Crush Washer for Drain Plug

[maestronick]

Sorry to bring this up again, but I couldn't find the answer from searching BARF and Thumpertalk.

1. What is the optimum (as well as acceptable, but not quite to the spec) size of crush washer for a DRZSM's drain plug? M10 and M12 seem to be visually similar.

2. What are the fundamental differences between copper and aluminium?

3. It seems there are two camps on reusing crush washer. Can a crush washer be reused if the previous and subsequent bolt tightening occur to "just snug"? Just curious about the washer elasticity.

Thanks.
~n

 

[LongGoneJohn]

You can re-use the crush washer as long as the bike doesn't leak oil. Ideally you'd replace it every change.

I've reused my aluminum crush washer four or five times now and it's still holding just fine. I also tighten my drain plugs pretty good, I'm sure beyond spec.

I don't know what size the DRZ takes and I'd imagine that aluminum is cheaper.

 

[masameet]

Well, I did a similar thing. I thought I could use non-OEM crush washers. And without really understanding how bolts work, I bought a bunch of washers that I thought would fit the two drain bolts. The thing is M12 and M14 are the bolt head sizes and not the diameters of the threaded bolts.

Anyway the ID of the two OEM crush washers, pictured below, are approximately 10 and 12 mm. So now you know the ID and don't have to get the OEM crush washers.

And I re-used my crush washers twice. But I have no idea how many times the previous owner had re-used them. So once I got a bunch of OEM crush washers, I had to use a knife to remove the wafer thin old crushed washers from the bolts.

And I'm not altogether sure, but I would expect that a crushed washer really has no elasticity. As once it is crushed, and then gets crushed again, it loses its ability to bear the torqueing of a bolt. Which also makes users think that overtightening won't be a bad thing. But then overtightening invites the possibility of the user cracking his bike's frame. And apparently cracked frames around the drain bolts on DRZs are not unusual.

And copper versus aluminum isn't much of a matter anymore, since the value of copper now makes the use of copper as a washer unlikely.

 

[maestronick]

Thanks for feedback, Antarius. It is comforting to know your frame has been holding up despite your torquing/reusing of the crusher up 4-5x.

Masameet, thanks for your very awesome, precise explanation. Superior technical writing. Before reading this, I bought a 10-pack of non-OEM M12 soft temper aluminium drain plug washers for $5. The M12 dimension corresponds to the inner diameter. But, the outer diameter quite noticeably larger than that of the OEM washer shown in your photo. Just because I don't know how much muscle the previous owner put into torquing this washer, I will play it safe and replace it. As far as tigtening, if I don't reuse, I will torque it very slightly after tightening it with my fingers.

 

[tlthehun]

You do know that there are TWO engine oil drain plugs?

I'm pretty sure the 12 mm one is for the engine's crankcase, the 10mm is for the frame.

You should be more worried about cracking the case than the frame.

Buy a torque wrench!

 

[maestronick]

I didn't notice that 2 mm difference from my casual observation, but that is good to know. One would think the designer should come up with consistent sizing for parts of similar function like that. Yes, I was paranoid about the flimsy case.

I'm pretty sure the 12 mm one is for the engine's crankcase, the 10mm is for the frame. You should be more worried about cracking the case than the frame.

 

[Mortifer]

I always reused both crush washers on my last DRZ, put 10k miles on it changing the oil every 1k, never leaked. (not that I'd recommend this, jus sayin)

 

[masameet]

There's four drain plugs on a DRZ. Three of them are 14 mm bolts (I think) and the fourth on the frame is a 12 mm. Most owners drain the oil from two of them -- the frame and the rearmost on the bottom case. At a SM Techday Mortifer/Mike insisted that I drain from a third, the one that's just below the oil filter. Some TTers insist that that plug should never be undone, as it's easy to crack the case on tightening the bolt.

 

[redbull]

Buy a torque wrench!

Great answer!

Most people have no idea how LITTLE torque goes into drain bolts. They are not holding anything together, they are merely holding back fluid. Fluid that isn't at a very high pressure at that.

 

[YanaBanana]

Soooo, it's still not 100% clear to me - do we need both washer sizes?

And I never knew we had four drain bolts! Isn't it enough to drain via two?


On a slightly off subject, do DRZ's normally 'burn' oil?

Mine's an '06 and has ~8100 miles on it, was found to be down over a pint (half quart) recently, and again about a cup (quarter of a quart) yesterday. They only hold < 2 quarts!

I have no (visible) leaks and the bike doesn't smoke...?!?

Thanks in advance,

Yana

 

[Mortifer]

On a slightly off subject, do DRZ's normally 'burn' oil?

Yana

my last one drank oil like it was an energy drink.

 

[masameet]

I use the small crush washer on the frame drain bolt and the larger one on the crankcase bolt that's closer to the rear tire. The large crush washer also fits the drain bolt underneath the oil filter housing/to the right of the generator. Some people don't bother with the last bolt. Not sure how much but there might be at least 3 oz. of old oil there that'll contaminate the fresh oil if it's not drained.

My DRZ ran low on oil (maybe 1/4 quart) just before the most recent oil change, when I began using new OEM crush washers. The bike's due for another oil change in a couple hundred miles (so I probably should be checking the oil level ). For the last three oil changes I've been using dino oil and from now on I'm going with a synthetic (which is what the previous owner was using). Will be interesting to find if oil loss is less with synthetic oil.

 

[maestronick]

Say, if ~1/2 quart dissipates btw a scheduled oil change, would it be okay to check oil level ~mid interval and top it if necessary? I am also curious to hear opinions on the tolerable limits for dissipation, factors causing this phenomenon, and possible counter-measures.

Thx.

 

[LongGoneJohn]

Say, if ~1/2 quart dissipates btw a scheduled oil change, would it be okay to check oil level ~mid interval and top it if necessary? I am also curious to hear opinions on the tolerable limits for dissipation, factors causing this phenomenon, and possible counter-measures.

Thx.

Yes you can add oil, of course. There's a million reasons for your bike burning oil.... most are harmless.

 

[Seesm]

yeah mine burns oil it has 10K... Runs like a top still...

Changing the oil every 1k miles is overkill unless your beating the sh*t out of it... IMO.

The crush washer does not ever come back to stock size.. everytime you tighten it get's smaller.... Copper or aluminum work the sale... usually on oil it will be aluminum and on water and coolant it will be copper... (most of the time but not always)

I would stock oem ones i fyour going to replace... The right stuff for the job is never a bad thing.

Party on Wayne!!

 

[masameet]

Oh, I learned something about copper crush washers the other day from AFM199/Ernie.

Apparently a crushed copper washer can be restored to (I suppose) it's original shape or a close facsimile. So then copper has elasticity. The copper washer is placed in heated water (don't know the temperature), then allowed to cool. The metal is thus annealed. (Neat word!)