Oil drain plug stripped. Any tips?

[meat popsicle]

Originally Posted by cwc

You could search a bit and see if you find any negatives to using the oversize plugs, but I think the car guys have been using them for a while.

Even though I have taps for most sizes and could tap the hole for a 14 mm plug, I think if I had this problem I'd go with the oversize.

I will likely pass on the oversized plug idea, because I do not want to increase my chances of pushing shards into my case. I will stick with tapping out the stripped out 12mm hole with a 1/2x20 tap, using a heavy grease to trap shards during the process. What I need to know is if I should drill the stripped hole before tapping? Mike has some comments below that seem to address this:

Originally Posted by eaglemike

...

I've helicoiled a few KLR drain plug holes. Even though the hole was stripped, I still had to drill it out just a bit to get it to size so the tap would start. So double check to be sure the hole will work - if the tap won't start easily, don't fight it - drill the hole.

Form tapping is really great for some situations. It does take more power to turn the tap, too. Blind holes are about the best reason to use a form tap. meat popsicle, you're right! It's also a pain to get the chips from a cut tap out of the hole, when it's a deep blind bottomed hole, so that's another reason.

I personally wouldn't worry about less than 65 percent of threads in the hole. It's just a drain plug. It needs to keep the drain plug in place, and nothing else should be pulling on the drain plug - it's not a structural part. If the crush washer has been used before I'd suggest no more than 75 percent torque.

Sorry to be so long winded - trying to be clear and provide useful info.

all the best,

Mike

Thanks for being long winded Mike; I like knowing why. I was interested in the form tap because of my worry about pushing cuttings into my engine case. My hole is only "blind" because I don't want to disassemble my engine... I hope the cut tap with heavy grease will work to trap cuttings. But any more guidance from you and the other machinists is appreciated!

I don't have a tap/drill guide, but I was guided by a very good mechanic to use a second person to spot the other axis. I can check the right/left axis while turning the tap and the other person can stand to one side and check the up/down axis for me.

[meat popsicle]

I am about to tap out my stripped 12mm oil drain to 1/2x20. I will not be predrilling the hole since it is larger than the recommended pilot drill bit. I will not get 75% threads but some folks here think that is fine given the application - not load bearing.

One question, the tap I am considering is marked 1/2x20 UNF but my tap is not marked as "UNF". I looked it up and found it probably means "United National Fine". I could guess that means its not the tapered standard (NPT) and should be fine but I wanted to check since it is an internet order:

http://www.quickoildrainvalve.com/Se...ts.asp?Cat=208
or
http://www.jegs.com/webapp/wcs/store...50898_-1_11597

[666]

Same issue. Stripped 12mm X 1.5 on my 640. Whole thread is gone. I did noticed that it's already screwed up when I did first oil change.
I think I just go with helicoil or time-sert. Whatever is available from fastenal or mcmaster.
Why don't they put threaded bushings at the factory? With every 2k oil changes AL wouldn't hold very well.

[meat popsicle]

Originally Posted by 666

...

Why don't they put threaded bushings at the factory? With every 2k oil changes AL wouldn't hold very well.

2k oil changes? You tryin' to change this into one of those threads???

[666]

Originally Posted by meat popsicle

2k oil changes? You tryin' to change this into one of those threads???

I mean 3k oil changes with street riding and 2K with nasty dirt riding. Last month I put 3k on my 640. It's a lot of oil changes every year.

[kg4lho]

So meat, what did you end up doing on this? After looking at the closeness of the two drain plugs, it appears as though you would have to have the same size head/shoulder on the 1/2" drain plug?

My DP had two copper crush washers on it when I pulled it. I removed both washers and threaded the DP back into the hole and it pulled tight. So I then added one of the crush washers and tightened it up, filled it with oil, ran it and checked for leaks. Not leaking at this time but, it's probably only catching one thread. I really don't feel all that safe about it not vibrating out.

Why are there two drain plugs anyway?? Would it be so wrong to epoxy the 12mm DP in place and just drain using the larger one? Maybe block the RH side of the center stand so the oil will drain to the LH side? Thoughts? Thanks, Wesley

[hp2rider]

? not sure if this is what you are referring to
http://www.fumotousa.com/

I have had one on my truck (trouble free>300,000 miles last 2 trucks) never thought to use on bike because of clearance

they have a special clip

Warning: For users under extreme conditions:
If you are using the Engine Oil Drain Valve on off-road vehicles such as farm tractors and logging equipment under extreme environment (i.e. corn fields, brush areas), it is recommended that a hose clip as shown below be used for extra safety and security. The hose clip, which can be purchased at any hardware stores, will firmly keep the lever in the locked position at all times.

Originally Posted by wickedsprint

NO, it is a all steel product, and it threads into the case, it has a little drainplug of it's own even complete with an O-ring seal. N ow your oil drain is steel on steel instead of wearing out the aluminum.

[kg4lho]

Bumping it for the evening crew. Wes

[meat popsicle]

Originally Posted by kg4lho

So meat, what did you end up doing on this? After looking at the closeness of the two drain plugs, it appears as though you would have to have the same size head/shoulder on the 1/2" drain plug?

...

Why are there two drain plugs anyway?? Would it be so wrong to epoxy the 12mm DP in place and just drain using the larger one? Maybe block the RH side of the center stand so the oil will drain to the LH side? Thoughts? Thanks, Wesley

I found an online vendor that could match a magnetic 1/2" drainplug to my specs, and then I tapped out my stripped metric hole to 1/2". The only bit I would say others should do is to build a jig, so the tap stays straighter than by eye alone. With the bike on it's side, even with a spotter it was not easy to keep the tap square.

With my method I did not get (what was it again... ) 60% threads (thread depth) so I reduced the torque setting to compensate for the lack of strength due to reduced thread depth. You can try to get some synthetic washers that can deal with high heat and oil but I just ended up with copper as I recall. It's holding oil fine now.

One drain plug drains the crankcase, the other drains the tranny on a share sump motorcycle engine. So you need both to drain all the oil.