Instead of boring out my 33 MM carb, my local dealer got me a new 35 MM air stryker carb for around 150 dollars. The new mid and top end power is terrific. No longer am I getting dogged by my buddies in the straight aways. The 35 carb comes with a 4.5 mm slide that is extremely rich. So I put the stock 5MM slide and 1173 needle from the 33 carb into the 35 carb. Tested and settled on 158 main, 45 pilot, clip in 3rd position. Rev pipe, boyseen reeds, open air box, and all the other mods. This is great, fast controllable power for the more open enduros and hare scrambles. When we get to the tight technical mountain goat runs, just unscrew the top and sides, and insert the 33 carb. I have been riding a buddies KTM 200 and was about ready to trade. Not now, I like the way my 220 handles in the woods and I have the speed to match the 200's and 250's.