Quit worrying! The little bit of vibration you are getting doesn't hurt the battery! We all use them, and they hold up well.
As for the motorcycly battery--well--they seem to work well. If they can overcome the compression of a large and high compression motorcycle engine, they surely won't be fazed by a lawn mower/ tractor engine!
That said, i replaced one with a lawn tractor battery. I didn't want to have to buy a new MC battery, as i had a good lawn tractor one in stock.
I took out the battery, then i shaped a strip of galvanised tin into the same shape of the larger battery, did several right-angle bends, a bit of cutting with a disc grinder, set the new holding strap down in the hole, and inserted the battery, hooked it up, and it worked! Several sheet metal screws hold the strap in place. You could use a strip of cardboard to make the pattern.
I must admit--if you want to be self-sufficient in owning a lawn tractor, you will need to get some hand tools, as paying somebody to do things, gets old, and expensive!

Hey Rusty!

Glad to hook up with ya again. Always get something good out of reading your posts.

You wrote: "Quit worrying! The little bit of vibration you are getting doesn't hurt the battery! We all use them, and they hold up well."

Funny you should mention that. I AM a worrier, I admit it. I worry probably too much about things I'm uncertain about, like the battery issue. I worry because like all of us here, I need the machine to start and run when it's job time... time and resources are sometimes short, and it's a pain to push the mower all the way back over to the Jeep and jump start it. I guess I worried in this same way about the other issues like tires, oil burning, blades, etc... until one by one I got those things resolved and could quit worrying about them. But you're right, I do tend to over worry about things, working on that.

But it's good to know these batteries will basically hold up under the vibration. I need to drag out my scope and monitor the alternator output to see if it's charging properly... oh wait, I'm worrying again (heheh!).

You described the process of modifying the receiver to accomodate the larger battery? That's one way to go. Funny thing: Saw an Ebay photo a while back of an MTD tractor for sale, and someone had hung a huge full-sized CAR battery off the back fender behind the seat. HMMM...

You wrote: "I must admit--if you want to be self-sufficient in owning a lawn tractor, you will need to get some hand tools, as paying somebody to do things, gets old, and expensive!"

Amen to that! It was over 30 years ago that I paid for my last 'professional' mower repair. I was mowing an apartment complex, and I screwed up and smacked the blade into a concrete irrigation pipe. Bent the shaft, oil was leaking out. I watched while this 'old school' mechanic used a large iron pipe fitted over the shaft to cold-set it back to straight. It worked, and that mower ran for a bunch of years until someone stole it (go figure!). That old guy taught me a bunch of stuff... rest is soul he's most likely gone by now... but the spirit of what he gave me lives on here. I think you've got that spirit too.

Just curious what the Montey Ward has for an engine? If a Briggs I/C twin these do develop ground problems over a period of time, consider bringing a good ground to one of the starter bolts. Sometimes the little 12 volt MC batteries are unavoidable due to space constraints. I use a Wally 12V/12A in my Honda GXV530 powered Gravely Pro 150, works fine. I use the same battery in my 1982 Yamaha 650 Maxim, spins the engine like no tomorrow.

Hey Bushleague,

Thanks for the reply. You reminded me that I need to put a dedicated ground cable on the starter. The engine is a Briggs 20hp opposed twin. The wiring schematic for the mower indicates a ground cable on the starter motor, BUT I think it has never actually had one -- they just depended on the ground connection made by the mounting bolts. I was thinking just the other day that it might be helpful to put an actual grounding strap from the starter to the chassis. I had forgotten about doing that until you just reminded me. Now it's on my list of things to do.