Cracked Engine Case - Advice?

198 Views 4 Replies 2 Participants Last post by motopreserve, 28 d ago

bananaboy42

Discussion Starter · 1 mo ago

I'm a dumbass and over-torqued the oil pressure sensor. I cracked the case there and after asking a mechanic to look at, after a few rounds of JB Weld, they're unable to hot-fix the leak.

With the big disclaimer I don't want to leak oil on the track and risk injuring anyone, how do I best fix this?

I feel like some options are:

1. Engine swap
2. Remove the sensor, actual-weld it the hell shut, but that's probably not doable from the outside
3. Psuedo rebuild it (Might be able to just rebuild the bottom half? Its not like an oil drain pan that's boom 6 bolts and you swap it though)
4. ???

Any advice?

Save

1 - 5 of 5 Posts

motopreserve

· #2 · 29 d ago

Sorry to hear about the crack. Totally sucks.

You may be able to braze or weld the case. Welding can be tricky because of the unknown makeup of the aluminum. Regardless, it should be taken apart so you can ensure it’s absolutely clean before you braze/weld or the oil will contaminate the weld. So at that point, you might be best swapping the lower case.

If you find a lower case cheap (eBay) you'd still need a set of gaskets for the reassembly. You’d need that for a swap or for brazing.

Outside chance you could braze the pressure plug in place and seal the crack? That’s probably dicey.

Good luck and let us know how you make out

Save

bananaboy42

Discussion Starter · #3 · 29 d ago

motopreserve said:
Sorry to hear about the crack. Totally sucks.

You may be able to braze or weld the case. Welding can be tricky because of the unknown makeup of the aluminum. Regardless, it should be taken apart so you can ensure it’s absolutely clean before you braze/weld or the oil will contaminate the weld. So at that point, you might be best swapping the lower case.

If you find a lower case cheap (eBay) you'd still need a set of gaskets for the reassembly. You’d need that for a swap or for brazing.

Outside chance you could braze the pressure plug in place and seal the crack? That’s probably dicey.

Good luck and let us know how you make out

Yeah I don't feel comfortable welding it.

I can grab a used engine for $250 or a lower case for $100. I've swapped an engine before, never rebuilt one.

Do you happen to know if it's possible to just kind of somewhat easily remove the lower case without 20+ hours disassembling and reassembling the engine top down?

I can swap an engine in half the time it would take me to figure out a full rebuild just to swap the lower case if there's no "easy" way to do it.

I couldn't find a hack looking at the engine myself, but maybe I'm just blind

Save

bananaboy42

Discussion Starter · #4 · 29 d ago

Update - Current plan is to flip the engine upside down, maybe still inside the bike with the exhaust removed but probably with the engine removed

Then try to disassemble the bottom half of the crank case upside down. Not sure if the parts will fall all over the floor when removed though.

I think there's no way to swap the bottom crank case without having to spend hours rebuilding the engine I dunn

Save

motopreserve

· #5 · 28 d ago

You are definitely better off swapping the motor if you know it’s in decent condition. When I looked for a whole motor it was closer to $1k - so if you can afford $250, that’s a steal.

The time it will take to rebuild will be infinitely longer than a straight swap. Once you get into splitting the cases time is going to add up.

Im not sure I’m following you with the upside down plan?

Save

1 - 5 of 5 Posts

Top Contributors this Month