KX 310 Gearing

[dix]

I know I posted something about this before, but I can't remember the answer. I am having my KX 250 bored out to a 310, and need to change the gearing. It has been suggested that I knock 3 teeth of the rear sprocket, which would bring me down to a 45 tooth. Would I get the same ratio by simply adding 1 tooth to the front sprocket? It came stock with a 13t on the front, and there is pleny of room for a 14t. Which is the better way to go, and does it make a difference as long as either outcome produces the same ratio? Sounds like a stupid question, but I want to get it right the first time!! Maybe I don't even need to change? Any 310 owners have any suggestions?

 

[cpmx76]

I had a EG big bore 01yz275 , I took one tooth off rr. sprocket, was best for me . good luck .

 

[Senior KX Rider]

I run a 15 on the front for open terrain, stock if it is pretty tight stuff. The 310 easily pulls taller gearing.

 

[MX-727]

48/14=3.4286 - slightly taller than 45/13

45/13=3.4615

48/13=3.6923 - stock

 

[94kaw310]

I second the 15 tooth countershaft sprocket. I run 14/50 on mine if Im in trails or tight stuff, but like the 15/50 combo. to really let her stretch her legs. What ever you choose (+ 1 on the front or - 3 on the back) the 310 can pull it, front is cheaper and easier to change.

 

[dix]

310 gearing

I chose to go with the 14 / 50 gearing for now. The stock gearing for my bike was 13 / 48. I hope I geared up enough to make a difference in top end without sacrificing the low end punch. Thanks for the advice fella's!!