GT380 / GT550 / GT750 oil pump

[jabcb]

Another question for the GT380 with the oil leak.

Am using a pump that I got from eBay.
I took the pump apart & it didn’t have a top cover gasket, so the PO had the pump apart.
I checked & both little plungers were operating smoothly. And I assembled the pump with a new gasket.

Since then it occurred to me that I hadn’t checked if the PO had correctly assembled the pump.
Looked at the field guide: http://www.oldjapanesebikes.com/GT750_f ... e/page-A57

The pistons are inserted in the valve body with the springs in first, so thats ok.
The two springs look to be the same length, so thats ok.
Both pistons operate easily & can be pushed in all the way.

Of the two piston-sized holes in the valve body, which piston goes in which hole? (Is it sufficient test if they go in all the way?)

Does the piston orientation matter? (Which end goes in first?)

[GTandcbr]

Hi
If you look at the photo in how does it work paragraph you will see the way the pistons go in which holes. The most important thing to check, if the PO has had the pump apart , is the orientation of the actuating lever. If its the wrong way around it will pump too much oil at idle and not enough at WOT!

[jabcb]

Thanks.

I see that the pistons have a raised section to keep the springs centered. The other end is rounded.
The PO has the pistons in upside down.