At the end here are links to:

1. The Yuasa page for the YTX9 (considered the OEM battery) that I have been using over the years.

2. The Yuasa page for the YTX12 - which is of same in length and width, just 25mm deeper. The YTX9 is 105 mm, this one 130mm.

Advantages if I pull this off is that:

1. Capacity: YTX12 is 10 AH. YTX9 is 8 AH. So I'd get 20% more.
2. CCA or cold crank for YTX12 is 150. YTX9 is 120. 25% better.

I'm also hoping that bigger battery will also translate into it lasting a bit longer. Seems that batteries die out on me every 2 or so years even though I have it on a solar charger tender during all daylight hours.

Being pretty DIY, I'm capable of modifying the battery box since it's plastic and so easy to cut, etc., but... the base of it would then be that 25 mm difference lower . I could probably raise the floor by maybe 3 to 5 mm since there is some leeway between the top of the battery and its connectors and the box's lid.

But either way, the bottom of the mod batt box will be closer, but hopefully still far enough away from the suspension coil off of the swingarm (it's the nearest thing to the box).

I don't do crazy riding (you could consider me an old fart, I'm not a canyon carver) but everyone has to deal with speed bumps and occasional rough spots in the road where the swing arm and suspension coil will the move up closer to the battery box (how far up, hard to tell when you're in the rider's seat cuz ya gotta keep eyes on the freakin' road - lol).
_____________

SO...

Has anyone done such a modification to fit a larger battery and found it to work out -- or not?
Any pro mechanic's input also appreciated.

Thanks.

YUASA YTX9
YUASA YTX12

 

Important Update

Never mind. Talked to official Honda mechanic, he said that the extra AH and CCA could and probably would melt electrical, i.e. starter components at some point (overheat). So this is a NO-GO. But I'm leaving this thread up in case anyone else was thinking of doing something similar as a warning FYI: don't do it.