Missing Engin Mounting Bolt ....little help

[aedi006]

GS850GLZ

So I started my valve gap adjustment today. To get into the crankcase (so I could rotate the engine) I had to remove an engine guard the PO had bolted on. Lo and behold the guards share two mounting bolts with the engine and the one on the left bottom side was just missing (#27). I immediately put a jack under the engine before playing with the other bolt. I removed the right side bolt and the funny nut (#29) fell off. Here are my questions....
The bolt I removed was not a shoulder bolt and threaded directly into the nut (#27). The threads that were inside the motor mount were all destroyed (of course). Should this be a shoulder bolt from OEM? Since I like to replace any bolt I take off with Stainless (18-8 doesn't have a terrible reaction with Aluminum) I would like the get the appropriate type of bolt. Anyone else run into problems here? I assume the nut (#27) was shaped this way to eliminate the need for a second wrench, is this correct?

[Boondocks]

GS850GLZ

So I started my valve gap adjustment today. To get into the crankcase (so I could rotate the engine) I had to remove an engine guard the PO had bolted on. Lo and behold the guards share two mounting bolts with the engine and the one on the left bottom side was just missing (#27). I immediately put a jack under the engine before playing with the other bolt. I removed the right side bolt and the funny nut (#29) fell off. Here are my questions....
The bolt I removed was not a shoulder bolt and threaded directly into the nut (#27). The threads that were inside the motor mount were all destroyed (of course). Should this be a shoulder bolt from OEM? Since I like to replace any bolt I take off with Stainless (18-8 doesn't have a terrible reaction with Aluminum) I would like the get the appropriate type of bolt. Anyone else run into problems here? I assume the nut (#27) was shaped this way to eliminate the need for a second wrench, is this correct?

The OEM bolts are not shoulder bolts, but standard bolts. The odd shaped nut for the top center bolt is known as a captive nut, meaning it can't turn or move once it is located.

I also had a missing left side engine mounting bolt underneath the crankcase on my bike. I replaced it with a standard metric bolt from the hardware store.

[bwringer]

I'm a big fan of stainless myself, but although it's very hard, it's also quite brittle. I would not replace a steel bolt with a stainless bolt in this application -- it's subject to a fair amount of stress and vibration.

Most ordinary hardware store bolts will corrode away very quickly. I'd get a bolt from the hardware store to get back on the road (a hardened one if you have a good hardware store), but I'd also order the correct (coated & hardened) bolt from Suzuki and replace it ASAP.

[Boondocks]

I'm a big fan of stainless myself, but although it's very hard, it's also quite brittle. I would not replace a steel bolt with a stainless bolt in this application -- it's subject to a fair amount of stress and vibration.

Most ordinary hardware store bolts will corrode away very quickly. I'd get a bolt from the hardware store to get back on the road (a hardened one if you have a good hardware store), but I'd also order the correct (coated & hardened) bolt from Suzuki and replace it ASAP.

The ordinary hardware store bolts that I used are still bright and shiny three years later after riding year round in all sorts of weather.