85 XT600N Oil Tank Leak
 

I've recently returned this bike to service after a long restoration. It is now my street bike and I'm loving it. But one irritating problem persists. The oil tank leaks from the drain hole. I tried replacing the drain plug and copper washer with new OEM, but to no effect. It doesn't leak until the tank comes up to temperature, at which point it spouts a regular drip that slowly drenches my swingarm and chain guard in hot oil. I tried wrapping the plug in silicone tape, but still the leak persists. As far as I can tell the tank is sound and not cracked. Any suggestions? Has anyone else encountered this problem? I am considering having the drain hole sealed by a welder, on the assumption that I would still be able to drain out all the oil from the crankcase.

Thanks for any comments or suggestions.

The sealing surface may be chewed up or not flat anymore , drain the tank and check .Then flatten it down with a bit of fine emery wrapped around a flat piece of glass [ or something similar that is very flat ] or use a fine corborundum stone
There are some washers available called Dowty washers [ in the UK anyway ] that have a double rubber seal on the inner circumference , they work very well at sealing troublesome joints .
Or it could be a small hole adjacent to the plug that gives the appearance of a leaking joint .

Oil running to lowest point (drain plug)?
 

Hi,

When I had a similar problem with my 3AJ Tenere it turned out to be a leak from the outlet pipe, the oil was sneeking down to the lowest point, the drain plug and misleading me.

Is it possible that this is happening on your tank too?

Mark

You could remove the tank, and pressurize it to 5 PSI, and submerge in a bucket of water to confirm the leak source.

Thanks for the comments. I fixed it with a Stat-o-Seal washer, which is much like a Dowty washer, but sold in the US. It replaces the standard copper washer. A 5/16 fits the 8m drain plug.