Spark plug sleeve

New to the forum. I did a search already, but may not have used the right terms. To make a long story short, I have a 78 KZ650B, nearly rideable, and a 78 KZ650SR parts bike. Been trying to get the B running well enough to ride, but it dies when it warms up. I found the problem this morning... Bad head gasket seal making vacuum leaks at #'s 2 and 4. I know the head has to come off, but I'm worried it may be warped. So... I started pulling plugs on the SR (which I'm told was running just a couple months ago) to try to get an idea of the condition of the head. When I pulled the #3 plug, the steel sleeve (liner?) came with it.

My questions are... What is the best way to get the sleeve off the plug without damaging the threads? And what is the best way to go about reinstalling the sleeve so that it won't come out with the plug anymore?

Sounds like someone installed threaded spark plug inserts into the head. Kawasaki didn't build the head that way. If the insert came out with the spark plug you will have to try something like red loctite to see if you can anchor them in better. Better yet is take the head to a machine shop and see if they can install Timeserts. They are a solid threaded insert but they mechanically lock into the hole and don't come out when removing the spark plugs.

It sounds like a helicoil from a previous repair came out. Nessism is correct; have a machinist install a Timesert. Ed

Thank you Nessism. It almost sounds like I may have the Timeserts in the head already. The one that came out with the plug was a steel threaded sleeve, not a Helicoil style. The outer threads had something like a saw pattern cut into the ridges of the upper threads.

I also pulled another plug and touched the inside of the plug hole with a magnetic pickup tool. It was definitely steel.

Gearboxx70 wrote: Thank you Nessism. It almost sounds like I may have the Timeserts in the head already. The one that came out with the plug was a steel threaded sleeve, not a Helicoil style. The outer threads had something like a saw pattern cut into the ridges of the upper threads.

I also pulled another plug and touched the inside of the plug hole with a magnetic pickup tool. It was definitely steel.

Not all spark plug inserts are created equal. Timeserts are the best. Auto parts stores sell less quality (also cheaper) solid inserts as well. I'd try the red loctite and see what happens. Degrease the insert and plug hole really well, let dry, then slather on the loctite and screw it in.

Thanks for the good info, Nessism! The head is on my parts bike, so I'll probably yank it off for machining. I have to do at least the head gasket on the rider, because of the vacuum leaks at 2 and 4 anyway. Might as well leave the insert out so I can hand it to the machinist with the request that he fix all of them all.

Are you sure the leak is at the head gasket? The rubber carb holders become hard with age and are a common source of vacuum leaks in the intake. They're a lot easier and cheaper to replace than a head gasket. A leak down test might be in order before pulling the head.