Oil plug washer?

[Bocash3]

Howdy. Owner of Honda dealership used the New Trail 125 I just bought to commute a few times to his dealership.
So I accepted the new untitled bike with 105 miles on it. Stated that it seems to me that he was breaking it in and the Most I could
get out of him "free" was a quart of oil with a Steel Washer taped to the top of the oil container.

He stated the washer was two-sided. Don't have it right here in front of me. Seems it has a soft side?? and a bare steel side.

He told me to put the "Sharp edge" side against the ?????????????????????? (Can't remember if it was the oil plug OR the crankcase.)

So what's the deal on this washer? I would think the factory oil plug would suffice?

Thanks so much in advance, "Bo"

 

[m in sc]

i've never seen a bimetal drain plug washer, sounds like BS. they are usually just stamped aluminum, and one side will always be rounded to to the punching process. it can go either way.

 

[Low-gear]

Soft side definitely needs to face the pan. I recently installed one the wrong way and there was a small leak. Flipped it around and no more leak.

 

[SneakyDingo]

Those OEM crush washers can be expensive. Pretty sh*t freebie to have that and a quart of oil considering how many fees they slap on. I've only ever seen single metal crush washers made out of aluminum or copper for automotive use.

RE: direction, IMO if direction was important, Honda would have listed it in their manual. If you need help, it's 2-13 of the 2021 service manual. No mention of orientation. I'll add the additional context that these are the same people who on that same page show oil strainer screen orientation and on 3-22 specify an orientation for the band clamps on the fork boots.



There is a part number for the crush washer (90407-259-000) but it's a generic 12.5X20 aluminum looking crush washer. Looks like this. Never thought much for orientation, but like a magpie I like shiny objects and surfaces so I've always installed it with the shiny side facing the bolt head. Seems to be working so far.

 

[m in sc]

use a stat o seal, easier on the threads anyway. .02

 

[Bocash3]

THANKS, Low Gear, Dingo and others. Will take note.

Guess my question is also Why was I given that washer? Have not attempted to change oil yet at only 116 miles, but question why
a washer should be replaced................or installed. One would thing the existing oil plug should work fine when replaced.
But since the dealer gave and insisted I use that washer, there must be a valid reason.

Confused in Western NC............................. and THANKS to all!!

 

[m in sc]

its suggested you replace the crush washer each time is why. I dont... but.. its the 'proper' way.

 

[SneakyDingo]

<stuff>

Why was I given that washer?
You should be replacing the washer each time you change the oil. The washer helps create an effective seal and is "destroyed" on each use. Note that there's a lot of flexibility in the interpretation of that as a hard requirement, based on a few things.

Why should I replace a washer?
It's something that's designed to deform under load to perform a task. If it can still deform more and perform the task, it doesn't need to be replaced. But if it can't deform anymore, then you should replace it. It's kinda hard to tell without experience with this design of crush washer, so the easier / safer statement is to say replace it every time. There's some bolts that are the same way - "when you tighten it, legally it's safer for us to say to replace the bolt every time, but you don't really need to."

Why should a washer be installed?
Related to the creating an effective seal between the threads of the plug, the threads of the casing, and to a much lesser extent to me, the interface between the sump bolt head and the engine case.

IMO the crush washer does two things - at a very zoomed in level, stuff isn't really that flat. The engine casing and the plug are both kinda "rough", and when you tighten it the crush washer will fill those gaps. By filling the gaps, it will make sure there's a good seal at the very zoomed in level that oil won't leak past, and you also won't have to tighten things quite as tight to achieve the same result. IMO while I wouldn't install a plug without a washer, I think this is less important nowadays when you involve good enough quality control mechanisms.

The second, and more important reason to me, is that the crush washer helps prevent ham fisted mechanics doing expensive damage to engines - same reason as me using a torque wrench. The crush washer will deform (hopefully) before the engine casing does as I tighten everything. In short, it's a cheap protection effort.

As a practical example: My plug is a steel Gold Plug MP-01. IIRC my engine casing is Aluminum. My crush washer is both a design that will deform but also a softer grade of aluminum. If I was to tighten the drain bolt, the washer will deform and squish. If I keep tightening it, eventually the engine casing threading will give (before the plug does, because the plug is made of a harder material). That's a much more annoying problem to solve. So the $2.50 crush washer helps protect the ~$160 engine case.

 

[Bocash3]

The engine casing and the plug are both kinda "rough", and when you tighten it the crush washer will fill those gaps.

****************************

Dingo...........the Above explains it all....... Thanks for all your detailed notes and time. I've always been
mechanically minded as far as taking things apart and getting them back together (most of the time )
But details like yours help make confusion into good sense.

 

[Bocash3]

Is BELOW the Gold Plug I could use to catch steel/iron particles in the Trail 125?

