Piston kissed the sparkplug

Quigleyje
Topic Author
Offline
User
Registered
Posts: 65
Thanks: 5

Piston kissed the sparkplug

27 Jun 2020 05:00

I was out riding zx550 yesterday missed second bike revved and the piston hit the spark plug. Is this a rebuild now? Can I put a new plug in and ride it?

81/84 kz/zx550

Please Log in or Create an account to join the conversation.

Nessism
Offline
Sustaining Member
Registered
Posts: 7755
Thanks: 3142

Re: Piston kissed the sparkplug

27 Jun 2020 05:14

#829072

You got nothing to loose in trying. Very strange for that to happen though. Either the rod stretched or you have bearing wear/damage. It's far more common for the valves to hit the pistons resulting in them being bent in that situation.

Ed
Carb O-ring Kits : www.kzrider.com/forum/3-carburetor/61807...-o-ring-kits?start=0

www.kzrider.com/forum/faq-wiki/618026-new-owner-things-to-know

1981 KZ750E2
www.kzrider.com/forum/11-projects/604901...z750e-project-thread

The following user(s) said Thank You: Quigleyje

Please Log in or Create an account to join the conversation.

Quigleyje
Topic Author
Offline
User
Registered
Posts: 65
Thanks: 5

Re: Piston kissed the sparkplug

27 Jun 2020 05:20

#829074

Maybe it was a valve not sure just know the plug is flat. Maybe it's just time for a rebuild.

81/84 kz/zx550

Please Log in or Create an account to join the conversation.

bluej58
Offline
Sustaining Member
Registered
The chrome don't get you home
Posts: 2481
Thanks: 511

Re: Piston kissed the sparkplug

27 Jun 2020 06:29

#829076

Are they stock plugs?

78 KZ1000 A2A

Please Log in or Create an account to join the conversation.

Quigleyje
Topic Author
Offline
User
Registered
Posts: 65
Thanks: 5

Re: Piston kissed the sparkplug

27 Jun 2020 06:51

#829077

Yeah they are the stock plugs

81/84 kz/zx550

Please Log in or Create an account to join the conversation.

ckahleer
Offline
User
Registered
Posts: 476
Thanks: 162

Re: Piston kissed the sparkplug

27 Jun 2020 07:28

#829082

It's hard to believe bearings could be that bad and not making an awful knock. Check compression. Look through the plug hole at the piston half way up. Can you see damage? Turn engine a little CW then CCW. Is there slop in piston movement.If not,put in a new plug and and rev it again.

1997 ZL600
94 KE100
82 KZ305
74 TC185

The following user(s) said Thank You: Quigleyje

Please Log in or Create an account to join the conversation.

Quigleyje
Topic Author
Offline
User
Registered
Posts: 65
Thanks: 5

Re: Piston kissed the sparkplug

27 Jun 2020 07:38

#829083

Yeah there was no noise at all always ran smooth. But it revved past redline. I accelerated pretty hard before missing second. I imagine something is damaged the plug was hit hard.

81/84 kz/zx550

Please Log in or Create an account to join the conversation.

650ed
Offline
User
Registered
Posts: 15339
Thanks: 2833

Re: Piston kissed the sparkplug

27 Jun 2020 07:42

#829084

Did the spark plug have the washer on it? Ed

1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)

Please Log in or Create an account to join the conversation.

Quigleyje
Topic Author
Offline
User
Registered
Posts: 65
Thanks: 5

Re: Piston kissed the sparkplug

27 Jun 2020 07:45

#829085

Yes the washer was on. Maybe over tightened not sure.

81/84 kz/zx550

Please Log in or Create an account to join the conversation.

Quigleyje
Topic Author
Offline
User
Registered
Posts: 65
Thanks: 5

Re: Piston kissed the sparkplug

27 Jun 2020 08:31

#829089

So I looked in all cylinders #4 is the only one with damaged spark plug. The valve I can see seems to have no damage. No metal picked up with a magnet. Put new plug and I'm getting backfire through that carb. I can only guess bent valve. It still revs fine and no noticable noise.( But it was only for a couple seconds).

81/84 kz/zx550

Please Log in or Create an account to join the conversation.