What is the "extra" oil port for?

[Big Dan]

When I did the top-end and cams in my '99, I used a later cam plate and had to block off the "extra" oil port. I've never really known, just what is that "extra" port for? What is lacking in a '99 that is not lacking in later bikes? How critical is it? Would it preclude one from using these cases to build a larger displacement engine?

The reason I ask, is that I'm keeping this bike forever, but I know the motor won't last forever. Next time around, I'd like to do a "big lazy motor" as some people describe 'em. With my budgetary constraints, it'll take me quite a while to gather parts, so I'd like to start formulating a plan in the relatively near future.

[springer-]

In 99 the Twin Cam was only available in the rubber mount version.  In 2000 they introduced the Twin Cam in the balance version.  The oil port was added for the balanced version.  So the 99 cam plate became a one year part.  IIRC

[Big Dan]

Where does that port feed to on a 2000 and up non-balanced motor? It's gotta go somewhere, yes?

[a2wheeler]

it goes nowhere on the A motors 2000 and up. the case has a blind hole that matches up to the camplate. No need to plug the hole on the camplate, as the case is doing it for you. On the B motor case that hole goes to the balancer.

[Big Dan]

Aaah, now I've got it. Thanks.

[tbird]

So if I got this right. You could in theory use a 99 cam plate on 2000 and up A motors with no problem? I have a perfectly good 99 cam plate that I had thought was worthless. But now I think it could have life in a newer A motor.  Any thoughts?

[Admiral Akbar]

I wouldn't have any problem running it as long as the bearing fit was good and the gerotor section not to gouged. The one thing I'd watch out for is that the bosses are thicker where the dowels are so I'd use a 1 1/8 in allen instead of the stock 1 incher..  You might want to remove the O ring on the boss also.. The plate may not be flat there and it could possibly fall out.. Either way check it.. Max