Part 77700-04112 is NOT a shear bolt, but a regular Gr8 bolt to hold the shear plate item to the drive shaft. I would assume it could be a regular Gr8 bolt obtained locally.It is now obvious that we are dealing with products sold in 2 different countries. The US versions of these snowblowers don't have a breakdown of the serial numbers. I just checked the shear bolt part number (77700-04112) item #32, the Messicks dot com website doesn't even list this part for the BX2750D snowblower. This adds a whole new dynamic to questions that are asked about snowblowers that are made in Canada and sold in the US. I would think that a BX2750D would be the same in both countries. This situation reminds me of the automobiles that were manufactured in Canada and sold in the US where the same model car was also manufactured in the US. It was a repair nightmare since the parts were not the same because they were manufactured in Canada for Canadian production and sold in both countries. Thanks for updating the thread and we all have learned something from this for the future.
I wonder if the BX models sold in Canada are the same as those sold in the US. If not, then we could have the same issue advising on the BX tractors.
Item 7, the Gr5 shear bolt (1/4" x 1-1/4") is a standard bolt as well, obtained locally at local hardware stores. The one from Kubota is not grooved or has any special features from what I can see.
As for the BX25/BX25D, everything seems the same for both countries. Manuals are identical from what I see in my manual vs online ones.