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Oh no stripped drain bolt

8K views 15 replies 8 participants last post by  VTWoodchuck 
#1 ·
Just picked up a 2008 KLR day before yesterday. As always I went through it, new chain, new air filter, checked bolts at head pipe, changed oil and filter. Got the oil and filter exchanged, did notice that the drain plug was much tighter than I felt it should be when removing it.
Ready to button it back up, set my torque wrench for 16 lbs, started the bolt got it finger tight, put the wrench on and it just never tightened, almost felt like I put a 4” bolt in, just spun and spun. I realized right away it was not going to tighten and stopped.
I know there are some fixes, I’m thinking about just going up one size, or rethreading, but was hoping that someone who had this happen can weigh in.
Thank you.
I did put a bit of oil in to see how bad it would leak, but no leaks at all, of course I’d never ride until it is remedied.
 
#4 ·
I’ve never stripped Oil pan threads in the last 35 years of doing oil changes, I’ve used the same torque wrench for most of those changes. That has always been one of my worst fears I would strip out a drain pan.
Yes, the bolt is a 17mm as you have described, I’m certain it is the OEM plug. There was no crush washer or gasket on the bolt, so I’m guessing perhaps the PO probably torqued it down too tight to keep/stop any leaks from happening.
I’ve actually just ordered an M12 x 1.50 oversized plug that will be here tomorrow and will try that first. Unrelated, I also have a new chain and sprockets, a new front tire coming as well. I planned to do some work on the bike this weekend anyway, it’s 110 today and supposed to be hotter tomorrow and Sunday. I’ll just pull the portable AC into the shop and get some things done.
Just one thing for clarification, did I understand you correctly? Do you recommend using an M14 x 1.50 to replace the plug rather than an oversized M12 x 1.50 plug?
 
#5 ·
mine was on the verge of being stripped when i bought the bike.. i finished it off on the third oil change lol

Doesn't helps it was never drilled into the into the crankcase straight so it always leaks crush washer or not ( I just use black gasket maker on it now)

Helicoil is the way to go to fix it, kits come with everything you need to do it minus the drill and a tap wrench (just use a crescent wrench) took me 15 minutes to drill tap, clean up and get the drain plug back in.


if you use the over sized plug, good luck, i hope it takes; because you can't fix it with a helicoil to the stock size afterwards
 
#6 ·
I have no way of knowing the diameter & thread pitch of any brand of 'over-sized' drain plug.

But it would not surprize me if it were to be 1/2 inch (which is 12.7mm) or the full 14mm x 1.5mm pitch which I recommend.

The issue which I can imagine, is not removing & cleaning the self-tapping type plugs often enough & WEDGING the unsupported, soft aluminum drain plug boss wide open in a giant fractured mess!

Best to be extremely careful.
 
#7 ·
So today I spent the majority of the 109 degree day working on my bike. I took care of the other things I wanted to do first then reluctantly started on the stripped oil pan. I had not decided whether I was going to use a tap and re-thread or try the oversized M12 drain bolt. As I stated in an earlier post I had put the bolt in an it spun, but did put oil in and it had not leaked. I took the drain bolt out, as I was unscrewing it I couldn’t help but notice how tight it was and required a socket wrench to get it most of the way out. The last third of the way I was able to use my fingers to remove it.
I looked at the bolt and pan, and the bolt looks a little worn, but the threads in the pan really looked ok to me. I also maybe forgot to mention there was no washer on the bolt. So I decided before tapping or using the oversized bolt I would put a new crush washer on the drain bolt and install it. To my amazement, the drain plug tightened snug without spinning as it did with no washer installed. I’m thinking that perhaps, the bolt is too worn at the top near the head and the washer allowed it to properly catch and tighten.
I filled it with fresh oil and fired it up ran it for 10 minutes and am now watching for leaks. I’m thinking a new drain bolt and crush washer may be what I need. I’m also thinking if it was stripped bad enough, it would most likely leak.
Keeping my 🤞
 
#8 ·
Went back out a few hours later, and the plug is dry as a bone, no leaks, dribbles, or weeping. I’m calling this good, for now.
I then pulled the foam air filter to clean and oil it and found a hole burned in the bottom near the back of the air box, bummer. So now I have something else to fix. I wondering if this may be what is causing some deceleration popping? Nothing bad just one or two pops when I let off the throttle. I tightened up the clamp just below the air box, it was loose, but noticed that the PO did wrap the pipe under the air box, and “fixed” the hole with aluminum tape, which was just setting loose on the bottom of the box.
This is going to take a little longer than I had originally anticipated to get everything right, but I’d rather take the time now and do it right and not have worry about it later.
I’ve got the a Eagle Mike Doohickey kit coming, I guess I will go ahead and check the valves as well. I did the Doo before on my two other KLR’s, not too difficult. I did have help with the valves, as I had never done shim and bucket valves before. But the guy who helped me was a very nice guy, I think I found him on this site, about 7 years ago. I don’t know his user name, but his name is Darrin, he was in Paso Robles.
 
#11 ·
#12 ·
I am wondering if a previously installed Heli-Coil has stripped the Enlarged threads from the drain hole and now when the untrained eye looks at it, the threads "Look Good", but really do Not have a grip on anything?
 
#13 ·
If it was tapped for a Helicoil, then that thread would be an M14x1.5, wouldn't it? If that is true, the minor diameter of an M14x1.5 is about 12.4mm. A 12mm plug would pass in and out without catching on anything.

I'd like to know what the minor diameter of the current threaded hole is. If it is bigger than 10.4mm then it is stripped/stripping.
 
#16 ·
Caution: If you do choose to drill and re-tap to the next larger size plug make sure to drill and tap all the way through the casting because it is irregularly shaped on the inside of the case. If you don't thread through the entire case wall it will put stress on the oil plug bolt an could crack the thin casting wall. Here is a picture of the inside view of the drain hole so you can see what I mean. Best of luck.
 

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