How screwed am I (tt250)

[Jakerider]

Hey everyone. I was doing an oil change on my 2019 tt250 and while unscrewing the drain plug part of the thread just fell out. It’s leaking a ton of oil now even with the plug in as far as I can turn it. I know how to weld and could try to seal it back up, but it would be a decent amount of work to get it to the shop I weld at. Anyone have any ideas?



This image is with the piece that fell out shoved back in place (it still leaks oil)

[Megadan]

If you can get it clean enough - aka oil free - your best bet would either be to weld it on or epoxy it back in place. Then just chase the threads out.

You could use a die to cut an aluminum thread insert and then weld the hole shut and do your oil changes from the filter screen side as a secondary option. A lot of the newer CG and CB engines don't even come with a lower drain plug.

Otherwise, you need a new case half.

[severely]

Or maybe just find the next larger size drain plug and tap to that thread pitch. Good luck.

[Megadan]

Originally Posted by severely

Or maybe just find the next larger size drain plug and tap to that thread pitch. Good luck.

You can't tap into metal that isn't there. Look closely at the pictures and you will see that a chunk of the case containing a not insignificant percentage of threads that the sump plug goes into.

[Do©Hawk]

What about something like PIG high temp epoxy putty? I've heard some good stories about it from people far more mechanical than I.

[Aussie_in_MO]

You may get away with epoxy putty or JB Weld.
Surfaces will need to be immaculately clean and you'll need to be very very careful when torquing the drain plug back in after it's set.
I'd almost be leaning towards epoxying the missing piece back in, epoxying the drain bolt in place, and doing your oil changes through the filter screen side plug.
Welding cast aluminum can be a major pain due to unknown alloy, outgassing and oil contamination.

[Thumper]

Here is a completely different idea.

A replacement engine costs under $500. You may even choose to upgrade to a 249cc engine, which might cost a bit more. But the amount of work involved and chances of failure really beg the question, "Is it worth the effort?"

The only way to fix this problem with certainly is to break the crankcase in half and replace the broken side. But once you've done that, you may need to replace the seals on the ends of the shafts in addition to the gaskets. What would the parts total be? Can you find them?

And it is a whole lot of labor. Do you have bench space in a shop to do this work? Once it is all back together, it is a used Chinese engine that has been broken down and rebuilt. Sure, it can be done, but swapping in a fresh engine is much less work.

Just a thought. The quick fix (JB Weld or welding) could work. Just thinking that if it fails, what next?