Clattery when cold
Join Date: Feb 2012
Location: United Kingdom
County: Greater London
I've re-tapped a stripped alloy sump thread to take an oversize plug without needing to strip the engine - motorcycles almost never have removable sumps. Plenty of grease on the tap to catch the swarf, do a turn or two, wind out and wipe, regrease, do a bit more. I then ran a bit of oil down through the engine, but there wasn't any swarf to flush out. It's not going through the strainer into the engine anyway. It was a long-term fix that survived many oil changes until the bike was stolen and smashed to bits. Halfords sell a fair selection of sump plugs so it's just a matter of choosing one to suit. Copaslip the plug threads a little and don't overtighten.
Helicoil are trickier in shallow, wide holes. They can wind into the sump with successive tightening of the plug unless green Hermetite is used to cement them in position. A straightforward oversize hole seemed easier.