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View Full Version : Installing DG RCM Exhaust


cavebankraider
11-07-2009, 11:20 AM
I recently bought a DG exhaust system for a 1979 ATC 110. Can anyone give me some insight on installing this. It does not seem to fit in the stock location. Am I missing something?
dirt_19
11-08-2009, 12:22 AM
um i dont have a atc 110 but i believe the dg exhaust runs along the out side of the frame in stead of down the center of the frame like i think the stock 110 exhaust does
Mr_RPM
07-31-2010, 04:02 PM
yep it runs out the side above the brake lever and out by the axle, i just bought one myself. it came with the worst instructions ever and find it funny. otherwise seems like a solid exhaust. not super impressed with the finish (ill be painting it as soonn as the OEM paint burns off) and doesn't seem to be super high flow, but most machines need that back pressure so i can understand that.
It came with a bracket that i have no clue where it goes since i haven't tried it yet and the instructions don't show.
im a little confused with the design, it opens up towards the end like a megaphone then gets real small last second with a muffler type pipe (pipe with holes that has packing behind the holes)
im not sure why it would open up real big like it does then just shoves all the air back into a small hole. maybe someone will know why?
Mr_RPM
07-31-2010, 08:20 PM
this is what i found on the RCM exhaust (reverse megaphone exhaust): "Here's a rough explaination. They work in the same way that an expansion chamber works on a two stroke. In a four stroke racing engine there is a lot of over-lap in the valves. In other words, both intake and exhaust valves are open at the same time at some point during the stroke.

The reverse on the megaphone sends a pulse back to the beginning of the pipe or exhaust port inorder to help hold the charge in the cylinder during this over-lap period. The idea is for the pulse to meet the charge at the exact moment of over-lap while the charge is trying to escape the combustion chamber.

If everything is tuned correctly, this pulse keeps more of the charge in the combustion chamber. Therefore, more HP."