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Thread: Supertrapp Megaphone 1997 Backfire / Pop issue

  1. #1
    Join Date
    Feb 2015
    Location
    Canada
    Posts
    1

    Question Supertrapp Megaphone 1997 Backfire / Pop issue

    Hello All,

    I’m new to the forum and have had an ongoing issue with my 1997 V-Max which “I think” could be related to my installed Supertrapp Megaphone series slip-on exhaust system.

    When I first got the bike several years back, the supertrapps where already installed and the bike worked fine for the first few years… no issues.

    All of a sudden, about three years back, the bike would start cutting out just a little between 5200 – 5500 rpm, right before V-boost would kick in. operation above or below that rpm range was OK. So… I brought my bike to a friend of a friend mechanic and he told me that there were different sized jets in the carb with could be the cause, so.. “we” decided to rejet the carbs to larger jets and all the same size (larger as in, not stock size). Now, my gas mileage when down (no big deal), and the cutting out disappeared (ya!), but a new problem was introduced. Now, when coasting along, not giving or taking away throttle, it backfires or pops; same thing when decelerating. After a year of that, I said, screw this and brought it to a local Yamaha dealer. They told me that the jets that were installed are not correct along with the typical “that’s what you get for using a backyard mechanic attitude”, and installed factory spec jets. Well the problem didn’t go away, and I’m still living with it. I brought it back to that Yamaha dealer, but they seem unwilling to help if I’m not willing to shell out $$$$$ I don’t have…

    My supertrapps have 6 discs installed, factory jets and no modifications to the air box.

    The carbs have been sync’d at Yamaha at the time of the factory jet install “im assuming” and once more after that. No difference.

    I have another person I know that I’m going to visiting in spring who has a v-max and sync’s his own carbs, just to try it again.

    My question is…

    Could this be a supertrapp exhaust problem? And if so, are there any detailed instructions on the modifications that are required to them to work as intended?

    Please understand, I’m not hacking on suppertrapp, love the exhaust. I just want a nice running bike and mechanical support where I live seems a little flakey…

    Any advice would be appreciated.

    Cheers,
    Geary.

  2. #2
    Join Date
    Jul 2007
    Posts
    408

    Default

    Geary,
    Sorry to hear about the issues you are having, however, you do answer your own question;

    When I first got the bike several years back, the supertrapps where already installed and the bike worked fine for the first few years… no issues.

    The bike worked fine, nothing changes then all of a sudden you experience this issue, 'cutting out'. This is either an ignition issue, V-Max's are prone to ignition issues?? or dirt/debris in the fuel?
    The only thing with the exhaust that can wear, would be packing. And old packing would not cause the issues you are having.
    Most likely however, when you 'changed jetting' you probably also cleaned everything? It very well could have been dirt/debris in the carbs causing this 'cutting out'. You took them apart, cleaned? Changed jets? Whatever was in the carb(s) is now gone?? Did you change the fuel filter? I would suggest doing that also-especially on an older bike with ?? miles on it? Just a thought.
    Thanks and good luck with it.

    Jeff
    SuperTrapp

    Quote Originally Posted by 97Max View Post
    Hello All,

    I’m new to the forum and have had an ongoing issue with my 1997 V-Max which “I think” could be related to my installed Supertrapp Megaphone series slip-on exhaust system.

    When I first got the bike several years back, the supertrapps where already installed and the bike worked fine for the first few years… no issues.

    All of a sudden, about three years back, the bike would start cutting out just a little between 5200 – 5500 rpm, right before V-boost would kick in. operation above or below that rpm range was OK. So… I brought my bike to a friend of a friend mechanic and he told me that there were different sized jets in the carb with could be the cause, so.. “we” decided to rejet the carbs to larger jets and all the same size (larger as in, not stock size). Now, my gas mileage when down (no big deal), and the cutting out disappeared (ya!), but a new problem was introduced. Now, when coasting along, not giving or taking away throttle, it backfires or pops; same thing when decelerating. After a year of that, I said, screw this and brought it to a local Yamaha dealer. They told me that the jets that were installed are not correct along with the typical “that’s what you get for using a backyard mechanic attitude”, and installed factory spec jets. Well the problem didn’t go away, and I’m still living with it. I brought it back to that Yamaha dealer, but they seem unwilling to help if I’m not willing to shell out $$$$$ I don’t have…

    My supertrapps have 6 discs installed, factory jets and no modifications to the air box.

    The carbs have been sync’d at Yamaha at the time of the factory jet install “im assuming” and once more after that. No difference.

    I have another person I know that I’m going to visiting in spring who has a v-max and sync’s his own carbs, just to try it again.

    My question is…

    Could this be a supertrapp exhaust problem? And if so, are there any detailed instructions on the modifications that are required to them to work as intended?

    Please understand, I’m not hacking on suppertrapp, love the exhaust. I just want a nice running bike and mechanical support where I live seems a little flakey…

    Any advice would be appreciated.

    Cheers,
    Geary.

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