I bought a 40t rear..I was thinking I might have to take a link out if I go w/ a 39t. Don't want to do that.

 

Talk to sprocket specialists, I emailed them that I was looking for a 12 tooth front sprocket for my cannibal and a couple of days later they emailed me back with a part number 5399-12 for $17.99.

 

I also wanted to go up a tooth on the front to cut down the chain slide ware.So far the new slider has done ok.It wore down to a certan poin and it seems to have stayed ther for the last few rides.
I like the stock gearing for mx with the 18inch tamers.

Would a 14/40 set up equal 13/42?

 

14/45 is equal to 13/42.Thanks for the info atc.
I may try this for my next set of sprockets.