Stripped sparkplug thread

[needtorque]

Well, I would not necessarily doubt the capability of the shop.  I know that I have made mistakes on vehicles before (mechanic) and 99 times out of a hundred I catch and fix said mistake before it leaves the shop.  On occasion one gets by but I have always fixed my mistakes and that is what matters.  The shop may have had a trainee working on the bike and maybe that one slipped by the lead tech.  If they have dealt fairly with you and you trust them to do the work correctly and treat you fairly then go for it.

[TAftonomos]

In my professional opinion it sounds like the plug wasn't torqued correctly. That means with a torque wrench. This is very important because of the different thermal expansion rates between an aluminum head and a steel spark plug. Also do NOT use anti seize on an aluminum head for the same reason. The dealership screwed up. I am suprised that you didn't notice any odd sounds but then again wind noise may have covered it up. Not likely that they will replace the head unless the bike is still under factory warranty. A properly installed time sert will be stronger than factory and this is a viable option but still requires head removal. Good luck.
Jon

Curious, why would you recommend NOT using any antiseize?  How is antiseize going to adversely effect any kind of different expansion rates?

[Porsche Monkey]

I'm a master Porsche tech by trade. For some reason anti seize helps plugs back out of aluminum heads and I have seen this first hand. Use it all you want on an old iron head Chevy if you want. All of my instructors have advised against anti seize too and if I recall correctly it is listed in the service manual. If you torque a plug to the correct spec it should not back out. Granted I'm not a Ducati tech but I do speak from experience.

[Ddan]

FWIW, I use anti-seize on everything that doesn't call for thread lock, and I've never had a plug back out.

[TAftonomos]

I'm not a titled tech of anything, but have spun wrenches for the first 10 years of my working life.  Private endurance race team, then a dealership, then out on my own.  Then I got smart and took a government job!

I remember ze germans....whilst working on the 911 GTS car, you must remember to put ze antiseize on everyzing you touch !
Got yelled at a few times and then got with the program.  Antiseize goes on sparkplugs of 24 hour race cars....plugs don't back out.

Torqued threads hold the plug in (or any fastener in).  I agree, if you torque a fastener to the correct value, it won't back out.  Doesn't matter if there is antiseize on it or not.

Hell, I put antiseize on my wheel studs or lugs, never had a wheel fall off   

[ducpainter]

+3

Also FWIW many manufacturers, although not necessarily moto, require time serts in all alloy threaded applications.

There is nothing wrong with them.

[Langanobob]

I think the anti-seize question is one of those personal opinion issues.  Here's my opinion.  Not using anti-seize seems to be based on two points.  1.  It reduces friction between the  plug threads and the heads and we are idiots and will accordingly strip the threads.  2.  Anti-seize contains metal and is conductive and we are idiots and will get anti-seize on the working end of the plug and it will misfire.

The reasons for using anti-seize is that it will do what it's name intended and prevent steel plug threads from galling or seizing due to corrosion in the aluminum head, however, many if not all plugs these days are plated and don't have much of an issue with seizing in an aluminum head.  I still use a small amount of anti-seize on plug threads.  I'm not an A&P but I understand that anti-seize is required on reciprocating aircraft engine plugs (aluminum heads).

I've personally never heard of or had a plug back out due to anti-seize, but as I demonstrate every time I post I don't know everything.

[Langanobob]

There is nothing wrong with them.

DP,

Don't think there is anything wrong with them at all and as Ducaholic pointed out, they are better than the factory threads.  You may be referring to my comment about my concerns about the shop installing them.  That was based on my mental image of the tech eyeballing the hole with his $30 Home Depot cordless drill and that comment was based on the requirement for proper installation and not about Time-serts themselves.

[ducpainter]

DP,

Don't think there is anything wrong with them at all and as Ducaholic pointed out, they are better than the factory threads.  You may be referring to my comment about my concerns about the shop installing them.  That was based on my mental image of the tech eyeballing the hole with his $30 Home Depot cordless drill and that comment was based on the requirement for proper installation and not about Time-serts themselves.

I actually wasn't referring to your comment.

I was just trying to reassure the OP about the goodness of a quality repair.   

[Porsche Monkey]

My post reflected my experiences. As I stated I am no ducati tech so take it as you want it. I guess the difference may be in newer plug technology. I haven't had any problems not using anti seize.
Jon

[dlearl476]

Don't let them helicoil it.  It was their mistake and helicoils are a last resort to avoid buying a new head in my opinion.  Since they made the error I would want a new cylinder head for free.  This was no fault of yours so anything less than a bike in the same or better condition than what you dropped off to them is unacceptable.

"In theory, theory and practice are the same.  In practice, they're not."
While most of us would agree it's the shop's fault, including the shop, IME you're gonna have a hard time getting a shop to replace a head on their dime rather than do a time sert.  And FWIW, a time sert is a definite upgrade over an aluminum thread.  My biggest concern would be to make absolutely certain they removed the head to do the insert.  I seen pros do it without, by removing the intake, insuring the intake valve is open and blasting compressed air through the cyclinder as the old threads are drilled and tapped to accept the time sert, but I wouldn't trust someone who stripped a spark plug thread to get that right.

[needtorque]

Well no matter what the timesert is still threaded into alumium.  My only real concerns with this would be 1) will they remove the head to do this, and 2) how much material is around that spark plug hole to ensure no additional damage occurs when drilling the hole larger to install the time sert.  They are a bit thick.

[dlearl476]

Well no matter what the timesert is still threaded into alumium. 

Yes, the time sert is threaded into aluminum, once, and locked with red loctite.  From then on, the removal and installation of spark plugs is into steel threads which, IMO, makes it a huge improvement

[TAftonomos]

And I may have come off the wrong way.  No offense intended or implied  .  My experiance/what I've been taught only.

As with almost everything, there are many ways to accomplish the same thing.  Except for drinking beer.  Only one way to really do that. 

[Porsche Monkey]

And I may have come off the wrong way.  No offense intended or implied  .  My experiance/what I've been taught only.

As with almost everything, there are many ways to accomplish the same thing.  Except for drinking beer.  Only one way to really do that. 

If your referring to me, then no offense taken at all. I think this is a very worthwhile discussion. Whenever I go to Porsche training which is required at least twice a year, some of the best learning comes from talking with the other techs and their fixes and what nots.