Completely stripped spark plug

[AK47KID]

So I was tuning the carb on my 78 atc 70 and I took the plug out cuz it was fouled and pitch black and brushed it clean with a copper grinder brush. (no I didn't use an actual grinder wheel just the brush). So I go to put it back in the engine and get it finger tight. (Or so I thought) and start tightening it with the socket wrench and I noticed it got a little tight then got loose. I keep trying to tighten it and get it tight enough. There are metal shavings there heofre I started fixing it up but didn't think anything about it being stripped...stupid me. And I yank on the pull starter and the freaking plug literally "pops" out. What do I do now? Is there any kind of sleave I can put in it? Should I just get a new head for it? Should I have the shop tapp new threads for a little bigger plug? I'm stumped and bumbed out cuz I was getting 2 of these ready for Xmas and now I have one for my brothers to share till I get this problem fixed.

[atcmatt]

Just Heli-coil it. Will have to pull the head though to do it properly.

[John Tice]

A simple Heli coil will repair the plug threads. Call around to cycle & mower repair shops, you should find a place in your area who can do this repair for you. I’ll do it for $20.00 if you send it to me.

John Tice
503-593-2908 Alternate 541-508-3944
www.smallenginemachineworks.com & www.nwsleeve.com
Turning Custom Cylinder Sleeves Since 1971

[atc300r]

I bought a metric helicoil kit at an autoparts store and it has two spark plug sleeves in it .225260

[AK47KID]

I really have to pull the head off to helicoil it? Never taken a head off before.

[briano]

You don't have to take the head off. Get the proper size helicoil kit, make sure the piston is down and then drill and tap the hole out and put the helicoil in. When you're done blow the cylinder out with compressed air to get the chips out. I've done a bunch this way and have had no problems. With the 70, I believe you need to trim a couple coils off the helicoil because they are too long. The hard part is breaking the insert tab off the helicoil once it is in the head, make sure you have a magnet that fits in the plug hole to help get that out if you drop it.

[Scootertrash]

Put grease in the flutes (grooves) of the drill and the tap. The chips stick to the grease and don't fall into the cylinder.

[DohcBikes]

Did an insert kit on an assembled engine just 2 days ago.

You WILL get aluminum in your cylinder, even if you grease the tap. Grease it heavily. Clean the cylinder after tapping.

The ideal engine position to avoid damage while tapping is to have the piston as low in the stroke as possible without having the valves open. You dont want to nick a valve or have a piece of aluminum get stuck between the valve and the seat.

Do not use a heli-coil. They are prone to breakage and they pull out quite often. They are made of a single piece of wound wire. There are much better inserts available.

Use a NAPA insert kit or a time-sert.