Information needed

[FinalImpact]

It will be interesting to see what options the welder provides. If the process nukes the bearing there could be collateral damage.

And it is your life on the line.

If it were me, I'd gut it and weld it before swapping cases and components from block to block. Roll the dice on a used bike/engine (w warranty) before swapping parts.

 

[FinalImpact]

When I tig'd the hole in the sump, there was definitely some heat needed to make it flow and not be a seeping leaker. And to the guys point in that video, there is something in our Yamaha aluminum that needs to gas out to the surface at higher temps as not getting it molten and it leaked water.

That's not to say Yama used crap metal, more to say we don't know the composition of said metal to use the correct filler so it's more of a go big (bring the heat) or go home leaking.

That was my first hand experience. So good luck!
As for the metal shell of the bearing it could probably go to 450°F and be fine. The seal won't like that tho. Over 600 Id be worried about it impacting the hardness of the bearing.

 

[TownsendsFJR1300]

When I tig'd the hole in the sump, there was definitely some heat needed to make it flow and not be a seeping leaker. And to the guys point in that video, there is something in our Yamaha aluminum that needs to gas out to the surface at higher temps as not getting it molten and it leaked water.

That's not to say Yama used crap metal, more to say we don't know the composition of said metal to use the correct filler so it's more of a go big (bring the heat) or go home leaking.

That was my first hand experience. So good luck!
As for the metal shell of the bearing it could probably go to 450°F and be fine. The seal won't like that tho. Over 600 Id be worried about it impacting the hardness of the bearing.

Just an FYI, a small air cooled weed eater I worked on had a separate cylinder and block. The two screws mounting screws kept loosening.

I wanted to use RED Loctite but the break down temp was approx. 400F. With a laser temp gun, the block was check after a WOT RUN (7K plus) and wasn't half of that (aluminum block and cylinder) temp. The Loctite fixed the issue...

Point being, I don't see internal temps being anywhere near that high on a water cooled, oil /water cooled with a crankcase of oil getting no where's near that high.

Agreed thou, disassembly and welding (or a used case) would be best, but un-less doing it yourself, labor alone wouldn't be worth it.

 

[FinalImpact]

I'm just saying a ball bearing not in use with a steel inner cage ball separator can likely handle about 450F before I'd be concerned about its integrity.
At 350 the oils going to burning, smoking, gassing out every hole it can exit. By 450 the oil be cooked on depending on how long that heat is needed.

That said if I knew there were no seal to be damaged or foriegn matter spit into the bearing I'd do it as aluminum will dissipate heat pretty quickly.
From my sump weld experience the paint was in tact 3/4" away from the weld so it didn't get far beyond 250F. And that area with a bearing in it with a bit of mass, its unlikely it would really hit 400.

One does have to wonder why there is a seal in there on that bearing. It must be for oil control.

 

[Bluesfan83]

I'm not passing the bike on to anybody and I broke it myself so I'll run it until it doesn't anymore. 2nd gear clunks the whole time and it di dnt start until the chain broke. Although after doing some research I'm going to most likely rebuild it this winter because replacing tranny gears you have to tear down the motor anyway.

 

[Gary in NJ]

I wish I had a solution for you, but all I can offer is my condolences. It's just a worst-case outcome (well, still better than having the chain wrap around your ankle). There really is no simple or inexpensive solution here. I'd hate to see you go through the time and expense of tearing down the engine, only to have the weld leak at some point. It looks like a replacement lower end is the most assured repair.

 

[TownsendsFJR1300]

I'm not passing the bike on to anybody and I broke it myself so I'll run it until it doesn't anymore. 2nd gear clunks the whole time and it di dnt start until the chain broke. Although after doing some research I'm going to most likely rebuild it this winter because replacing tranny gears you have to tear down the motor anyway.

I'm wondering if you lost a tooth on second gear (or corresponding gear) when the chain let loose. A complete trans would fix that (as you posted)..

You might want to by-pass second gear when up and down shifting in the mean time...

I lost 2nd idler gear (2-3 teeth, forgot) on a Yamaha 125 dirt bike (many moons ago) after coming off a jump on hard ground. And the chain never came off, so it does happen.