I'll agree with going into the side.

I will warn you to be careful and don't lose the woodruff key on the shut-off shaft. I dropped mine once and almost didn't find it.

Also I've been into mine several times from the side and I've never had oil drain out.

Scott

 

good call, when you pull that throttle lever, I'd grab the key and set it somewhere safe!!!!

I always park uphill or pull my left front tire up onto something so no oil will drip out.

 

I've done two threw the top and it wasn't to bad. Just looked like more work taking the stuff off of the side. The first one took probably one and a half hours to do but if I remember right the second was done in 45 minutes or a little less. There is a little pucker effect holding the nut with a magnet but it's not to bad.
Go with what you are most comfortable with. Adjusting threw the top is a cinch.
It's the best money spent on a p-pump!