well, ducman's probably got 30HP on you, so running your stock swingarm on the sand wouldn't be a good formula for success. Hell, I had a 62HP ported stock stroke shee, and it was a handful with the stock swingarm with the 21's. I'm not sure where you're getting your power from, but honestly, my bike's a dog in 6th with 21's, and again, I got 30HP on you running the same gearing.