Wide open throttle dies out

• carb
• performance tuning

• WT

  Walter Todt

  8/29/25, 10:45 AM

  Honda shadow vt600 dual carb, velocity stacks performance kit installed with biggest pilot and main jets. At wide open throttle it cuts out, 2.5 turns out on both carbs. Thoughts on if I need to locate a bigger main jet? Also backfires on decel. Seems odd if I'm running the biggest jets. Any help would be appreciated

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  TJ Admin Staff member

  8/29/25, 11:53 AM

  @Walter Todt first, youll want to review this documentation - it will help you un derstand what to adjust - https://shoptjbc.com/community/brutalforums/topic/176621/tuning-your-carbureted-honda-shadow-everything-you-need-to-know

  seriously. read that shit. dont just skip over it. doing so will save you a ton of time and money in the long run. 

  A couple things could be happening:
  you could have too much positive pressure on the float bowls, not allowing the bolws to fill quick enough., this is easy to fix, just run about 6-10 inches of line from the float bowl vents towards the rear of the bike. 
  Decel pop is unburnt fuel igniting in the exhaust or you have an exhaust leak. 
  you could have weak spark. it could be the plugs are dirty, not properly gapped, faulty resistor caps, bad ignition wires, coils going out. bigger main will likely not solve your problem. check the color of your spark plugs and go from there. 
  
  

  DO FUN SHIT!
  Check the FAQ's here for tons of tuning info and more!! - t.ly/MA6r6

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