[CAB]

Oh man, that sucks.

Sent from my VOG-L04 using Tapatalk

 

[sac67]

Is the restoration done?

 

[sac67]

Bad news ... my cylinder head / valves blew! Driving 70km/h and the engine just got stuck, shut off and refused to start. No warning or errors.

Opening the top-end. It looks like the valve lever (red) broke off with the spring stuck in the down position. Don't know if this is the cause or something else. I remember the valve clearance was a tad (~0.05mm) outside the range. This timing blew all the other valves. They were stuck in the piston.

View attachment 97111

Piston is beyond repair
View attachment 97108

Looks like I have to replace this cylinder head.
View attachment 97109

For your reference, this is how it looked before:

View attachment 97112

I still have to check the piston housing and crankshaft for play....

Any thought what could have caused this? The bike had enough oil and didn't overrev

It's so sad to see what happened after the rebuild. I hope the crankshaft was not damaged by this.
Do you think this had anything to do with no play in timing chain while you were putting it back?

 

[OneJzsupra]

Hmmmmmm, is it me or is lip of the ring land busted off of the piston in that photo? Did you measure the ring gap correctly?

 

[Siddhant020]

This happened because the Rocker Arm Broke and got stuck, or either because of faulty valve Spring.

Now you gotta change the
Intake Valve
Exhaust Valve
Valve Spring Seat
Valve Stem Seal
Inner & Outer Valve Springs
Valve Spring Retainer
Valve Collet
Rocker Arm
Cylinder Head
Cylinder Piston Block

I advise you thoroughly check the timing chain, Cam Shafts, Valve Lever Shaft and Timing Chain tensioner for any damage.

The same problem happend to me because of a faulty valve Spring, the Cylinder Head, Valves, got damaged. Got to change everything because of that.

 

[OneJzsupra]

I'm planning on do a refresh / build on my head. I was hoping to find some aftermarket valves and spring but I can't seem to find any = (

 

[seth.robbins]

What size puller did you end up using to remove the rotor?

 

[kamil290194]

Przyjacielu tu był problem z głowicą dlatego silnik wybuchł .

 

[RUNNINGMAN922]

Darn. So sad to hear this

 

[10trevorduke]

And just for fun - this was the quote (in HKD - so divide by 8 for USD) they gave me for look at the bike. Later I found out they didn't even look at the spark plugs or throttle body ... just were just looking to charge me through the roof. And this is the official KTM shop... View attachment 95594

I had the exact same problem with my crankshaft. Bought a new one put it in went to start it and still getting water in the oil. Did you have the same problem?