damage on pistons.

Not sure if will be able to repair my head. Already found one used that seems to be in good condition. Leaning towards replacing and then I see what to do if this one.

Will probably want some bolts. The problem would be to deal with all the shipping and customs for a pair of bolts.


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Discussion Starter #34
Guys, here is where I need most your expert opinions.

Got the head off. There is a mark on the carbon building of piston four but can’t feel by touch. Can slight feel on fingernails.





Cylinder wall looking good form me:





What you think?


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You have escaped major damage....that piston will be fine. Leave the cylinder alone.
 

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Discussion Starter #36
You have escaped major damage....that piston will be fine. Leave the cylinder alone.
Great!!!

Now the valves are bent and guides broken.

As I said, found one complete head that is looking to be in good condition. But the intake valves has the “del west” sign.

Do you know if some engine came original from factory with “del west” valves? Wondering if the head was refurbished and the seller is hiding the fact


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I contacted Del West to inquire about replacement valves for my F4 and they said they have an exclusive contract to provide MV Agusta with valves and could not sell directly to me. So, sounds like MV is using Del West valves. Be aware that they say you can't grind the valves to seat them as it will affect the oxide coating. I found that my exhaust valves have titanium heads while the intakes are steel. Regardless, I'm not lapping any of them, just cleaning off any carbon.

Eric
 

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Discussion Starter #38
Did a little cleaning on my valves and it does look like there is their logo very faded.

And look how the valves of cylinder 4 are. One of the intake went bellow the exhaust valve:






Well, should I just get this replacement complete head, new chain tensioner and rebuild?

Also, think I might have damaged a little bit the head nuts and would replace for new ones, so should order all gaskets together.


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How much for the replacement head? Be aware that it will take a specialist shop to replace the valve guides since the head needs to be heated to remove and replace the guides. I don't know who you could use in your area. You should also check the rest of your valves as some might be slightly bent. I found a pair of exhaust valves in my head were very slightly bent and you could only notice it by chucking them in a drill and spinning them. They looked perfect until I spun them and could see a little wobble of the valve head.

Eric
 

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Discussion Starter #40
Eric, it’s announced by R$ 6.800 . The guy says it came from an engine that had malfunctioned on the crankshaft and piston rod with less than 1000km. Not sure if I’m allowed to post the link here.
 
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