Modern Vespa

I'm renewing the carb with new internal parts, and I have a question:

Why are the replacement diaphragm needle and holder I received in a kit so different from the OEM? New on right, OEM on left. See the pic below. I can clean up and reuse the OEM if I need to, but is the new needle better for some reason?

Thanks in advance.

Your new one should have a much richer light and mid load range

Your new one should have a much richer light and mid load range, if it works at all. Just clean the original

They are for a different carburetor. I'm not extremely familiar with the internals of a Walbro carb, but that's what the early GT200 had. I do know that the new parts are for a Keihin carb.

My carb is a Keihin CVK. The logo is cast into the body of the carb. Wonder if the wrong needle ended up in the carb during a previous life?

Anyway:

1. Should I use the skinny brass needle or the fat aluminum looking one?

2. The white plastic spring retainer won't fit over the needle mount peg in the old slide or the new slide I ordered. The OEM(yellowed one) fits fine.

Turns out the carb kit I purchased on a member website is generically for CVK 30 carbs, but not the GT200 carb.

I ordered before I had my carb apart, so I didn't have the parts to compare to the picture on their website. The differences would have been pretty obvious.

The more I look at Keihin CVK 30 carbs on the web, the more variations I see. They're surprisingly common on small displacement singles, even new ones.

I cleaned up the old parts, and will put the kit parts in my box o'jets, needles, and springs for my next project.

Moving on. Coolant hoses and Oetiker clamps next.