KTM 520 exc piston

[Beemkeemoh]

Hi sorry my bad english but i hope you guys undestand me.

Can i use this piston? Valve hitted piston and bent. Its 10-15 hours old

 

 

Edited September 26, 2018 by Beemkeemoh

[InRoostWeTrust]

You might want to post your pictures and questions on the www.ktmtalk.com site.
They have several very knowledgable engine builders commonly watching/posting and they commonly provide excellent feedback. Thumpertalk is a good site, but not filled with professionals to really help.

Looks to me that your piston is usable BUT the crank/crank bearings/connecting rod maybe damaged (need to be checked) due to the collision with the head/valves.

Best of luck!

[SnowMule]

Obviously, you need at least one new valve and head work.  Personally, I'd do all four since you've got things apart and to a machine shop.

The damage to the piston is done, don't run that piston any more.  It's going to fail sooner rather than later.  Again, engine's apart already, might as well put a new piston in there and know it's good.

Figure out why the timing jumped, and fix that before you put anything back together.

[Beemkeemoh]

2 hours ago, SnowMule said:

Obviously, you need at least one new valve and head work.  Personally, I'd do all four since you've got things apart and to a machine shop.

The damage to the piston is done, don't run that piston any more.  It's going to fail sooner rather than later.  Again, engine's apart already, might as well put a new piston in there and know it's good.

Figure out why the timing jumped, and fix that before you put anything back together.

Timing looked ok. Other valve didnt broke but valvespringholder broke. I drived high speed at road (150km/h) after 5 minutes after that this happened. Could that cause this failure?

[GOTWHEELS]

Valve stuck open. He sure to check lower cam chain sprocket key.

I had the same thing happen if It it all back together, and had power sprocket move out of time

and crash again.

[Beemkeemoh]

9 hours ago, GOTWHEELS said:

Valve stuck open. He sure to check lower cam chain sprocket key.

I had the same thing happen if It it all back together, and had power sprocket move out of time

and crash again.

Do you mean woodruf key?

Edited September 29, 2018 by Beemkeemoh

[Beemkeemoh]

14 hours ago, GOTWHEELS said:

 

Edited September 29, 2018 by Beemkeemoh

[Beemkeemoh]

which parts should I change to prevent the timing from jumping? Im scared to run the engine when its ready i have replaced:

all changeble parts to head and experts assembled the head, piston, connectionrod, timingchain, all bearings etc money spended over 1300 euros

[GOTWHEELS]

18 hours ago, Beemkeemoh said:

Do you mean woodruf key?

Yes