Clutch rebuild problem

[clanky]

I've got 130K on my bike and the brass pivot cylinder on the clutch master cylinder wore through.  So while I was at fixing that I might as well reseal the master and slave cylinders and put new fluids in the clutch system.  I purchased Honda OEM Parts for the rebuilds along with Honda fluid. 
The cylinder walls of the master and slave cylinders looked and felt smooth with no scratches to be seen.  Seal replacements were pretty straight forward.  Filling and bleeding was pretty much a combination of pumping master cylinder and then letting gravity do the rest until fluid came out of the top of the slave cylinder vent tube.
Clutch works OK until you sit at a light for a while then it appears to slowly engage the clutch and I find the engine rpm lowering and the bike trying to move forward at which point I put the transmission in nuetral so I'm not forced through an intersection.
I've done brake bleeding on cars for years so I'm not a novice at it.
Is there something peculiar about bleeding the system that is not in the manual?
THanks for any insight !   Clanky

[SCain]

Sounds like there is still some air in the system, I would try and bleed the system again, my .02

[Ricky-D]

No, that's not air.

You're having bleed back, if you can see the fluid level is not lowering.

You have a problem with the master cylinder piston set fitting properly.

***

[Grandpot]

I agree with Ricky-D.

[clanky]

Ricky-D , I understand and was thinking that would be a possibility, I was hoping that there was a bleeding trick to this system although it seems pretty straight forward.   Is it a matter of installing yet a new set of master cylinder seals? 
I probably should have just left the hydraulics part alone but after 21 years it probably could use a rebuild. 
Do I chock this up to getting a bad set of new master cylinder seals and try another set?

Thanks for any input!  Clanky

[Earl43P]

Might simply reverse the direction of the opening of the existing (new) piston seal from < to >.
It would be the one just forward of #11 in this diagram,  http://www.valkyrieriders.com/shoptalk/GL1/gl29.jpg