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Discussion Starter · #1 ·
I went to install a cam in the bike today and things took a left turn on the very first step. I went to remove the crankshaft hole plug and things took an immediate left turn. The plug uses a 10mm allen, and I have a set of metric hex sockets so I figured I'd be good. I'm no pro, but I know these can be problematic if you don't get a good purchase on the fastener. So I push the hex into the plug with one hand and slowly turn the ratchet with the other. I feel it start to give way so I stop to see if I can just twist it off by hand the rest of the way. Then I see the hex has stripped out the plug!

I look up on the internets and apparently this is not too uncommon. Some people drill and tap for two bolts that they then use to turn the plug out, but I saw one guy said he used the tool from his grinder with two pins. I have a grinder with just such a tool so I drill a couple of appropriate sized indentations and tap the tool into place with a hammer to make sure it gets a good bite. Again I press against it with one hand and push down with the other. It also starts to rotate and then comes loose entirely, but it is the tool that comes loose, not the plug. I look down and one of the pins of the tool has bent! I straighten the pin with a pry bar and then drill the holes just a touch more to get more bite. I repeat the process (except no more drilling) a couple times, sometimes using a hammer in attempt to rotate the tool. When I'm about to throw in the towel, I feel the plug loosen. Hooray! I'm able to twist it out the rest of the way by hand.

Removing the plug, I see the o-ring is torn as I had drilled into it, and there is a small nick on the casing. I'm hoping this will not be a problem. I will likely hit it with a small file to ensure it's not burred before I replace the plug and the o-ring.

My bike is a little over 2 years old with about 1300 miles on it. I've done a little off roading, but nothing serious, and it has always been garage or shed stored. I'm kind of blown away at how mushy the aluminum was and how tight it was put on. Must have been some "gorilla" assembling this Monkey....

The offending plug with the two new holes:
20210711_174014.jpg

Backside of the plug. You can see I went all the way through.
20210711_174025.jpg

Destroyed o-ring:
20210711_174005.jpg

Strangely, the nick wasn't where I was drilling. I put the two holes at 12 and 6 o'clock, but the nick is around 10'oclock:
20210711_174039.jpg
 

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2020 Honda Grom
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Mine didn't strip, but I did buy Titanium plugs from DingerBuilt so that I don't have to worry about that thin flange breaking off on the timing mark plug.......again.
 

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Discussion Starter · #3 ·
I just did the timing plug to see if I'd ruin it. Fortunately this one came free with no issues, though it was difficult to remove it from the hex socket. Hearing that the flange was fragile, I gave it a few whacks with a pry bar towards the center. Those plugs from DB are pretty expensive, but might be worth it to avoid a repeat. Do they come with new o-rings?
 

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I don't think so, but honestly don't remember. I think that someone sells cheaper options, but Titanium is Awesome! Lol
 

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I’m running Kitaco machined aluminum plugs. I don’t know if they are any stronger, but they look good…lol. Fortunately, the removal of my stock plugs was uneventful.
 

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People often use these interchangeably, but it is worth noting that ideally when someone says something "stripped" they are talking about the threads of the fastener or part being damaged, or 'stripped' off, whereas what you are describing would be a fastener that is "rounded". Since you included pics there is no confusion, but in text-only discussions it can be ambiguous as both failures are very common and occur in similar situations.

The nice thing about a weak/soft fastener is that it will fail before it damages the soft material that it is threaded into, that's part of the reason that factory filler caps and dipsticks are often threaded plastic, they are too soft to wear the threads of the case cover with frequent use, they discourage over-torquing, and when the plastic eventually wears out, it is easily replaced. In this situation, if you replace the failed plug with something much harder, you take on some risk stripping the threads from the stator cover, rather than just rounding the comparatively cheap and easy to replace plug. With an aftermarket product of a different alloy, you also run the risk of dissimilar metals inducing galvanic corrosion. That's not to say that there's any real-world problems with aftermarket plugs for people who use them (I'm using an aftermarket stainless-steel magnetic oil drain plug myself), but it is good to be mindful of the pros and cons.
 

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Discussion Starter · #7 ·
Good point on something stripping vs. rounding.

I picked up the titanium plug set from Dinger. In this case, yes, it's nice insurance to prevent the plug's hex socket from rounding out. As long as you don't cross thread it or really reef on it when tightening, it shouldn't have a tendency to strip any more than a properly tightened aluminum plug.

I disagree that it was "easy" to replace, or I'd have just ordered a $15 OEM replacement. I did not want to deal with that again. Maybe easier than the stator cover. Coincidentally, I stripped out an oil drain plug on a Miata many years ago - or rather I stripped the steel seat out of the aluminum oil pan when tightening it. I have been extra careful with oil drain plugs ever since.
 

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I disagree that it was "easy" to replace, or I'd have just ordered a $15 OEM replacement. I did not want to deal with that again. Maybe easier than the stator cover.
Apologies, I intended "comparatively" to modify both "cheap" and "easy to replace", referring to the ease with which a replacement plug could be fitted compared to removing and replacing the stator cover and gasket.
 
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