Location: Full time Flat Lander (northern IL) Part time "Yoopper" Western edge of U.P. MI.
I've been having a similar problem with an 800. I'm trying to find information also. I have a local Mikuni distributor for parts but he tells me they have no way of cross referencing to Polaris numbers. I found a distributor in California on the net called Sudco. I ordered a tuning manual from them. They will not make any recommendations for tuning selections.
I just looked in their manual I just and cannot find your needle 6cey6 listed. *This manual does have charts in it with dimensions and they shipped it to me on a credit card for $9.95 U.S. plus $4.95 shipping and handling. It lists various needles with their dimensions and it sounds like you are involved enough that it would be *worth your investment. You can view some of their data on the web site. I ordered from them by e-mail for the manual but you can also order parts.