27
35% Extra 300 ARF Assembly Manual
11. Recommended header length for MTW RE2 tuned
pipe and DA120 is 11 1/2 inches . Assemble the pipe/header
using a vice-grip. Open the clamps and slide them over the
header.
12. Coupler fit on the header is tight. Use the working
bench to lay one side of the coupler on and exert pressure
from the other side by hand.
13. Push the other side of coupler into the RE2 pipe and
leave 1/8–1/4 inch gap between header and pipe.
14. Once satisfied with the gap, pull the clamps on and
over the coupler and pipe. Then slide the other clamp on
the pipe and header, such that is it forward the bump on the
header.
15. Once everything is assembled, heat the couplers
where clamps are using a heat gun at high setting. Do this
for a few minutes and allow some time for cooling. Repeat
this one more time. This creates a good grip and reduces
chance of pipe/header slipping out in flight. It is also
recommended to do this before the first flight. Let engine
idle for 3 to 4 minutes to warm up the couplers, gradually
increasing the throttle to half to get the engine hot and then
allow a cool- down period before the first flight. This should
not need repeating and when done right, header/pipe will not
slip out.
16. Slide the pipes into the tunnel. Use lubricants over
the pipes or the silicone mount for ease of installation.
17. Apply threadlock to header bolts and use DA gasket
or high-temperature RTV and bolt the headers to the engine.
