I have an 81 xj650 and i was wanting to add pod filters and straight exhaust to it. what size jets should i get to compensate for the air difference? any help greatly appreciated!

Unfortunately it's not that simple. You will also need to drill out the lift holes on the carburator slides and replace the stock needles and figure the correct height of the new needles - this along with new jets. I recommend that you buy a Dynojet kit which contains everything you will need. One thing I ran into that slowed down the process were marginal coils. Make sure you have strong coils to burn the extra fuel. I used K&N pod filters.

did the kit come with instructions that were pretty detailed and/or how difficult was it to install? my carbs are a total mess anyway (bikes been sitting for more than ten years) so i'm willing to try...

Yea the instructions are pretty straight forward. I did it and I'd never worked on a 4 way carb set in my life. Take extra care of the diaphrames, metal shavings will tear them up!

thanks alot guys for the help