Specifically interesting.. the 09 YZ450F shorty. i removed the stock end cap and baffles and replaced it with a PMB end cap spark arrestor with quiet core and ultra quiet tip
used a 29MM socket and a sledge to get the motor side baffle out
The sound is about the same in volume as stock, but a bit raspier I guess you could say. Still should pass 96db.
Power is much better than stock.
Yes I know... WR450... my friends ride YZ450s, thought I would share the knowledge with you guys since there wasn't much I could find before this
Now time for the stock tip mods
the stock tip has these wierd restrictor things.. I rammed out the motor side, and cut the tip off and put it on the other side for less resistance. Probably about the same resistance to airflow as a spark arrestor and should still pass the stick test
I think i like the look of the stock tip a bit better..
back in she goes
Sound?? about the same in volume as the PMB, although a bit deeper sound. Performance is still light years ahead of stock, about on par with PMB. Not quite as good as the 07 YZ450F pipe, but nice and short for nasty bootleg trails to stay out of harms way. I am tempted to cut off the swiss cheese cone restrictor baffle altogether for a straight shot out the pipe.. but then I would need a spark arrestor (ghetto booty-fabbed one onto my 07 YZ450 pipe)
So for on the cheap (free), you can mod the 09 Pipe for much better power over stock. I think the motor side baffle really hampers performance.
If you want some bling, get the PMB end cap and have a legal spark arrestor too
07 YZ450F pipe with White Bros spark arrestor jammed in
Edited by n16ht5, June 17, 2012 - 11:19 PM.