I had a major 'Oh Sh!t' today

[John]

I am working on a buddy's 79SF, carbs, brakes, forks, etc. Well today I drained the oil, and changed the filter, and added the oil. Next, I was going to remove the spark plugs, and throw a couple of squirts of oil in the hole. Well, #1 & 2 came out with out incident. #4 was very tight so I gave it a shot of PB Blaster, and went on to #3. It too was tight, so I gave it a 'Blast, and let it set for a while. After a while I went back to #4 and tried it. I was using a 1/2 in drive ratchet, with no cheater pipe. It was still tight, but it came out. It was tight all the way. I could just see the threads getting all galled up. I just knew it. Well, when I finaly got it out , the treads in the head were ok. Whew! I went on to #3. Still won't budge. I gave it a good hit with the heel of my hand. It moved, cool! Well, I started to loosen it, but it didn't seem to be coming out. I took the socket off the plug, and most of the plug came out with it, BUT, the threads of the plug were still in the head! SH!T!. That was the last thing I needed. I got to thinking about a thread I saw here about the very same thing. I was going to have to drill it out. I pulled the ignition cover off, and put a 19mm wrench on the end of the timing plate and tried to turn it. It turned easily. This bike has been sitting since 2000. I fired up the compressor, and found an old rear shock absorber rubber bushing, and it fit snugly into the tail pipe opening. I had a long nozzle on the air blower, and I gave it couple of wraps with duct tape until it fit snugly into the bushing. I opened the airflow up and turned the engine over until I could feel air coming out of the small hole in the insulator in the lower part of the plug . With the air blowing in and pressurizing the cylinder, I took a long punch and attempted to break up and remove the insulator. I gave it one hit and it blew right back at me. I then started to drill it. I kept the air blowing, and I had a magnet laying on the head, to catch the chips that blew back at me. I started with a 7/16 bit, and kept increasing the bit size until I was up to 31/64's. That pretty much removed most of the steel threads, but I didn't have a 14mm tap or thread chaser. I'll be going to the airport tomorrow to talk to my supervisors about coming back to work, and to get into my tool box and get my thread chaser. That should remove the rest of the spark plug threads. I will have the air blowing into the cylinder to blow any chips away from the hole. I do not want to pull the head off of this thing.
I'll let y'all know how I make out, when I get it done or frustrated, which ever comes first.
Wish me luck.

[MartyA]

If you must, the head is not hard to take off. Be sure you have a head gasket and a Clymers to align the cams and it will go back together fine. After replacing my cam chain mine went together easy and fired first tick.

[GNEPIG]

.. also be carful not to catch the open valve with your drilling/tapping tool, you will bend the valve
don't ask how i know about this one

[mro]

stuck plugs

hey John

Some of the engines I work on have aluminum heads. (industrial 4/cylinders) If the plugs are in them for more than 100 hours w/o someone having put antiseize on em they normally get some rust on the threads.

Stuck ones I put some miracle oil on them, let set over night. Next day ad a little more oil and warm up the engine if it runs. Once its warmed up I place a piece of card board over the radiator and watch the temp rise. 210 degrees I shut it down and start moveing the plug about 1/8 turn back and forth working it out.

Has worked over half the time with out having to helicoil the head.
Some times no matter how careful it goes bad.

When bad I always remove the head. Can't afford to screw a cilinder.


mro

[John]

Head removal

I'm not worried about having to remove the head, I just don't want to. The work is easy enough, although doing it inframe doesn't thrill me too much. I went through my engine last year when I did the Big Bore. I had the entire engine apart. Totally removed everything from the cases, and sandblasted them. Stripped the head down as far as the valve guides, and sand blasted it as well.

[LoHo]

A project bike I bought had a 18mm plug JB Welded into the #3 hole...believe it or not, that bike isn't running well...yet! Can you say "low compression?"

[prometheus578]

I got to thinking about a thread I saw here about the very same thing.

