14mm - 1.5 oversized drain plug

[dyoung]

'83 GS850G, been doing some work on my bike and I accidently left my petcock on prime for about a week so I decided to change the oil and filter even tho my oil didn't smell like gas or the gas tank didn't seem to drain at all (petcock problem??). I ended up stripping out the oil pan so I after reading on the forum I thought i'd try the oversized plug for it. my local Napa only had a 14mm - 1.5 pitch, is that going to work for the re-threading? put some grease on it and advance and back up and wipe?

[Steve]

NO.

Go to Auto Zone or Advance Auto, find the correct plug.

You are looking for 14 x 1.25 probably in a +1 size.

If you switch to a different thread pitch, you will greatly compromise the strength of the threads, as you will be cutting through them with the different pitch. The proper-pitch oversize plug simply cuts a little bit deeper, to regain the strength that is supposed to be there.

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[dyoung]

Thanks Steve, thats what I was thinking. then you just put grease on the threads and go in a bit and back out, wipe, and keep doing that until your all the way in correct? also, with my gas tank off and set to prime should gas be leaking out of the petcock?

[Steve]

Thanks Steve, thats what I was thinking. then you just put grease on the threads and go in a bit and back out, wipe, and keep doing that until your all the way in correct?

That sounds good to me.

also, with my gas tank off and set to prime should gas be leaking out of the petcock?

No, it should not be leaking out, it should be POURING out.

If your tank is off the bike, why is it set to PRIme? That is the setting that bypasses the vacuum-activated ON/OFF feature.

You should have the petcock set to ON or REServe.


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[dyoung]

It's not on prime, it's on the ON setting. I was wondering to test it out because like I said the week I had my bike stored on prime I don't think any gas drained out, or at least not much at all. I'm just changing oil to be safe

[dyoung]

A little confused now, called AutoZone and they have a 14mm - 1.25 but not oversized and he looked it up and said that he can't even order and oversized plug in that size. Will the 14 - 1.25 regular work then?

[Steve]

A little confused now, called AutoZone and they have a 14mm - 1.25 but not oversized and he looked it up and said that he can't even order and oversized plug in that size. Will the 14 - 1.25 regular work then?

I could have things mis-remembered, it might actually be a 1.5 pitch.

Just to be sure, take your drain plug in and have the threads checked to see what pitch they are.

Whichever pitch you have, you need an oversize bolt, another standard one will not do.

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[dyoung]

I'm going to get the pitch figured out after work tonight, i'm hoping its 1.5 because they have an oversized 14mm plug there for $3. Will I have to drill out the old threads to re-thread this new plug or does it re-thread just by advancing it into the pan?

[gearhead13]

The oversized drain plugs are made to make their own threads as you screw it in. Make sure it goes in straight.

[BassCliff]

Hi,

Here is my experience.

Stripped Oil Drain Plug Repair (PDF)

It's working fine until I fix it permanently with a new oil pan, or perhaps a time-sert.

Thank you for your indulgence,

BassCliff

[dyoung]

Thanks Guys, I believe I fixed it even tho it took me awhile to get the piggyback bolt in straight. I'm putting oil in tonight so i'll see how I did. does anyone know if an oil pan from a GS750 would fit my GS850G?? theres one for sale that I could use as a replacement but not sure of the compatability of them

[Caseyuconn]

Just my 2 cents. I recently had the same issue with a stripped plug. I used the Heli-Coil option but opted to take the pan off the bike in an attempt to do the repair correctly.

I tapped the hole using the provided slightly oversized tap and inserted the heli-coil,seemingly easy process. However when I looked at the inside of the pan I noticed that the aluminum rib around the drain plug hole had cracked away from the pan. This small peice of metal was anxious to jump off the pan and get lodged somewhere in my engine so I elected to replace the pan with a unused NOS one.

I wouldn't have seen the internal damage to the pan if I didnt remove the pan. Just an FYI.

[dyoung]

Yeah, I was thinking about that. It sure would have been alot easier to put the plug in. Did you have to drop the exhaust to get your pan off?

[Caseyuconn]

I did not because I have the 4 into 1 V&H exhaust. I took off the rear muffler part of the exhaust but did not touch the header for fear of breaking a bolt. The pan wiggled right out.
I paid $100 for a brand new NOS pan. The heli-coil kit is +/- $30.

Additionally I put the drain plug in off the bike and got proper torque with a torque wrench. With good care that pan should last another 30 years.

[bwringer]

The drain plug threads are 14 X 1.25. I can't say for sure whether that applies to all GS models.

That's the same thread used on many spark plugs (including the plugs used on most 8V GS models), so thread repair kits are easy to find. Helicoils tend to come out with the plug, so it's best to use a solid insert for spark plugs and for drain plugs.