Long Engine mount bolts 250R - Heat treatment

[Leevvii]

Im looking at making the longer Engine mount bolts on my 83-250R as they are not available from honda/partzilla etc anymore, I assume they would be high tensile bolts, can anyone tell me the Heat treatment method i can use to achieve the hardness required for these bolts, or, are they available as an aftermarket set anywhere?

[El Camexican]

I have no idea what the dimensions, or strength of the factory bolts are, but if you look on Allan’s Fasteners .com you might find something that works in either a hex head, or a sockets cap.

It’s unlikely that the factory hardware would be stronger than Gr. 5, so if you did have to make them 4140 would be plenty strong and you shouldn’t have to heat treat them.

If you get tempted to go with SS I would suggest not to. They are about the same as Gr. 2 and I’ve broken them when using them for engine mounts.