"POP" goes the spark plug

Well i got myself motivated enough to get my 77 kz 650 b1 back on the road, i put in 4 new spark plug's and i made sure they were tightened down enough. Road it around for a bit and all was well. So i decided to take it to work, it ran like a raped ape on the way there with no problems at all. When i was on my way home i was cruising along and decided to lay into it a bit. Then i heard a loud "POP", so i hit the kill switch and pulled over only to find my spark plug in my #3 cylinder completley blew out. I looked on the plug hole and it was completley smooth, with no threads left.................crap. So i limped it home with the #3 plug out. Im guessing i need to do a thread insert, any ideas on what size i need? Any recomendations on how to do it? Im bummed i just got it running really heathy. Here is a list of the mods on the bike, a 710cc kit, 26mm mikuni's off of a kz 1000, pod air filter's, and a 4 into 1 vance and hine's pipe, with the regular baffle fitted with the fiberglass removed, it has dyna 3ohm coils, and dyna copper core wires, im still running point's but they are brand new.

Timesert makes a product just for this. I've just their stuff to repair ruined threads in the block of my kz1000. It's quality stuff. I've purchased some kits from an Ebay store "toolsqwik" He carries a decent inventory and ships quickly.

Check out their website: www.timesert.com/html/sparkplug.html

hops this helps...

I got mine at Napa. Happened to my #3 plug also! Something with that 3rd cyl.??The kit comes with a tap & 3 inserts makesure ya use the right one. GL

Later, Boots

Number 3 cylinder here too........... Timesert fixed it

when you get the kit and your going to start doing it put your piston up to tdc on the compression stroke put lots of grease on the cutter and take your time and pull it it out from time to time to clean out the alluminium pieces also get some Q-tips for after you have made your cut and put grease on it and swab it around the top of the piston so you will pick up any cutting's that have fallen in to the cylinder just take your time and it will work out well for i've had to do it my self at the track a few times between rounds and it has always worked out well for me. good-luck it really isn't that bad of a problem.

Wow.......thanks for the replies guy's. I will take your advice timebomb,i piced up a timesert today......i already have the kit from when i stripped the plug hole on my z1 a couple years ago. Hopefully if all is well i will be riding it again this weekend............thanks

Whoa, are you accomplishing this with the head on the engine? :blink: Please say it isn't so....

if your carefull it is very do able with the head still on the engine i've had to do it myself a few times

I realize your experience over mine Tim but that would just make me way too nervous...

With my luck, I'd probably drill a hole right through my piston dome...:blink: :laugh:

I did mine with the head on and it was easy. Use lots of grease, clean the cutter and re-apply new grease until you've cut threads all the way through. Just take your time.

I lost #4 on a 900 one time but the insert was still on the plug. Previous owner must have butched it because I had to buy a new head

I put the timesert in tonight, i did like you said timebomb and it worked perfect, lots of grease on the cutter.....there were no shavings in the motor. Im going to leave it cure over night......hopefully i will fire it over tommorow and all will be well.