How does rated motorcycle ccs work?

Specifically, I noticed that virtually all displacements of motorcycle engines are just slightly underrated. For instance, the Kawasaki Ninja 250 engine is actually 249cc of displacement. Similarly, the Honda website rates the 125cc from engine at 124.9cc. I've noticed this with a majority of motorcycles I've come across; their true displacement is slightly below their rated displacement. Any ideas why? Is this for some legal purpose?

Gift for a motorcycle enthusiast (revised)?

My dad rides a honda, from the first day of spring to the last day of fall. He rides to and from work as well as longer trips (he road from PA to NC this summer) hes a lone wolf rider and has good riding gear including a full face helmet built in with speakers for the ipod i got him last year. Good gloves, jacket, pants, boots, thermal stuff for 40 degree weather. Are there any other items i could buy him for christmas that would help him along his rides? Must have stuff that he may not have heard of? And has anyone tried those magnet strips you put on the bottom of your motorcycle to make red lights change that normally don't detect bikes and do they work?

I bought a dirt bike with a grounded off vin what to do? Ordered new parts and everything on the way

Spent almost 200$ on this and found out the vin was grounded and a honda sticker was covering it! What should I do I had the bike for days. The person signed my bill of sale not that that helps but I contacted them and told them and they said the bike was stolen and recovered by them. I did research and basically if I keep it and I get caught I'm in trouble if I give it to the police I'm in trouble like what should I do. Part out? It's hard to find another frame for the bike I have

Why won't my honda crf70 start up?

Long story short I bought it and it has compression it acts like it wants to start up but doesn't. I haven't cleaned the carb or changed the spark plug. The previous owner said he rode it two weeks ago blah blah. I did notice that one wire sleeve that holds two wires green and black were cut. The kill switch isn't cut but two of these wires are. Is this why it won't start up? Just need some suggestions

I don't know what's wrong with my Honda cbr f4i 02

I have a f4i 02. Something is draining my battery, I've been through 4 batteries in 2 weeks; I even replaced the stator and recitifier but my battery is only running 8.6 volts while at 3krpm. When I try to start the bike it just makes this loud clicking noise from the battery being low. I can put a new battery in and about a day later it will die… Someone please help. This is becoming such a headache