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Thread: First time on the dragstrip!

  1. #31
    Join Date
    Jun 2018
    Location
    Stuck in Lodi, again
    Posts
    113

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    patrino, what is the db limit where you race? I have done some vintage bike racing & was allowed (aloud!) 100 db due to class rules while "modern" bikes were limited to 93 or some such thing. Keep it up & good luck!

  2. #32
    Join Date
    Dec 2019
    Location
    Portland, Oregon
    Posts
    78

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    My 'home track' is Portland International Raceway. It's only ~15 minutes from my house, and is actually a city park. Hard to get more convenient! The noise limit for the night drags is 103 dB. I got popped at 106 dB on the 131 mph pass. We dug into my spares, looking for a way to quiet it down on the spot, so we wouldn't have to quit. We wound up rotating the 'muffler' 90 degrees, so that it pointed down towards the ground (thinking that it might take some of the energy out of the exhaust). That got us down to 105 dB!

    Heading up to the shop this afternoon to take some measurements & inspections, see what I can work out. I'll keep folks posted!

  3. #33
    Join Date
    Dec 2019
    Location
    Portland, Oregon
    Posts
    78

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    Photos up soon ... I fit a baffled muffler last week. It worked great, and I ran last night without any problems. Best pass was a 10.392 @ 132 mph.

  4. #34
    Join Date
    Dec 2019
    Location
    Portland, Oregon
    Posts
    78

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    One of the many interesting things is that my top speed last Friday was only a mile or two per hour faster than my former previous top speed, but my ET was down by ~0.4 seconds. The main difference between my best runs and my former best runs were better 60' times. I've heard that a tenth quicker in a 60' time means three to four tenths quicker on the quarter ... wasn't sure if that was B.S. or not but my time slips suggest that's the case.

    A friend who has come out to the track multiple times is good with a TIG. If he's willing, I'll ask him to add some mounting points on the frame and swingarm, to fit some additional struts, to stiffen the rear end. I'm running a strut now, but with the long swingarm and stackup in slop of various bushings and fasteners, there's still a noteable amount of flex in the rear of the bike. I know that stiffer isn't always better when it comes to motorcycle racing, but it's not too much work (figure a half day to make and weld the brackets, and a half day to fashion some additional struts) and can be undone pretty easily if it doesn't help (just undo the new struts).

  5. #35
    Join Date
    May 2012
    Location
    Youngstown,Ohio
    Posts
    3,625

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    10.32 @ 132 is pretty respectable👍 Maybe have your buddy weld you up a set of wheelie bars. That would help with your consistancy and put you deep into the 10's. Keep up the good work and thanks for keeping us posted.
    My Motorcycles:
    21 Triumph Tiger 900 GT (coming to a town near you)
    16 Yamaha FJR1300 (Probably been to a town near you)
    82 1100e Drag Bike (needs race engine)
    81 1100e Street Bike (with race engine)
    79 1000e (all original)
    82 850g (all original)
    82 750e (parts Bike)
    80 KZ650f (needs restored)

  6. #36
    Join Date
    Dec 2019
    Location
    Portland, Oregon
    Posts
    78

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    Here are some exhaust photos. Not pretty or light, but it did the job.

    IMG_0361.jpg

  7. #37
    Join Date
    Dec 2019
    Location
    Portland, Oregon
    Posts
    78

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    Another one:

    IMG_0362.jpg

  8. #38
    Join Date
    Dec 2019
    Location
    Portland, Oregon
    Posts
    78

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    And a final one. The second hanger bracket was necessary, due to the flex of the first hanger bracket (it's pretty long) and the flex at the header-to-muffler joint (it's flex pipe). One bracket would've almost certainly work but I felt better without the pipe wobbling with only a single bracket.

    IMG_0363.jpg

  9. #39
    Join Date
    Jun 2013
    Location
    Enumclaw, WA
    Posts
    2,461

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    Last time I was at PIR they ran 1/8 mile. Weekly brackets are 1/4 now?

    09 Kaw C14 Rocket powered Barcalounger
    1983 GS1100e
    82\83 1100e Frankenbike
    1980 GS1260
    Previous 65 Suzuki 80 Scrambler, 76 KZ900, 02 GSF1200S, 81 GS1100e, 80 GS850G

  10. #40
    Join Date
    Dec 2019
    Location
    Portland, Oregon
    Posts
    78

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    @bobgroger, I've only run there three times, always on a Friday or Saturday night, and it has always been 1/4-mile. I believe the bracket racing's run on Wednesdays over the 1/8 mile.

    I've been only going to the quarters because I've been focusing on getting the bike and myself dialed in. It's easier for me to do both of those, without at the same time trying to compete against someone. That said, I finally feel like I've got the bike (and me) set up OK, so planning to hit a Wednesday night soon!

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