The problems some bikes have seem to be similar to heavily ported 6 ports, or six ports with VDI disabled.
Basically the problem you'd think with that gigantic port you get more airflow, and you'd get more power, i.e. go faster.
HOWEVER, since the aux port closes so damn late and is generally letting more air in when both ports are open all the time, it actually gets slower because velocity has been reduced soo much (I'm sure we all know this by now).

So, I read this-
http://mototuneusa.com/homework.htm

Looks like in the motorbike world people actually use epoxy to shrink intake ports down to increase velocity and gain back some power.
I figured if one was to heavily port a 6 port to the point where the sleeve was pointless to have, maybe putting some epoxy in the aux port would help gain back some of that lost velocity. (Or just go to 4 port housings...)

In this case I would imagine applying epoxy in the aux port to actually shrink it down and have it close earlier would be beneficial.

Am I on to something?

 

some filling in of the port would help. the shape of the 5th and 6th ports is lousy, in addition to the closing timing being late, and the overall size of the port being small....

Mazda has a good recipe for improvements, look at the Rx8 ports, the 5th and 6th ports close at the same time, but are WAY bigger.

you could also try opening the 3rd and 4th ports earlier....

 

Tis true.
I actually remember reading a while back a member on here made 181hp just by streetporting the center ports as well.

 

6 ports are bad at low end without the sleeves, or with them pinned open. It all depends where you want your power to be. A massive port will work like a bridge port, no low end power, all top end, the big ports are good for high end, but not for low..