Spark plug not seating

[oldgsfan]

What problems will I cause my bike by running it when one of the spark plugs aren't all the way in?

I searched but didn't see this problem coming up for others. I have a 1980 GS850. I was switching out the plugs today, changing the oil. Just routine stuff. Anyway, I noticed that my no. 3 plug isn't seated all the way in.

I think it may have been this way for a while and I just now noticed it.

I tightened it as far as it will go, but even though it's snug, I can feel it's not all the way in.

It started right up and seems to run fine but, naturally, I'd feel better if the plug were in all the way like the other three.

I'm guessing the threads in the head have gotten messed up.

The only time I've retapped a head for a spark plug socked was on a VW bus years ago and in that case the spark plug kept falling out. That's not happening to my bike. The plug is in very snug, it's just not all the way in.

So, helicoil now? Or am I OK to save that for another weekend?

[7981GS]

Re-tap the hole.

The plug will do two things if it is not seated,
blow out exhaust and spark just short of the combustion chamber.

Eric

[oldgsfan]

Thanks - I was doing more reading and the insert repairs seems easy enough that I might as well do it now.

On my way to the store now for a spark plug repair kit.

[Johno]

Try a chaser

You may not need an insert just a chaser to clean up the thread.

http://www.tridon.com.au/Products/Product.aspx?SG=5&S=17&G=599&P=64356

I have used a chaser on my bike with great success when I thought I had stripped the thread.

[oldgsfan]

Ahhh...too late. I used an insert that came with a spark plug socket repair kit.

So, now I have another question for others who have done this. I couldn't reach in far enough to screw the insert in without using the spark plug.

I got it all the way in but when I tried to remove the plug, it pulled the insert out with it. So, I just put the whole damn thing in again.

It's seated now, that's for damn sure.

So I'm thinking I'm just gonna leave the plug in like it is with the insert but I'm wondering if I should try to remove the plug? Or at this point does it matter?

Oh, and someone else posted about using a shop vac, some duct tape, and tubing to clean up the shavings..that worked great!

[TheCafeKid]

Ahhh...too late. I used an insert that came with a spark plug socket repair kit.

So, now I have another question for others who have done this. I couldn't reach in far enough to screw the insert in without using the spark plug.

I got it all the way in but when I tried to remove the plug, it pulled the insert out with it. So, I just put the whole damn thing in again.

It's seated now, that's for damn sure.

So I'm thinking I'm just gonna leave the plug in like it is with the insert but I'm wondering if I should try to remove the plug? Or at this point does it matter?

Oh, and someone else posted about using a shop vac, some duct tape, and tubing to clean up the shavings..that worked great!

So are these helicoils or "time-sert" type inserts? I've found that unless you pull the head to do a helicoil, it's likely going to fail miserably if you need to pull the plug again. The time serts are a much better option IMO if you don't plan to pull the head, though I can see how on some models they could be tricky to install. Many of these have knurled outsides that when combined with a high temp RTV and swaged into place per instructions (they usually include a tool to ream the hole and then a tool to install it) are amazingly permanent. The shop vac is a good suggestion, and I believe others have suggested using some bearing grease on the reaming tool to collect the bulk of the shavings as you use it...

[oldgsfan]

It wasn't a helicoil, but an insert. It wasn't time sert, which I think is a specific brand, right? But it was an insert.

It came with a tap to rethread the hole, the insert and yes, a tool that I was supposed to put in the insert after it was in and, according to the instructions, hit it lightly with a hammer a couple of times.

I never got to that step because I had used the spark plug to screw in the insert. And there they sit now, together, spark plug and insert.

I don't think the thing will come out, though I am sure wondering what I'll face when I need to pull the spark plug to replace it next time.

At this point, I'm debating whether to leave it in as is - spark plug snug, seated -- or remove the plug and in all likelihood the insert - and give it another try.

[chuck hahn]

This...done in less than an hr and you can do it right on the bike..no pulling the head. Only change to their instructions I did was use a spark plug as the tool to thread it in once youve retapped the head. Add a few drops of red loctite and your god to go.

http://www.amazon.com/Helicoil-5334-14-Save-A-Thread-Thread-Repair/dp/B0002SRF4O