Hi Scottie,
The scavenge oil pump is located behind a small cover plate facing forwards on the edge of the timing cover, a 5 minute job to remove it by undoing four small bolts which hold the cover plate on. the pump can then be pulled out for inspection and / or replacement. The feed pump is to the rear edge of the timing cover and a bit more fiddly to get at, but can also be got at quite easily if required. If checking both pumps, make sure the biggest one is at the front, if not, this would cause the troubles you describe.
There can be a few other causes for your problem - some that I have come up against with the twins include:
Wrong type of timing cover gasket [will fit, but oil holes different]
Wrong type of timing cover
[as above]
Worn oil pump and / or seating
Blockage at the timing cover / crankcase interface, where, on some machines the scavenge oil has to pass through a 90 degree turn in a channel that is very short and shallow [saw gasket goo blocking one once]
At the very worst - the big 'washer' that fits outboard of the main bearing in the crankcase is your timing side 'oil seal' - if this is damaged, or the main bearing inner race on the crank has crept inwards [should be flush with end of crank when fitted and not fully home against the crank web], oil will pour into the crankcase and the scavenge pump will struggle to keep up because oil 'waiting' to be picked up from the timing chest and returned to the 'tank' will instead go back into the crankcase in addition to the oil being pumped in via the feed pump. this will empty your 'tank' and fill the crankcase, causing oil to try and escape any way it can.
If your primary case is filling, one thing's for certain - not enough [if any] oil is being pumped out from the crankcase, so it is possible it may be any of the above.
If I think of anything else, I will get back.
B.W.