| I would fit them to the original carbs as the parts you change are the main jet and the needle , i'm not sure if the needle jet is on the same on both bikes or the air jet for that matter.
I was interested in the kit if it had been cheap enough to see how different the needles were to the 600s as the bigbore kitted ones may find a benifit from having a different needle profile
I wasn't going to bid to high as I have been picking up new 600 jet kits from K&N in the States for £15.40 | 
skidlids
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