I never was able to get that spark plug out. With the broken cooling fins and the scratched bearing surfaces, I just stripped it of everything useful and chucked it in the dumpster.
By the by... I'm currently researching sand blaster equipment and would be curious to learn what media you used to blast your engine. I planned to scoot over to Harbor Fright today to look at their $299 blast cabinet... either to purchase same or steal design tips to build my own. There was a recent thread dealing with this issue and I still haven't made up my mind between the siphon gun or the pressurized container style. Thoughts?

[fxrer]

Wow, John, that’s quite a saga! Scary, too. Was that plug stuck (and #4 too tight) merely because the bike sat for 5 years? Was it exposed to the elements? Any corrosion?

It just makes me worry that could happen to mine some day. Are there any precautions, like antisieze on the threads, that make sense for an everyday driver?

[TopCatGr58]

Hey FXRer,

Mine sat outside for 9 years due to a messed up Tranny and lack of $$ and knowhow to fix it. I just used some PB blaster on them, and they came right out, no damage at all!! Of course I also didn't have them torqued in TOO TIGHTLY either, just a 1/4 turn past SNUG! I also use Champions, which use that compressible washer, vs. AUTOLITE that don't use washers!
T.C.

[John]

Problem solved

I bought a thread saver kit from Heli-coil at O'reillys, and it worked. There was no way I could just chase the threads clean, so I bought this tool that is supposed to thread into the remaining good threads at the bottom of the hole, and as it treads down, it has flutes cut into the head, and that will open the hole up to 5/8, AND cut new threads for an insert. All at the same time! It is made for spark plug thread repair. The directions say the process doesn't require drilling, but then when you read on, it says that if the lower threads are not enough to catch the threads on the tool, that you must drill the hole to 5/8, and then tap it out for the insert. The insert is different than the standard heli-coil. It is not a wire coil, but a one piece insert that is threaded in, and secured in place by a special tool, that when hit with a hammer, expands the top three threads and locks them into the head. The kit comes with three different lengths of insert, the special tap, and the expanding tool. It costs $30, and the drill was $15 at Sears, so for $45, I was able to repair the threads without pulling the head, and I saved my self a bunch of grief. I also thought to tape off the left side exhaust pipe, and the carb boot, as the intake valve was partially open at the same time as the exhaust. That really increased the airflow through the cylinder, from the air hose that I had in the tailpipe. 40 psi did the trick. I had drilling chips flying every where. No chance in hell of them falling into the cylinder. I hope this fix lasts for a while. It's supposed to be permanent.

[2fast]

That previous thread may have been mine. I had #2 break off even with the head surface. A local hi perf tuning and repair shop removed it for me for $50. They then chased the threads and it is good as new. I now am totally religious about using anti sieze paste on any spark plugs or fasteners where the metals are not the same.

[John]

2fast

I did a search and found your thread just this afternoon before I bought the kit. I had drilled the remaining spark plug out, but the hole go a little 'wallered out' so I had to go the insert route. I'm satisfied, and I hope the rest of the work on this bike proceeds smoothly. I will be using anti sieze on the new plugs that go in to this engine.

[biz78251]

need help

Originally posted by 2fast
That previous thread may have been mine. I had #2 break off even with the head surface. A local hi perf tuning and repair shop removed it for me for $50. They then chased the threads and it is good as new. I now am totally religious about using anti sieze paste on any spark plugs or fasteners where the metals are not the same.

How much was the total cost to do the repair. I just found that the previous owner must have used a helicoil in that is the wrong size in #3 because there is a gold insert and it is not long enough.
The spark plug doesnt seat all the way down I can turn it until it is about half way and then it stops turning.

[oldyam80sg]

John- I had the same thing happen a while ago and purchased the same kit from Heli-coil.Did it say to use RTV and let it sit overnight? Also when you hit the insert with a hammer and that tool, it doesnt do anything at least to mine it didnt.But the repair is solid!

[79XS11F]

I have yet to have a problem with plug removal. Even on the bike that sat for 20 some odd years the plugs came out easy enough. Those plugs had anti seize on the threads. I also anti seize and always use the torque wrench on plugs. I hope my luck keeps up and i never have an issue with messed up plugs.

Rob