[Wason]

Hi guys!

Have running this issue since bike came to us. It leaks a bit or "sweat", but as you see, it is around oil. I have been replacing the washer two times and putting teflon tape around the thread - doesent keep the oil away. I did not found the right Nm for the plug either.

Some experts doubt there might be just a bit microfissure in block, but if that's right, how do you fix that?

Do you know anything similar issues or what you recommend to do? I haven't been concerned because the bike is not leaking down any oil, but it still bothers me from time to time.

Appreciate your help!

-Daniel

 

[Wason]

Firstly, thank you - all of you!
Secondly, I need to clarify: I have been investigate the leaking spot for two winter seasons. And yes of course I have cleaned that area before very clearly many times. So 100% sure is the leaking source.
And yes those plugs typically not leak.
I would like to know if you have anything similar experiences.

Thanks @BillV for your seals advice! I will keep that in mind.

 

[Wason]

if that plug is leaking why is there oil/wetness above the plug?

pull the plastics, nose and panels, wash that engine CLEAN top to bottom..

then run it, up to temp, search for leaks up front, hold RPMs to 3000 or so if its not leaking off idle, still no leak gonna have to crack it open several times to build pressure and get the oil thin..

I can see oil up on the cylinder overhang and the wind pressure wont blow it up that high and cover it completely like that just from a slow less than drip leak off that plug..

my guess/bet is its coming from the valve cover at a decent clip, how often do you have to top off?

Thanks for the message. It does not leak from valve cover or anywhere above. As I mentioned earlier, I have inspected that very precisely in two winter seasons with many many cleaning and heating cycles. Only oil what leaks quite rarely comes from that plug.
Top off only when checking valve clearance (24tkm).

 

[Wason]

It sounds like you're pretty sure this is the source of the leak.

If that is true, I would be pretty picky about reinstalling a sealing washer on it, and making sure it is clean. It's just like cleaning a drain bolt surface. Use Q-tips or scotchbrite or something to make sure you get all of the gunk out of the orifice prior to installing a new gasket washer, and clean the bolt head as well.

When I do any engine work, the parts I take off at least get a thorough top to bottom cleaning before going back on, just to ensure that there is zero dirt, dust, debris, or other bits that could ruin the motor. So if it was me, I would take the bolt out, clean it up with a tiny wire wheel on my dremel to scrape out any buildup in the threads or head, wash the bolt in solvent with a toothbrush, rinse it all off, install a new gasket washer, wipe out the threads on the engine and thoroughly scrub the mating/sealing surface with paper towels or scotchbrite if needed to get it perfectly clean, and then torque it down.

In my book, the only way to guarantee a leak fix is to first do those steps, and don't cut any of those corners. Some dirt or rocks on the threads or in the block or stuck to the washer can prevent it from sealing right, and then damage the sealing surface next time you take it off, making it hard to ever seal ever again.

In fact, for gasket surfaces on engine parts, I usually wet-sand the engine cover or part with 800-1000 grit paper on a glass or machined surface, and it makes them absolutely perfect to seal up. Of course, doesn't really apply to sealing bolts, but you get the idea.

If you did all that and it still leaks, I'd suggest replacing the bolt, and then like Bill said, maybe look into a new sealing option.

Hope this helps, I believe you if you say you've cleaned it all super well and are certain it is coming from here.
Folks, the wetness above the bolt can be due to the wind from riding the bike, this is the front lower portion of the engine, and thus why the drip pattern may look odd. I wouldn't be so quick to assume OP is not capable of finding the leak source, lol.

-Mike

Hi Mike and thank you very much for a great post!

The leaking source as I mentioned earlier is 103% right.
What confuses me a bit is that friends over here hardly believe my leaking source.

I’m thinking replacing the bolt and look after what you suggested.

Much appreciate!

-Daniel

 

[Wason]

Let us know how it goes!

-Mike

I will, but the end of season/in winter season.

 

[Wason]

Let us know how it goes!

-Mike

I tested a quick fix without removin the plug. Sealed it from outside with motor silicon. By noon today I went for a test ride - 120-150km in and outside the city. Occasionally hard driving, includin hitting rev limiter etc.
In the evening I checked the plug - no leaks whatsoever.

-Daniel

 

[Wason]

If it works, it works. But all that suggests that either the sealing surface on the crankcase or the plug is damaged in a way that the copper washer won't seal.

Yep, I agree - obviously for some reason washer does not seal properly.
Now 2 weeks after I put the silicon, I saw just a minimal oil sweat at one spot of the bolt. The mystical thing about this whole leaking thing is - either the bike stands without using it or riding it, the amount of oil leak (very, very tiny amount) is kind of same.
As I wrote earlier, 100-150km hard driving did not get any leaks - now 2 weeks after been sitting I see very minium sweat there - and actually confirmed after touching the plug (mark on finger).

I already did an oil change, and I will ride whole next season with that quick fix. Will see if it slows down it a bit.

 

[Wason]

There's a thread here where I switched my drain plug to an aluminum plug with magnet and a Stat-O-Seal. I see about one drop leaking out every 3-6 months. I've since located a fairly high end NAS seal intended for aircraft usage but have yet to use it.

Ok, nice to know. But yeah, that very tiny sweat or droplet like 3-6months is nothing to worry about.