Yes you can reuse the stock needle, but only if you use stock Honda jets. The needle has a different taper than the DJ jets and any other aftermarket kits. As for the tractor muff. lots of people have used them with good results, as long as you like it LOUD. Raveer used to have one on his 4man 500. PM him and ask him what he thought of it.
Honda Foreman Forums: Discuss the latest Honda Foreman in our free Honda Foreman forums. Also talk about Honda's other ATV and UTV's including the Honda Rubicon, Honda Rincon, Honda Rancher and Honda Recon