I have ridden my dad's 250R which is an 81 and it seems to have more of a kick at the top end than my 82 250R does. The 81 is bone stock and needs a new piston, the only modifications to it is 83 250R front suspension. My 82 has a supertrapp silencer with no discs and goes slower than the 81. I was wondering if Honda made any serious engine mods between these years.

Don't know about engine mods,but your engine needs a little back pressure so I would put in some discs.

but back pressure is the problem, the moment I put discs in it I can't go full throttle. with four discs in I couldn't make it up the bowl at Sand Lake with paddles.

Have you done any work to the intake side?When I piped my 85 atc250r i had to go with a K&N filter and open up the air box to make it happy.But to really make it run i have to come up with a 38mm carb.Its like putting your hand over your mouth and trying to run the 100yard dash!!!!!! GOOD LUCK

I also have an 82 ATC 250R. It's bored .0030 over, DG pipe and silencer, K&N filter, jetted, 1984 200X forks, Boyesen reeds, +2 wheel extensions, Wiseco piston. It really screams when the air box lid is off but the air box is mounted with the cover on the side so I don't run it with the lid off too often. It's for sale if anybody is looking for one.
ERIC

Retro,

I have the airbox on and it's had holes drilled in it, it has been bored out but I couldn't tell how big because I didn't clean off the top of the piston. I don't have a K&N filter yet because I don't want to melt a piston.

How is a K&N filter going to melt your piston?When i rebuilt my 85 i bored it 030 over took 010 off of the head and did a port and polish.I also added FMF torque reeds and moto pipe and power core silencer.I tried a uni filter first DON'T WAST YOUR MONEY then went to a K&N big improvement! The K&N will not melt your motor down.I didnt have to rejet when i installed mine but its good to keep an eye on your plug.