Topic: K1 750 Oil Pan Drain Plug Washer

[ZTatZAU]

Some years back before parking my K1 750 in 1994, I loaned the motorcycle to a relative who changed the oil and sadly cracked the oil pan by over torquing the drain plug.  I replaced the cracked oil pan with a new one from Honda at the time but didn't do much of any riding and the bike remained parked until it's recent resurrection a few months ago.

With a fresh oil change just recently I noticed a few drips from the drain plug and realized there was no crush washer on the drain plug as there should be.  The local Honda dealer had a few of the washers in stock so, I bought a couple thinking a new crush washer would stop the drips.  Unfortunately, it didn't despite carefully snugging it up a few times.

Inspecting the second new crush washer closely, I see what looks like two different materials and thicknesses making up the washer.  Is one side of the washer hard to face the plug and the other side soft (i.e. crushable) to face the oil pan?



If so, which side is which?
Thanks!  ZT

[newday777]

That's new to me.
I just go to the parts store and get 12mm aluminum crush washers or order a pack of 10 on line.( I bought a pack of 50 this last time)

[craz1]

I would say that is just the way the die broke through the material when they were stamped. I have been using these dowty seals.

https://www.amazon.com/Hilitchi-180-Pcs-Metric-Bonded-Assortment/dp/B07CKVYWD4?th=1

[MauiK3]

Maybe the face of the threaded plug?

[PeWe]

My alu washers seal the drain plugs, tank and pan.
Really aluminium and no steel washer?

[HondaMan]

There should be a flange on the oil pan's bolt. The soft washer you'd then use should be the same diameter, or larger, than that bolt's built-in flange. This spreads the soft washer out to seal up those drips.

[BenelliSEI]

Lots of places sell copper washers and they are my favourite. Under a shouldered bolt they work really well, with not too much torque. I often use these magnetic drain plugs, or bore a 3/16” hole in the bottom of your existing plug and drop in a 3/16” super magnet (it will never come out, but I set them in some red Loctite). These in the picture come from Vintagecb750.com.

[ZTatZAU]

Thanks everyone!  I appreciate your replies and suggestions and may go to one of the aftermarket or off-the-shelf aluminum washers if the second new Honda (94109-12000) drain plug washer I have, doesn't stop the drip.

I posted this question here hoping someone could clarify the instructions given to me by the Honda Parts Counter guy when I picked up these washers.  The parts guy cautioned that I install the washer with it's "squared edged corner" pointing up against the pan... or vice versa.  With a cursory look when installing the new washer, my naked eye didn't see either edge to be any more square than the other.  I was hoping someone here could confirm or reject any such notion or the parts guy's advice.

Anyway, I'll pull the plug again and install this second washer, the other way around, and see if it makes any difference.

On another note, I thought the K1 750 was supposed to have a "dry sump" except perhaps after sitting for a while... and under normal conditions, after a ride of any length, most if not all the oil in the sump would be scavenged back to the oil tank... and that pulling the oil pan drain plug would release only a small amount of engine oil.  Is this not correct?

Thanks!  ZT

[Kevin D]

Some years back before parking my K1 750 in 1994, I loaned the motorcycle to a relative who changed the oil and sadly cracked the oil pan by over torquing the drain plug.  I replaced the cracked oil pan with a new one from Honda at the time but didn't do much of any riding and the bike remained parked until it's recent resurrection a few months ago.

With a fresh oil change just recently I noticed a few drips from the drain plug and realized there was no crush washer on the drain plug as there should be.  The local Honda dealer had a few of the washers in stock so, I bought a couple thinking a new crush washer would stop the drips.  Unfortunately, it didn't despite carefully snugging it up a few times.

Inspecting the second new crush washer closely, I see what looks like two different materials and thicknesses making up the washer.  Is one side of the washer hard to face the plug and the other side soft (i.e. crushable) to face the oil pan?



If so, which side is which?
Thanks!  ZT

The washers are easily lost and the oil pans are easily broken. DAMHIK
A weld job on the cracked pan did not stop the leak. That might have happened on my very first oil change on my K0, 50+ years back.
I keep spares for the drain plug washers and also the oil filter washer.

My Impala has an oring built in to the drain plug, it has worked very nicely for 16 years, 200kMi, 40? oil changes, but I’m not suggesting to modify the CB.

The sump isn’t dry. Most of the oil is carried in the tank.
I don’t know the distance between the pan and the oil screen, but I would expect that the screen is immersed in most all circumstances. The scavenge pump lubes the trans and clutch as well as replenishing the oil tank.

[PeWe]

If oil pump is stopping oil to flow down to sump, a little less than 1 liter in pan.

I removed the pan on my K6, drained oil in pan before. Oil pump not dripping when pan was off despite oil covered the dipstick to max, or very close.

Same engine had another pump before that leaked most oil to pan when parked. Delivered like that from Honda. It had 17000km on speedo when I bought it.

No problem at all, easier to drain oil when changing. Less mess that draining oil tank can end up in

[70CB750]

I posted this question here hoping someone could clarify the instructions given to me by the Honda Parts Counter guy when I picked up these washers.  The parts guy cautioned that I install the washer with it's "squared edged corner" pointing up against the pan... or vice versa.  With a cursory look when installing the new washer, my naked eye didn't see either edge to be any more square than the other.  I was hoping someone here could confirm or reject any such notion or the parts guy's advice.

Thanks!  ZT

Washers are cut from sheet of metal.  The side facing the tool has round(er) edges than the bottom one. You might not see it - I know I would not  - but you could feel it with your finger. 

Never heard it matters for oil drain plug application, but Hondaman talks about it in his book - for C-clips in the transmission. 

[PeWe]

It feels otherwise natural to flip a washer with the flat side against the surface, rounded edges against bolt head/nut.
That's how most of my washers are placed independent of use

[BenelliSEI]

It feels otherwise natural to flip a washer with the flat side against the surface, rounded edges against bolt head/nut.
That's how most of my washers are placed independent of use

+1 to that, my habit too. Assuming the two faces are parallel, it makes no difference.

[RAFster122s]

You can buy a few copper washers then anneal them in a batch, get them cherry red on a firebrick with a propane torch and let them cool. Good for a couple uses.
 But they are inexpensive…just the cost of maintaining a bike and not having to deal with a leak…

[70CB750]

You can buy a few copper washers then anneal them in a batch, get them cherry red on a firebrick with a propane torch and let them cool. Good for a couple uses.
 But they are inexpensive…just the cost of maintaining a bike and not having to deal with a leak…

Actually that would be process for steel.  Copper needs to be cooled down rapidly to anneal. 

[Deltarider]

Because the CB500/550s drainplug is positioned a bit akward, it is one of the few bolts I use the torque wrench and I fasten it with 3 - 3,5 kg/m*. I've used all kinds of washers, including used sparkpug gaskets. None of them leaked.
* Another one is the oilfilter bolt which I fasten with 2,8 kg/m (every second oilchange).

[jonda500]

You can buy a few copper washers then anneal them in a batch, get them cherry red on a firebrick with a propane torch and let them cool. Good for a couple uses.
 But they are inexpensive…just the cost of maintaining a bike and not having to deal with a leak…

Actually that would be process for steel.  Copper needs to be cooled down rapidly to anneal.

Actually copper can be cooled down fast or slow when annealing - unlike steel it makes no difference how fast you cool it down.
John