FYI: I have started communications with Mark Mitchell, John Goodpaster and David Lamberth to look at vintage racing exhaust decibals where a common standard and testing would be established. I did a little testing at Putnam Park this past weekend. I was along the straight about 100 yards from the final corner about 10 feet from the bikes. The modern 600s with a pipe were in the 102 to 105 range with a couple at 106 or 107. Roger tested my CB350 at 108 and while racing with another bike (combination at 110). I haven't re-packed the can in a while, therefore need to re-pack and test. I am going to do a lot of testing at Grattan in a variety of situations. Although the tests listed in the rules are different from what I used, the full throttle out of a turn seems to be the most realistic. More to follow. Jim
Some other bikes I tested also during the V1 race. The 2 RDs racing for first were 105, the #1 single was 106, the 400 4 Honda was 100 and Bill Moeller was 105. Roger
Jim: I noticed your letter in Vintage Views also and hope they take notice. Personally, I use unmodified, stock pipes on both race bikes and so have made the committment to be as quiet as possible (no, it's not because I'm cheap). Seems to me that there are only a few bikes that are a real problem. Some are downright obnoxious to me and so must really be bad for a non-biker resident living nearby. It is also obvious that if everybody is actually required to be less noisy, quiet mufflers are no disadvantage. What can I do to help push this?
Oldbackmarker: In general the four-strokes sound great and for the most part are not excessive, therefore it was not considered an issue. In the last couple of years with new tracks being built the noise issue is not becoming a problem. Now that this has been identified as an issue people are taking action like you to make sure their bikes are at an appropriate level. As I stated, I didn't realize my bike was at 108 until I purchased a meter to check. Now I need to fix it.... It appears everyone is working towards solving this issue which is great and racing at tracks because of noise will be a non-issue. My goal now is too see if Wera Vintage and AHRMA can come up with a 'good' standard for both organizations including a testing procedure. Right now for each vintage racer to test their bike and determine the best type of silencing method for the exhaust if required. I believe the Wera rule is a bike must past an "on track" and stationary test not more than 105dBA. Thanks for the interest
"The 2 RDs racing for first were 105".....Hey I was one of those RD guys.........That noise level must have occured where I was missing that shift and overreving the motor coming on to the front straight...Yeah that's it....And I thought you guys were just hanging out watching our exciting race. I should have known. Thanks for the info.
Did you happen to get any readings on the GS450 with the dual high pipes? I had them modified to try to take some of the bark out before I started doing more Wera vintage. Still loud but not near as bad as they were before the mods. Bob
Bob: Sorry, we didn't. Had just got the sound meter and was doing some brief testing getting ready for the upcoming AHRMA events. I plan to be at the next Wera Vintage at Putnam and could check then.
Evil, You must have missed a gear each lap! I was enjoying the good race. I received the highest reading when the meter was aimed 30-45 degrees down the track. I tried 90 degrees and as straight down the track as possible, both gave a lower reading. I was standing at the guard rail next to the track. Roger
