staintune-08 headpipe-sparky report.
Posted: Wed Apr 30, 2008 11:52 pm
I put a staintune-o8headpipe on my 05 with a 2-1/8 " sparky USFS
approved spark arrestor. It really helped with the power output and
the gas mileage has increased from 33 mpg to about 40 mpg. They are
a bolt on application, except the sparky which requires a 2" ID x 2-
1/8" OD adaptor ring. There is a massive increase in power in the
2k to 4k range. This has the 685 kit and prior to the new pipe
torque was up but not power or gas mileage. It will spin a new D606
on hard packed clay when rolling on from 2k RPM around 3-3.5K RPM.
It accelerates hard now in all gears, there is less vibration and
several times I found I was a gear lower at the same speed/rpm
comfort level than before this mod. Like having a 6 speed instead
of 5. 15/47 gearing. Between the 685 kit and the new pipe/header
vibration is a non issue now. The noise level with the insert in is
91 decibles. I added fine stainless steel wool to buffer it. A
little burned thru, a lot reduces the power output significantly and
is probably also burning away. Increasing exhaust flow seems to be
the main contributor to power increase. Also replaced my carb
diaphram with one sourced from HD. It is about 3 times more
flexable. The amount of throttle opening has changed from 2/3 down
to 1/3 at normal rpm and response it better. I think the pipe is
the real change in performance. Tom