kz1000 needle jet question

[81xsproject]

May be you guys know, nobody over at kzrider has responded... the left is out of siruis inc rebuild kit and the other out of the carbs. Which is correct? Or, does it even matter since they both have a total of 6 holes? Oh yeah, '77 kz1000 ltd

[prometheus578]

"Oh come on... you can't be Sirius!"

Can't help ya. Gonna have to wait till spring till I get a few cop bikes in. I would believe that the positioning of the holes corresponds to the active height of the needle. Just how much difference it technically makes... I don't know. There must be some difference in terms of economy, emissions, or performance, but I really doubt that you or I would be able to detect the difference. I'd always go with the originals
Styles change over the years, and a lot of times carbs are built different, but no changes are noted in the parts files. When I was doing the K&L pilot jet thread, I ordered a jet from Yamaha according to the fiche, and what I received was different than what I had in two banks of carbs!
The jet that came with the new kit... may actually be the new upgraded version. (or it may not!) yeah, lot of help, there. I think any difference would be negligable.
We have none of these in stock where I work, and like I stated with Yamaha, style can change, with no corresponding part number change.

[DiverRay]

Looking at them, the replacement will probably be a little leaner at cruise. If you notice, the holes on the original seem to be spaced evenly, the replacement has the holes closer to the "top" of the jet. That would allow more fuel at full open, and a little less at half or less.
But you know this is all a guess...
Ray

[81xsproject]

thanXS guys