F3 675 / 800 Head Failure - There is hope! - Page 2 - MVAgusta.net
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post #11 of 241 (permalink) Old 12-27-2016, 02:04 PM Thread Starter
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Going to drop this link here from another thread I found this morning looking around.

I see at least one other failure on the middle cylinder

http://www.mvagusta.net/forum/showthread.php?t=57978
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post #12 of 241 (permalink) Old 12-27-2016, 03:13 PM
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To both of you that report the same failure, was it the middle cylinder?

There is a lot of investigation that needs to be done here so the more data we have to work from the better.

It would also be good to know what the riding condition was when the valve let go.
Are you street or track guys?
Were you slammin' it or was this general street riding
Did it let go on accel or decel?

Any aftermarket electronics on the bike?
Did you change anything on the bike without putting it on the dyno afterwards?

Again, the more data we can collect, the tighter the investigation becomes.

I told you all that this is real.
These guys are into major repairs to get this fixed - sorry guys.

Bernie
Mine was inlet on cylinder 1, looks like your failure with minimal piston damage valve head snapped from stem and imbeded in the port. When I finally removed the valve from the port I was surprised to find no damage to the valve seat.
The failure happend during a racing start, must of happened at around 12000rpm in first gear. I was running bazzaz unit with stock motor kicking out 124rwhp with baffle.
Also had 2no. snapped inlet valve springs, one on the failed valve.
The bike up to this year was a road and track day bike about 50/50 split with 15500 miles on the clock.

Hope this is enough info.
John
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post #13 of 241 (permalink) Old 12-27-2016, 04:05 PM Thread Starter
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Originally Posted by dudman View Post
Mine was inlet on cylinder 1, looks like your failure with minimal piston damage valve head snapped from stem and imbeded in the port. When I finally removed the valve from the port I was surprised to find no damage to the valve seat.
The failure happend during a racing start, must of happened at around 12000rpm in first gear. I was running bazzaz unit with stock motor kicking out 124rwhp with baffle.
Also had 2no. snapped inlet valve springs, one on the failed valve.
The bike up to this year was a road and track day bike about 50/50 split with 15500 miles on the clock.

Hope this is enough info.
John
Every little bit helps.
To clarify, you had 2 inlet valve springs fail at the same time?
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post #14 of 241 (permalink) Old 12-27-2016, 04:24 PM
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Quote:
Originally Posted by dudman View Post
Mine was inlet on cylinder 1, looks like your failure with minimal piston damage valve head snapped from stem and imbeded in the port. When I finally removed the valve from the port I was surprised to find no damage to the valve seat.
The failure happend during a racing start, must of happened at around 12000rpm in first gear. I was running bazzaz unit with stock motor kicking out 124rwhp with baffle.
Also had 2no. snapped inlet valve springs, one on the failed valve.
The bike up to this year was a road and track day bike about 50/50 split with 15500 miles on the clock.

Hope this is enough info.
John
Every little bit helps.
To clarify, you had 2 inlet valve springs fail at the same time?
Yes, two failed inlet valve springs discovered at the time, can't be certain they failed at the same time. But I did feel two moments of power loss down the strait the previous race weekend. Maybe connected to the spring failure maybe not. But never felt it before or since.
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post #15 of 241 (permalink) Old 12-27-2016, 05:11 PM Thread Starter
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Good to know - Thanks
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post #16 of 241 (permalink) Old 12-28-2016, 01:29 AM Thread Starter
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Interesting video if you want to see the duress a valve spring can be put under

https://www.youtube.com/watch?v=_REQ1PUM0rY
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post #17 of 241 (permalink) Old 12-28-2016, 01:58 AM
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Quote:
Originally Posted by ZAGRacing View Post
To both of you that report the same failure, was it the middle cylinder?

There is a lot of investigation that needs to be done here so the more data we have to work from the better.

It would also be good to know what the riding condition was when the valve let go.
Are you street or track guys?
Were you slammin' it or was this general street riding
Did it let go on accel or decel?

Any aftermarket electronics on the bike?
Did you change anything on the bike without putting it on the dyno afterwards?

Again, the more data we can collect, the tighter the investigation becomes.

I told you all that this is real.
These guys are into major repairs to get this fixed - sorry guys.

Bernie
Mine was the middle cylinder #2. I have a mixture of track and canyon riding with rigorous maintenance schedules; almost paranoid schedules. Failed on a street canyon riding hard. Clearances inspected 1000 miles before failure and all were well within spec. I have video on IG. Add me Patrick_kolby video posted on Aug 2nd 2016

Last edited by 71154; 12-28-2016 at 02:01 AM.
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post #18 of 241 (permalink) Old 12-28-2016, 02:12 PM Thread Starter
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Originally Posted by Pkolby View Post
Mine was the middle cylinder #2. I have a mixture of track and canyon riding with rigorous maintenance schedules; almost paranoid schedules. Failed on a street canyon riding hard. Clearances inspected 1000 miles before failure and all were well within spec. I have video on IG. Add me Patrick_kolby video posted on Aug 2nd 2016
Thanks for that!

Guys, please reach out to anyone you can that has suffered a failure in the valve train, even if they have already had the engine repaired or replaced, the data is critical for focusing in on the real problems.

So far the primary culprits are:

1) Valve spring failure
2) Valve failure at the base
3) There have been reports of the top of the valve being nipped off by the keepers but no data reported here as of yet.

One of our heads goes under the knife next week.
The other is stock and undamaged so we are going to hold off on doing anything to that one until we feel the issues have been resolved.

There will some changes made to the head right out of the gate as we are implementing some proven techniques from some really experienced engine builders. The rest we will tackle one at a time.

Stay Tuned.
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post #19 of 241 (permalink) Old 12-28-2016, 03:33 PM Thread Starter
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I would also like to add a general question for better understanding.

What is the highest temp readout you guys have all been witnessing on the dash in bars? This is for anyone who rides a F3 675 or 800, not specifically racers or track day guys.

Would like to get a handle on the heat cycles these engines see.
If you had a high temp reading on the dash or a warning at any point while riding, let us know.

And if you could provide that with the temp outside that day, it would be even more helpful. Approximately on course.
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post #20 of 241 (permalink) Old 12-28-2016, 03:34 PM
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My f3 800 had the head of the valve snap off on the middle cylinder inlet.
Race/track bike only and went on deceleration.
It destroyed the head and piston!
No warning prior to shitting itself.
Outside temp approx 25 C

Last edited by zxrjohn14; 12-28-2016 at 03:36 PM.
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