i just adjusted my cam chain tensioner following the service manual step by step and now my bike (82 XJ650RJ seca) wont start!!!

Hi we need some details. Won't turn over, turns over but no spark, etc?

it turns over and all four plugs are sparking its acting like its not getting gas i sprayed starter fluid in the carb throats and still nothing.

Sorry but I gotta ask: When you were adjusting the camchain, did you have the ignition cover off? If YES, were you careful turning the motor over by the end of the crank so the wrench DID NOT scrunch into the ignition pickups (and move them..?) If that answer is also yes, then the problem is almost certainly NOT related to adjusting the camchain, as long as you got the tensioner tightened back up correctly (manual tensioner only.) Did the adjustment procedure involve loosening a bolt and nut on the tensioner unit?

i dont think i touched the ignition pickups are they real easy to move how do i know if thats the problem? and yes i loosened the lock nut then the bolt and tightened them both back down

No, the pickups aren't easy to move, you'd have had to mash into them pretty good to move 'em, and you'd know it. Just checking. Ok, good---did you use a torque wrench and/or go real easy on the bolt/locknut? If you followed the book (not hard at all) and did it all step by step, then you have a raw coincidence here, a simple camchain adjustment won't kill your bike. You said you have spark. Starting fluid isn't necessarily a good diagnostic aid. Put the petcock on PRI (don't leave it there forever) and let's see what happens.

any gas in the tank ?

the cam chain adjustment's got nothing to do with starting the bike. It'll still start, unless as Bigfitz mentioned, you displaced ignition components. Don't think of it as a cam chain related issue. Sometimes bikes like to lead you in the wrong direction. Check the obvious stuff first. Is your engine kill switch on? Is the battery topped up? Is there gas, as asphaltgecko asked.
Did you disconnect something else? Do you have a green neutral light when you've got the bike in neutral? Any fuses blown?
Check the troubleshooting section of your Haynes manual. You have one, right?

check the battery terminals for tightness... TODAY, MY 750 WOULD CRANK BUT NOT START, RAN DOWN THE BATTERY PRETTY QUICKLY, WENT TO JUMP IT, THE + TERMINAL SCREW WAS LOOSE, TIGHTENED IT,
VAROOOOOOOM ! STARTED RIGHT UP......FUNNY THING, IT TURNED OVER AND OVER, LIKE IT WAS TRYING TO START, YOU WOULDNT HAVE SUSPECTED THE TERMINAL WAS LOOSE.

turns out it was the battery i charged it and it started right up. thanks for all the help

I experienced the same thing...My '83 would SPIN right over, quite fast, but absolutely not start; was showing 8V on the dash gauge. Charged the battery fully and it fired right up, showing 12V when the key was switched on. I had always assumed if the battery were down far enough to affect starting it would be spinning slower. NOT the case.

basics .. gas...electricity...air.... ingnition key... gotta have em...

it's all about distribution of power, the juice is going to the starter & starving the coils.

Apparently. Never experienced that with a vehicle before, but this is my first real experience with electric-start bikes. Every CAR I ever dealt with would still fire even if cranking slowly.