Old vs New Jets

My original 78 650D1, yes I'm the original owner, has 100 main jets in it. I remember changing them 30 years ago for some reason when working at carson city kawasaki.
I got rebuild kits from Z1 and was looking at the book which calls for the 102.5R.. SO, I was looking at the 102.5 jets in the rebuild kit and I can see with the eye side by side that the orifice in the new ones are smaller.
The OEM needle is in grove 3 and LOTS thinner than the rebuild kit also so I'm not gona change that.

I'm somewhat confused or loosing memory, aren't jets supposed to get larger as the # goes up.

The bike runs just fine but was thinking of going back to the OEM size jet while it was apart just to avoid top end lean out.
O' ya the only reason for working on it was the crap gas we have ate the fuel Tee and connector tubes rubber so I changed to the O ring replacements that Z1 sells.

RobKelsey wrote: My original 78 650D1, yes I'm the original owner, has 100 main jets in it. I remember changing them 30 years ago for some reason when working at carson city kawasaki.
I got rebuild kits from Z1 and was looking at the book which calls for the 102.5R.. SO, I was looking at the 102.5 jets in the rebuild kit and I can see with the eye side by side that the orifice in the new ones are smaller.
The OEM needle is in grove 3 and LOTS thinner than the rebuild kit also so I'm not gona change that.

I'm somewhat confused or loosing memory, aren't jets supposed to get larger as the # goes up.

YES, unless somebody ran a drill through the old jets. I know a dummy who did that once..... :woohoo:

"I know a dummy who did that once....."

Is he still a close, personal friend?