I just purchased a used 2012 Super Tenere, my first Super Ten, this week with 30K miles. I was excited to do some maintenance before an upcoming trip to Florida from Virginia and was awaiting my DMV tags. Two days after the purchase, l replaced the oil, filter, shaft drive fluid, and cleaned the K&N air filter, as well as the bike in general. Then I opted to replace the 4 plugs that were two years Old with 12k miles since last plug change.
I started with the far left plug which removed easily but had some corrosion around the hex nut. The rest were in good condition, no corrosion around the hex nut, and had nice tan coloration around the insulation at the tip.
I started to install the first plug on the front far left port.
I used a torque wrench set to 13Nm to install the first plug and managed to shear off the plug casing in the cylinder. I had To use adapters with torque wrench and this led to over tightening the plug. luckily, the insulation didn’t break off.
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As I pulled out the plug minus its casing that remained stuck in the cylinder, I searched this site and discovered this similar posting.
My heart sank when I read the estimates of $2500, etc. I decided to go all in and try and remove the casing. This was my first such experience with a sheared off plug casing in the cylinder head port. I called my stepdad who had rebuilt airplane engines in the past and he walked me through a recommended process.
I used the following to undertake the task:
Spiral Easy out #5 that I attached to a 9/32nds Socket (12 point and 3/8 inch). I used a hammer to drive it onto the easy out's square base. I then attached it to a six inch extension and had to use 1 inch adapter to get the right height to use a ratchet (I would try a square easy out in the future)
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It was difficult to align the tool in the center of the casing but after six attempts of patiently turning the ratchet ever so slowly to align it as best as I could in that tight space, it finally bit into the spark plug casing and extracted it from the cylinder plug port.
However, after the casing came out, it was scored deeply at the tip and all the way up one side. I suspected that I may have scored the port threads in the cylinder head and thus decided to use a 10mm x 150 thread chaser to clean the threads in the port. All I was thinking is this was either going to be a great success or end up in an even more expensive mechanic repair bill!
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I used a 1/4 inch driver type handle, a 10mm 12 point socket driven onto the 10 mm x 150 Spiral Thread Chaser. I hammered the 10mm socket onto the 10mm x 150 Thread chaser with a hammer with several light taps. It was on fairly snug and appeared to be solid enough to do the job.
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It took a half dozen attempts to get the tool aligned in the cylinder spark plug port. I started the rethreading effort and felt solid resistance - not a good feeling. I could not keep it perfectly aligned throughout the process and was concerned that it may not fix the problem but add more damage to the threads. I continued using a 3/8 inch ratchet and adapter until I got to a point the resistance increased more and then stopped and then decided to back it out. The thread chaser didn't want to back out using the ratchet and I switched to a driver setup (pictured) and it took several different adjustments on the angle of the 1/4 inch driver before I could finally back out the thread chaser which was still attached to the socket.
I then fashioned several 1/2 inch diameter to 1/4 inch diameter clear tubing to a shop vac to vacuum out any shavings that may have dropped into the cylinder head.
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I used this to vacuum out the cylinder head as best as possible for any shavings that may have dropped into the cylinder head.
I reinserted the new plug using a magnetic swivel 5/8 inch spark plug socket with extension by hand but had to resort to 3/8 inch ratchet to get it started. It then went in easily and seated. I then gave it a 1/4 turn more vice using the Torque wrench - I did not want a repeat.
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The rest of the plugs installed with no issue. I used anti seize and 1/4 turn past seating the plugs based on above recommendation.
I will get the bike back together later this week and see whether or not the repair to my mistake worked. Plus I will be able to actually ride it!