Rejetting, how to determine what size new jets?

[xschris]

Yep they will cause air leaks. Remember there are 4 of them, two for each carb.

 

[XSLeo]

Orlen, I don't know what exhaust you have or what you are changing it to, but the change can have a large effect on the tune of the carb.
If your new exhaust has significantly less restricting it will lean out your adjustments.
So get it close, then change the exhaust for final tuning.
Leo

 

[Orlen]

Gotch XSChris!! Will Do

XSLeo the PO had removed the stock H pipe and mufflers and welded on Honda mufflers - So I am currently 2 into 2 w/o the H pipe. The exhaust I plan on getting is the same design:

http://www.ebay.com/itm/Yamaha-XS40...Parts_Accessories&hash=item25893d31a3&vxp=mtr

So I figured it would be wise to wait till I get the current configuration ironed out before putting a nice new shiny set of pipes on!