Leaking Oil Sump Plug on Honda 300 ATV 4 wheel drive Quad bike. Threads in the bsae of the sump (presumably alloy) seem to be partly stripped. Any suggestions for a cure please.

That depends from where the oil is leaking. One of the common leaks on older cars is rust holes in the engine sump. A temporary fix is cleaning the surface and using some JBWeld epoxy, but the full solution is to replace the sump. If the sump plug is leaking, replace the copper plug washer.

Oil leaks from an automatic transmission should be attended to ASAP, otherwise you risk expensive repairs. Less so with a manual transmission. Oil seal leaks, eg propshaft or axles, unless extreme, can be left till the next major service.

if you are refering to the oil sump drain plug you should purchase a new copper washer when you do an oil change if the old one is refitted it can leak

You will need a sump plug removal tool.
On older vehicles, this was just with a wrench.
But it could be a special key, check the plug on the base of the sump.
Take keys from ignition (as you do not want to accidentally start an engine with no oil.
Open the oil filler cap, place a container under the vehicle (could be quite a few litres of oil to come out) and remove the sump plug.
Leave the vehicle to do this for a short while, until it all stops dripping out.
Now you would want to change the oil filter.
These are in different location, but you can get a filter wrench to wrap around to remove.
PRE FILL the new oil filter with clean oil before installing (This stops any air locks when you start the engine after the change)
Hand tighten the new oil filter, they do not need a great deal of torque to screw in place. so generally a good hand tighten is enough.
You may need a new washer for the sump plug (some oil filter kits come with this in the box)
Now that the new filter is on, and the sump plug is back on. Fill the engine with the correct amount and type of oil.
I do not know the exact amount you will need.
But it is better to fill a little at a time, check the dip stick for the correct level.
When you are at the correct level.
Run the engine for a few minutes at IDLE.
Stop the engine and check the oil level again.

You should be all good after this.

Also check again after a few miles, that the sump is not leaking, and that the oil filter is also not leaking.

Sump pressure is the back pressure created within the oil sump by pressure leaking past the piston rings. The pressure is usually very low due to the venting of the sump thru the oil sump vent (usually a tube or removable plug used for adding oil). If the vent was replaced with a plug, then pressure will be very high and cause oil leak. Higher sump pressure is also caused by adding too much oil into crank-case. If you are having other problems with compressor, post again. Good luck.

If there was no problem with oil consumption before the service then the only items connected to the oil are the oil filter and the sump plug. Check around the oil filter for the leak. If the oil filter was removed leaving the filter gasket stuck to the block and a new filter fitted then the 2 gaskets will allow the oil to leak out. Check the tension of the oil filter and if it is extremely tight then the gasket may be leaking at the top of the can at the seam. conversely if the filter is not tight enough then the gasket will be leaking. Check the sump plug as there should be a copper washer under the plug but some mechanics use a fiber washer and this allows the plug to come loose and leak or worse to fall out completely.

One litre in the primary of Formula+, one liter Formula+ in gearbox, approx. 2.4 litres engine oil HD360 in sump. Look underneath and find sump. Engine oil drain plug is on left side of sump near bottom and back and is in horizontal. Gearbox drain plug is to the right side of sump about half way and points up. Torque is 14 lbs-ft with DRY CLEAN threads. Use new O rings on bung plugs, part #:11105. Warning: very easy to strip these threads.

Better off replacing the sump gasket and sump plug washer before travelling. Working in public health I have seen many motor cycle accidents caused by oil patches on roads esspecially after rain.

chemical metal / epoxy weld
you get all sorts of different types in tubes for different applications.
make sure the one you choose is suitable for all metals and is heat resistant, most are non porous.

i stupidly cracked the sump when jacking up my bike to remove the forks DOH!

bike has been leak free for a few months now- beats getting a new sump. hope this helps!

hi common fault on these is the oil switch oil runs down the block around the oil filter and down the sump as you are driving along the air draft blows it all over the place so clean it up run the engine and from underneath the car see where it is coming from the only other things on the sump that would leak are the sump plug washer and the crankshaft main oil seal at the rear of the engine it will be the switch best of luck paul