I mean 
Sorry,Dave..... I don't think that 36 is gonna work for you. How about a small simple jackshaft? You have #40/41 chain so your clutch is going to be at minimum, 10 teeth. Ok, so 10 and 36 gets you 3.6:1 and we said that's no good. So get a 14 and a 24 tooth jackshaft sprocket, a short shaft, and 2 bearings..... The 14 & 24 tooth coupled with the 10 & 36, will get you 6.171:1.... That's great! Or change the 24 to 22 and you get 5.657:1....... More high end.
Or change the 14 to 16 and have MORE high end......@5.4:1
Or change the 14 to 12 and have more low end, @ 7.2:1
If I haven't confused you yet let me know, cause I can keep swapping numbers all night.....
lolgoku That ratio works for me and my set up. If it was a 2 seater, I'd be back at 5.8:1-6.4:1......
General rule of thumb..... The bigger the number before :1 means the more torque / power it will have. The smaller the number,the more speed it will have. The average baseline gear ratio for a kart is 6:1,being on a simple yard kart with 11" tires. It's when you change the kart, ie for off road, more weight, or bigger tires..... That's when the need for a different ratio comes in. The more resistance you have (all of the above ) ,the more ooomph you need to get going and stay going. If you are using 15" tires with a CC, then you have to gear down to around 8:1. Depending on how and where you drive, you might get away with 7.2:1. Anything more than that, you're gonna need a torque converter and still need a lower ratio. Does that make sense?
My single seat yellow jacket has a modded gx160 and in the 9hp+ range. I run 11.5" tall tires, the kart and me weigh in around 300lbs. My current ratio is 4.8:1..... It's a yard kart turned street runner.
exactly..... 
You almost got it right..... 10t clutch to the 24 tooth on the jackshaft. Back to a 14 tooth turning the 36tooth on the axle.
The way you had it, would give you 2.1:1......
See , with a jackshaft, it easy to play with gearing, all the time. You only swap one gear for another. And not big tooth count differences either. If you took the time to make a couple different ratio set ups, you could easily swap out for high gears to go run the streets. Then you can swap back to a low gear ratio for romping through the mud and muck.... All it takes is different sprockets and you can make a chain to length, for each ratio set up. So, in reality, if you want to change from high to low (or vice versa), you would take off the retaining nut from the shaft. Slide off old sprockets, slide on new sprockets,then put the nut back on. Apply correct chain, and snug it all up. This can be done in 20 minutes or less..... Not that bad....