Honda Super Cub C125 GoldPlug Magnetic Oil Drain Plug 125cc Street Bike MP-01 | eBay

Don't let this oil change go by without installing a magnetic drain plug. Your oil filter can't catch everything! Since the oil in the sump runs through the oil pump before it hits the filter, the filter can't really protect the pump.

www.ebay.com

 

[SneakyDingo]

The science of smoothness can be incredibly interesting. XKCD does a great analysis of "how smooth is a bowling ball, really?" and it kinda highlights how things we think are smooth aren't really smooth. Knives too - obsidian knives vs. steel knives.

RE: the gold plug, that's the one I know works for the JA55 engines and I've been told it also works for the JA65 engine. So like... should be fine to order, but maybe hold on to the receipt? It's not an essential item. It's definitely a luxury purchase.

 

[m in sc]

CHEAPER OPTION WITH A STAT O SEAL INCLUDED. I actually have a few of these. I was just going to buy some washers but this was so cheap i just bought the whole thing instead.

Magnetic Drain Plug Oil Sump - thread size M12 x 1.50 - 12mm x 1.50 (PSR0103-1) | eBay

Thread Size - M12 x 1.50. Just wipe off this black gunk, replace the sealing washer with new washer and re-install your magnetic drain plug back into your oil pan. Do this during every oil change and you can continue to have the maximum protection for your engine!

www.ebay.com

 

[dmonkey]

Too long of a protruding magnet can hit the oil filter screen, something to be cautious of.

 

[m in sc]

lol. that fits fine. also, its nowhere near the screen. (depth wise).

 

[dmonkey]

The stock drain plug isn't too close, but with a magnetic tip added and the same thread length, same thickness washer, it can certainly end up near it depth wise.
Here are some photos from the UK Facebook group of a ridiculously long magnetic tip, and the oil strainer screen removed from its slot, to illustrate the concern on a JA55. Obviously just touching the screen would be different than blocking the hole into the filter screen box, which this ridiculously long magnet did resulting in oil starvation.

 

[m in sc]

and the one i linked doesn't come anywhere near the screen, as i said. ( i put it in when i had my clutch cover off a few weeks ago) that drain bolt in the pic is ridiculous

 

[SneakyDingo]

If I pulled that out of my bike I'd wonder if it was really a drain plug or if the plug was just happy to see me.

 

[dmonkey]

Glad you checked. I'm just saying it's something to be cautious of, not a problem for most of the magnetic drain plugs marketed for the Honda 125ccs. Worth checking the length of any generic one with the magnet installed against the stock bolt to see if it might push into the screen or worse.

He wrote that it lasted a whole 2.2 miles with that plug in. Rough day for someone trying to add extra protection to their engine only to get the opposite result.

 

[SneakyDingo]

This thread was super convenient timing; I usually do my changes roughly every 2100 mi, and I just ticked over 2150 mi since the last change. I used it as a good excuse to snap a photo of what the crush washer looked like compared to a new one. This is the dull side that faces the engine - if you look closely, you can see some rings imprinted into the crush washer on the left, while the brand new one on the right doesn't have any. The reverse side (facing the bolt head) was indistinguishable from each other. So this means at least on the engine side, there's a bit of a lip at the engagement point.



And just because it's been a while since I did some CAD modeling and I needed the practice... If you were to CAD model an approximation of the setup, it would look something like this. Holes, shafts and heads are the right size, but the thread TPI is not the right TPI (doesn't matter, this is for illustration purposes only). At the very zoomed in level, when threads engage, it's not like it's occupying 100% of the space around the screw, the head-facing portions of the threads are pressing against each other, and there's "gaps". The crush washer deforms to create a nice, tight seal between the bolt head, so even if the oil makes it past the threads, it will get trapped there.


So if you used a new washer, and you changed your oil, wiped everything down and see a drop of oil on the plug because you err'd on the side of "looser is better", tighten it an unscientifically "tiny bit more", wipe it clean and it will crush the washer a little more, seal slightly better, repeat as necessary and you'll eventually stop losing oil via the sump plug.

 

[m in sc]

as a rule, straight threads are never a seal, period. there either has to be a taper or a crush washer or o-ring to seal. this is universal, and one of my biggest pet peeves is seeing somebody apply teflon tape to straight threads, its one of the most ignorant things to do in any application.

the reason i use a stat o seal (or bonding washer) is that it: 1: is much easier on the threads. 2: the buna seal will always deform easier and fill in any imperfections better than an aluminum crush washer. 3: you -can- apply regular bolt torque numbers when using a bonding washer as there is a positive seat with the outer ring. 4: they are by design, reusable.

I would strongly recommend using them.

why then do aluminum crush washers still get used? cost. its a stamped ring of -slightly- softer aluminum that costs a fraction of a cent to make in mass production.

https://www.mcmaster.com/93786A200/ (or similar)