I keep learning something new almost every week and try to share it with you guys out there. I surely enjoy reading about your discoveries and adventures. I have a 04 Foreman 4x4s model. It has a bigfoot kit with 26 inch tires. It didnt have the power I thought it should have so I installed a performance kit with the hmf pipe, jet and needle kit, and k&n air filter and sock. At my elevation the kit called for a smaller main jet size than what came in the atv from the factory, so I followed instuctions to the letter. It had more grunt that originally , but not what I expected. Top end is flat and around 42mph on a flat paved road. Real slow. I also bought the silencer tube with the kit because I dont want it to be too noisey. When riding today we heard a super loud something coming through the woods toward us. IT turned out to be a guy on a new Rincon with the same kit I have on mine and the hmf pipe with no silencer installed. He noticed I had the same kit with the silencer and asked if I had ever ridden with the silencer removed. I said no. He said it makes all the difference in the world. I had my allen wrench in the tool kit so I quickly removed it to see if it did make a differnce. Man I hate the loud noise, but the power increase was unbelievable. It fishtails in fourth gear now when you nail it. The torque on the hill and mudholes was incredible, like a whole different machine. Apparantly these kits are designed to run without the silencer. Does anyone know of a less restrictive silencer or any mods I may do to this one to find a happy medium between the noise and power? I am really impressed with the power difference. We hit the same paved road again going from one powerline to another and this time at 45 mph it still had lots to go..feels like a bigbore kit or something. Before my plug was really black like it was too rich with the smaller jet. When I removed the silencer, the muffler was full of sut really bad. Now the plug reads normal with a brown color.

 

Try gutting the silencer and repack. leave out the quitcore if posible.

 

All there is to the silencer is its a 1 inch diameter pipe about 6 inches long with a screen wire cone shape on the end that sticks out of the muffler. I have thought about either cutting the pipe off shorter or drilling out the screen wire to a larger size. It has no packing on it like a conventional type baffle.