I am ready to get out in the woods with the 350 KTM, but we need to make sure it is legal first. Pro Moto Billet sent their spark arrestor end cap for us to install. Here is a walk through of the process.
In total it takes about 30 minutes to do. It requires removing the muffler, the stock end cap, drilling bolt holes for the PMB insert and installing the self tapping screws.
There are some performance changes to our 350 as a result of this. The noise level has gone up a noticeable amount. It has gone from being almost enduro quiet to sounding more like a regular MX bike. There is also a very unexpected increase in power. The 350 hits much harder off the bottom and seems to rev a bit quicker. It is very obvious on the track, it pulls out of the corners harder and with less clutch work. It is a big difference in soft corners.
So I am not wild about the noise increase, but it is a fair trade off for the performance change. If you ride in an area that is noise sensitive you might want to consider the adding the PMB quiet insert. This is what I plan to do.
New Spark Arrestor Insert Use a T25 Torx to remove the stock end cap bolts Hold the muffler under one arm and use rubber mallet to top end cap off Are Austrian girls donating hair for muffler packing? The stock end cap actually contains a screen, it clearly is too large to be a legal spark arrestor, but might pass a stick test. Use a hacksaw to cut the packing near flush to the cannister, scissors to trip around outside edge Install new end cap, PMB recommends loosening screws on opposite end to allow stock core to align with new end cap Use 13/64ths bit to drill new holes. (not included) Light grease on new self tapping screws. I installed carefully with impact driver Install screen and cap I like to use RTV on these screws to prevent seizing due to heat Install back on bike. The muffler did not want to come off the bike easy, so I found it best to remove the side plate.