need to replace the front brake reservoir assembly - fitment help

So my 83 GR650X tempter ... ugh , tempter name , needs a new front brake handle/reservoir/etc.
What other models ,like GS will fit the banjo bolt?
Looking on ebay and other places there are tons of aftermarket styles and Im liking the white plastic cylinder look .
Just dont know if the banjo diameter of my current brake lines will fit ?
Or are they universal ?
thanx.
Sorry for my ignorance ... Im an auto mechanic moonlighting as a moto enthusiast
Well ... not really . I love my bike .

If you're keeping the single caliper setup, you'll want a master cylinder with the same piston diameter (I can't recall what the diameter is off hand). But newer GS500 master cylinders work well with older GS/GR calipers and can be found pretty cheap. And since you are swapping masters, now is a GREAT time for a braided line - I can recommend this guy on eBay:

http://www.ebay.com/itm/121382183259?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

He will make a custom line for a pretty good price.

Yeah Im keeping everything .
My reservoir works and is full , I just have stripped screw heads that hold the top plate on and already tried the rubber band scenario to no avail. Figured I would just change the handle/brake reservoir/cylinder do hicky.

Like these ? - http://www.ebay.com/itm/Universal-7-8-Motorcycle-Handlebar-Brake-Master-Cylinder-Clutch-Lever-Reservoir-/181522251160?pt=Motorcycles_Parts_Accessories&fits=Model%3AGS500&hash=item2a4391bd98&vxp=mtr

that is chinese crap ,stay away :-\
why not just go next size over on the screws ?

I have to agree with XB. I'll but Chinese levers, but I'd stick to a Japanese MC every time.

Im just gonna drill out the screw head.
Hopefully there will be enough of the screw left after I remove the resi cap that I can trap it with some pliers and unscrew them. Then I can just replace the screws and keep the MC.
But it on the bench , clean it and paint it once I get the screws out as well.