Spark Plug Popped Out!

Ancient Order

New Member
Feb 29, 2012
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Tucson
I was just riding along earlier today and I noticed the engine wasn't really putting out a lot of power when I turned up the throttle and all of the sudden POP! I look down and the spark plug is dangling from the connector and I have to pedal home.

This is really weird as the threads don't even seem to be stripped on the head. Should I just screw the spark plug back in and see what happens? Or am I gonna need a whole new one? And do you need to get an new gasket every time you take the top of the head off?

Thanks
 

max350

Active Member
Apr 10, 2010
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Sweden, Örnsköldsvik
I was just riding along earlier today and I noticed the engine wasn't really putting out a lot of power when I turned up the throttle and all of the sudden POP! I look down and the spark plug is dangling from the connector and I have to pedal home.

This is really weird as the threads don't even seem to be stripped on the head. Should I just screw the spark plug back in and see what happens? Or am I gonna need a whole new one? And do you need to get an new gasket every time you take the top of the head off?

Thanks
Simply screw the spark plug back in the head. You feel if the thread is broken in the head
 

wayne z

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Dec 5, 2010
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louisiana
You can re-use the headgasket only once, by flipping it over, so the slight bevel of cylinder surface can re-mash the gasket.

A lot of times the sparkplug threads are a bit shorter than the threaded hole in the head. You might put a longer threaded plug in it if the threads are damaged, but check carefuly for interference with the piston top.
 

Al.Fisherman

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Sep 9, 2009
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You might want to use Copper Spray a Gasket (Copper Kote) or aluminum paint on the head gasket. Coat each side and install. Torque to around 120-175 INCH POUNDS.


You can re-use the headgasket only once, by flipping it over, so the slight bevel of cylinder surface can re-mash the gasket.

A lot of times the sparkplug threads are a bit shorter than the threaded hole in the head. You might put a longer threaded plug in it if the threads are damaged, but check carefuly for interference with the piston top.
Generally this is the norm. I have used a head gasket more then once. But in doing so I will increase the torque on the head nuts.

I bought one of these about 30 years ago, I needed it for a job I was doing on a small block Chevy. Comes in handy when needed. It won't repair the threads, but cleans them up. I use it during all my builds as the threads may not be as clean as I want.
http://www.amazon.com/Double-Spark-Plug-Hole-Rethreader/dp/B00447YHLI

http://www.ebay.com/itm/14MM-18MM-S..._Automotive_Tools&vxp=mtr&hash=item4163131906
 
Last edited:

rustycase

Gutter Rider
May 26, 2011
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Left coast
They covered it all, but I got 2cents burning a hole in my pocket...

On a motorized bicycle, it becomes critical to do at least a quick inspection of the major components each time it is operated.
Same as an aircraft.
REALLY bad things can happen if certain details do not get attention in a timely fashion.

After a while, you will learn which items require constant attention, or periodic maintenance. Yet with a chinagirl, there will ALWAYS be surprises! lol

Good luck
rc
 

2door

Moderator
Staff member
Sep 15, 2008
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Littleton, Colorado
How tight are you torquing the spark plug? If you don't own a torque wrench, you need to buy one.

If the threads in the head look okay just put the plug back in and tighten it to about 100 inch pounds. There's no need to remove the cylinder head. You should be able to see the threads without removing it.

Tom
 

thegnu

New Member
Sep 15, 2011
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freedom pa
General rule of thumb when tightening your spark plug without a tourqe wrench seat it firmly then give it an extra 1/4 turn . works every time .
Gary
 

2door

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Staff member
Sep 15, 2008
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Littleton, Colorado
Typically on a cast iron or aluminum head I don't either but the aluminum/threads used on the HT can be questionable. I'm just being overly cautious maybe...but it can't hurt.
Tom