KZ900 Stripped Spark Plug Hole

I have a 1976 KZ900 that I picked up a year or so ago. When the bike is running, I would see condensation around the #1 plug and the plug would sometimes be loose. I started the bike yesterday and the #1 plug came out of the head. Now whenever a plug is put in and the bike is started, the plug becomes loose. I believe that the spark plug hole is stripped. I just put come JB weld on the spark and will check it in a couple of days to see if it will hold, if not, I guess I will have to rethread the hole. Does the head have to come off in order to fix this issue ?

I wouldn't rely on JB weld or ride it until it is properly fixed. If that plug shoots out of there while you are running at speed you may find yourself in trouble. Plugs you may end up with JB weld in the combustion chamber. Timesert (see 1st video link) is an excellent repair. You can buy the kit or have a machinist install (this is probably the most cost effective option). Some guys install them with the head on the bike; they load things up with grease to capture the debris (see second video link). Others pull the head to ensure no debris is left in combustion chamber. Ed

What was used to trap the shavings when tapping the threads ?

Please pull head!!!

BIGKEVIN wrote: What was used to trap the shavings when tapping the threads ?

I think he was relying on the shavings sticking to the grease between the flutes of the tap. Then he blew air into the cylinder which to me would just distribute any shavings around on top of the piston. I guess you could use a powerful vacuum or maybe grease on a pipe cleaner to pull out shavings from the cylinder, but I doubt you could get them all. Ed

Pulling the head would be the best way to do it so the shavings wouldn't get into the engine. How difficult is it to pull the head ? Does the engine have to come out of the frame ?

No; you can pull the head with the engine still in the frame. It will cost a few bucks because you'll need a new head gasket and probably a base gasket, but at least you won't need to worry about shavings damaging the engine. Ed

Pulling the head isnt too bad. If you havnt done it read up on installing the cams. Line them up on the proper marks so you know what you are looking for on reinstall. The motor stays in the frame.
Wayne

You can fix the head on the bike, just like 650ed posted. grease up the Tool/ tap, very little will escape. The soft Aluminum will blow out without any concern.
Ask anyone with a Ford Triton Engine, how many Spark Plug holes have been repaired and if the head was removed.
I've done hundreds over the years, especially on the old Air-cooled VW's, its quick and easy, when done correctly.
Some prefer the Helli-coils, some the inserts, either will work when installed correctly.

Pulling the head is the right way to do it.
We had times when customers didnt want to spend the money and had me poor boy it. I dont recommend the grease it can fall into the cyl with shaving in it and get stuck all in the cylinder.

The best way to poorboy it, is to turn the motor until the exhaust valve just slightly opens and visually make sure the exhaust valve wont be touched. Then get an air blow gun with a rag and put it into the exhaust pipe.
You;ll notice there is about 7-10 lbs of air blowing in reverse now and air is coming back through the spark plug hole.

As you tap slowly with NO grease, the small shavings will be coming back out the sparkplug hole and blowing past the cutouts made in your tap.
When finished, back piston down about 1 inch and blow it out again.
Knock on wood, this procedure has always worked and the bike left running.
P.S. Timeserts are superior to helicoils.

plug can be fixed on the engine without removing head. the best way is to get a shop vac put the hose on the blow side tape the hose to exhoust turn on vac then turn engine until you can feel air coming out plug hole with no plug installed then use grease on the tap and tap hole. with air and grease you will not get metal in engine. then install the timesert or heilicoil plug repair kit then install plug and your good to go.

i have done it with grease. it works fine. just put the piston at the top first.