I cut the spark arrestor out of my stock KTM exc silencer and tried it for the first time today. I didn't really expect that big of a difference but LOOK OUT!
I had been riding with the stock silencer for about two hours before I put on my modified silencer. My first thought was wow is this my imagination or did my already good throttle responce just improve that much. I putted around a little and it seemed like I had better bottom end, which was expected. What really threw me (literally) was the mid range. I popped a little wheelie, like normal, over a little bump. Only this time it kept coming up and before I knew it I was skidding along the ground and my bike continued on without me, minus one rear fender. OK, my next question was did the extra power cause that or was the accident due to the brace I am wearing on my finger, which wouldn't allow me to let off of the gas. Maybe a little of both. However, after dusting myself off and removing the remainder of my busted fender, I took off again and yes there is definately a noticeable gain in horse power in the low to mid range. Just where I wanted it. I sure didn't expect enough gain to have to adjust my riding a little and get used to the new power, but that is exactly what happened. My bike was already jetted on the money and ran like a champ. I paid $42.00 including shipping for a used stock silencer and then modified it rather than taking a chance on modifing my stock exhaust. Now that's some cheap horse power.
I definately recommend this modification for 200exc's. I would guess you could experience similar results on other exc models as well.
Later,
Neal