oil drain plug strip, help!

I have read plenty of forums on this exact topic and have gathered some info; now I just a little more help. bike is a 2001 wr426f and i strippped the oil drain plug under the crankcase.


I either want to drill out the stripped threads, re tap, and install a larger drain plug OR go the timesert way. First I'd like to know which you folks think is better. I would like to have metal threads as in the timesert so i hopefully dont do this again (I'll also be buying a torque wrench). 


I do not have the expertise to split the case. I can take it to a mechanic, but if they are not going to split the case either, I'd rather do my own work.


If i install a timesert what size kit would be necessary? I do not know the sixe of the current hole or bolt but I assume they are factory size. How can I flush the engine with oil after doing the job? Oil does not enter the crankcase on my motorbike until it is started (this is how dry sump engines operate if I undersdtand correctly).


Any advice or information is greatly appreciated. 

Not familiar with timesert but you could do the helicoil. They are good.

I had the same problem on my wr426 when I bought it (as a basket case a couple years ago)- I ended up buying a steel Dorman 090-162 Oil Drain Plug (found it on ebay), which I drilled through the center axis and tapped for an M10 bolt (if I recall correctly)- then I put the case on a ladder so I could work on it from below (my Dad helped hold it in place) so gravity wouldn't allow shavings to fall into the bottom-end, gobbed a lot of sticky grease on the appropriate tap (to match the plug) and cleared out the aluminum shavings at about every turn of the tap (and re-greased the tap to hold the shavings). I filed flats on my "through" plug, cleaned both the threads on the plug and my new threaded hole with alcohol and coated the plug with JB-weld before tightening it. Now I have a steel drain plug seat that will never strip, and I use a copper washer on my new plug bolt to assure no leaks. It's tedious, and you really need a drill press to drill a straight hole through the aforementioned Dorman plug so that the shoulders of your bolt "plug" can seal it.


If I can do it, anyone can!



Edited by nilknarf

Not familiar with timesert but you could do the helicoil. They are good.


Helicoil are crap for thread repairs where the bolt is repeatedly removed, like a sump drain plug, as they will fail with repeat use

Timeserts are far superior for this type of  application



To the OP

Either is acceptable

If you can source a bolt for the next larger thread, and there is sufficient metal in that area to allow the increased size, then this is the cheapset way

The timeserts require slightly less extra metal as its doesn't take it out to the same larger diameter as the next size up thread, but the kits are expensive


I stripped the thread on my 450

Thread here about it http://www.thumpertalk.com/topic/1084330-left-hand-oil-drain-bolt-stripped-thread-whats-this-little-hole/?hl=%2Boil+%2Bdrain+%2Bstripped#entry11812380

Edited by GuyGraham

Personally I would re-tap. I have done it a few times on bikes, really just because I was scared of all of the negative feed-back on the timesert and helicoil methods, and since it is a bolt that is removed often I decided to do it the right way. It's not that bad of a job. I did it with a cheap tap and die set from harbor freight. I took the plug out and went to the local auto parts store and bought the next size up but in SAE instead of metric... This made me have to tap a lot smaller hole than jumping to the next metric size. So figure out your current plug size, look at a bolt conversion chart and figure out what is the closest to your current size.... Then I layed the bike over, took a drill bit smaller than the whole and got rid of the threads and then tapped it very slowly with a lot of penetrating oil. Go like 2 turns and back all the way out and repeat. Once you get a nice set of threads you will likely have to grind down a little bit of the new drain plug that way it does not get in the way of shifting inside the tranny... I had too anyways. Once you get a solid fit, and can shift, dump all the oil, flush with kerosene and do a few cheap oil changes... You should be solid!

Take your drain plug to a Napa or good auto parts store . They should have a self tapping drain plug thats just a little over sized .

I tapped mine to the next size metric, used grease on the drill bit to control some of the shavings, vacuumed out with a shop vac attachment, flushed with one quart of cheap oil, and then ran it. The M10 (I think it is) tightens much more assuredly than the stock M8.

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