how do the plugs look?
have you cleaned the carbs again since this issue? maybe the main jet fell out
also check float height and washer under main jet
the reeds don't have anything to do with compression. you should have at least 125 on each side I would expect. time to inspect and find out why its low. headgasket or stuck rings maybe? another question is why did it loose compression? was it ran lean and hot because of an air leak?
if you have a coolhead then you shouldn't have to do anything got the stock one besides sell it or throw it in the dumpster. what size domes do you have?
long rod you need either stroker pistons or blaster pistons and 110 rod you can use std type pistons. most prefer the 115 due to less side load but its not a huge difference. plenty of people run the 110 rod. porting however will be different for each so contacting the builder and get on the same page...
why not port them? that's the best bang for the buck I would say..
the SS pistons will work with a stock crank and timing plate and the right coolhead domes
If the cylinder isnt gouged you can take some muratic acid and a qtip to dissolve the aluminum off the cylinder wall. Then hone and measure to see if its within spec to get the same size piston. Sometimes you get lucky.
Clean the carbs, mainly pilot jet. Swap wires. See how that works
They stopped selling the banshee in usa in 06 but most others still get them till 2012
Canada stopped in 08
you need a size that fits the tires, your weight, and the type of riding your doing. providing us with that information will help. otherwise you will get freshprince answers to your vague question.