Evening Fella's, Name is Jeremy...I'm the new guy here but thought my first post should be one to offer help since i have found much help on this forum! I have a 2005 Sportsman 800 that i bought used a few weeks back for cheap...reason being, it had a ton of issues. One of which is a non-functioning fuel gauge (doesn't even show in the display). After taking everything apart, i found that the sending unit was bad. The circuit board itself had worn out. Since there are no replacements available aside from a new tank assembly at a cost of $750...i decided to find another way of fixing this issue. Especially since i only paid $800 for the 4 wheeler to start with! So, listed below is my fix....
You'll need a 1965-early 90's chevrolet sending unit. I used a 1990 Chevrolet K1500 4.3 unit as thats what was in stock at my local advance auto. Mine was $45 with an online discount but other cheaper options are available if you don't mind to order and wait. The main thing is to be sure you have a 0-90 ohm sender. Factory polaris is 5-90 ohm so 0-90 is close enough to work. It may just show empty a bit sooner than it would with the original unit.
You'll also need decent fab skills because the new sender won't just drop in. There are two ways i considered to attach the new sender...1. cut and weld the new bracket on to your pickup tube. 2. Make a few spacers and screw the new unit to the existing bracket on your pickup assembly (this is what i did...i retrospect...i would have disassembled everything and welded the new bracket on). I was able to use the arm and float that came on the new unit as well which takes care of another problem on the 800's...saturated float.
Getting the new set up back in the tank took some work but it did fit with some patients. Once i had it all back together...i added fuel and watched to be sure the gauge functioned as it should. Honestly, it is more accurated than i really expected! I would say its very close to factory. Anyway, if you have the tools, know how and time...this may be the fix for you instead of spending $750.