Hey guys. I actually do not own a bike, but I did recently buy a set of '99 R1 carbs to install on my '72 Datsun 510 as a fun project. Still reading? Alright, good deal .

I started disassembling and cleaning the carbs and started noticing some weird stuff: just some discrepancies between what I was seeing on my carbs and what my research had indicated.

Here's the carbs and manifold:

The needles are hollow, don't have any discernable taper, and are perforated. It may be hard to tell from the pics, but the needle has a bunch of holes along the entire length.

Then, there is no spring on top of the needle, so the needles kind of rattle around. The bottom plastic spacer is also different than what I'm used to seeing in other stuff online. It's black and it's keyed so that it may only sit one way in the slide. The needle is also keyed, so it leads me to believe that the orientation of the perforations on the needle in the airstream is somehow important.

Can anyone shed some light on this? What exactly am I dealing with here, and is this normal? I'm a little confused. Thanks for helpings out with my fun project.

Well, I found this: http://www.yoshimura-jp.com/en/products/engine/carburator.html as well as some mentions of the kits on some Suzuki bike forums, but nothing for R1s, and their web store doesn't list an application for R1s either...