Originally Posted by Ed@Ford
Yes, compared to this CRF spark arrestor, the "windows" that are covered with screen in the XR400R spark arrestor are HUGE by comparison. BUT, there is also a snuffer in the end of the XR400 spark arrestor that keeps the noise down to 86dB..I think. If you take that snuffer out, it is VERY noisy...way over he 96dB allowed in offroad events now by AMA. I created a snuffer with much less restriction similar to the ones created way back then by XR's only. By comparison, the CRF has fairly small windows...but no snuffer. My thought is to take a stock CRF spark arrestor, or a reasonable copy, and hog out bigger windows, add screen, and get to a reasonable sound level, with a reasonable power increase. I am personally not interested in spending $700 to remove 7 pounds, and end up with a nasty loud muffler...and yes....anything over 90dB is LOUD in my book...but the stock CRF is 80dB....is similarly over kill in the opposite direction. I have a sound meter, and plan on taking some dimensions off the stock XR400 "windows" and the CFR "windows" over the next couple weeks.
80 dB, had no idea, seems pretty quiet, even by comparing to bikes I've had recently. I think some have said that this computer controlled system is way more sophisticated than ones in the past, mostly to keep the "backyard mechanic", out of the loop. Haven't heard from Ramz lately, I think he stated something like, you won't believe what information we can get out of this. Not quoting, but here on this thread, quite early on, he stated something similar. Others have noted that changing anything is a no no on current laws, nobody getting hung around here just lately, though, the pirates are taking mufflers off for the first mod. Oh crap, pirates, and KTM bashing, I though this was a CRF forum