problems with THUNDER- MAX

Discussion in 'Engine, Fuel and Exhaust' started by river rat, Sep 12, 2009.

  1. river rat

    river rat Member

    I am about to rip my hair out!
    I have a 2007 Softail Springer classic, the bike is stock except for HD Stage one air intake, and Rinehart Eagle Beak Slip ons.
    I purchased a Thunder Max with Auto tune, because it appeared to be slightly better than the SERT which I have on my other bike Road King custom. Put the Road King on a DYNO after similar mods.
    I installed the T MAX on my soft tall, and I have consistent decal popping (loud Cracks) and it just doesn’t seem to be right, back fires through the intake after sitting at a stop light. I have cleared the Learned Adjustments four times and also re initialize it each time. The last time I put about 350 miles on it then sent the MAP to Zippers. They contacted me and told me everything was fine and appeared to be working ok. After some additionally discussion we identified that my battery may be the problem, The technician stated that when starting if the voltage drops between 8 and 10 volts is wipes out the initiation. Well my battery was dropping to 9.5- 10 volts. So I put a new one in cleared everything and re initialized and went for a ride, no change.
    It appears that I am going to have take it to a dealer that Zippers provided, to get a dyno.
    I am open for suggestions, there are no exhaust leaks and no intake air leaks and according to fuel moto and zipper the correct map is installed. The bike has a little over 1k on it. Its my weekend bike
  2. MHenriques

    MHenriques Member

  3. biscuit

    biscuit Junior Member


    Have you tried enabling the 'Decel fuel cut-off' and the 'Decel Fuel Cut RPM'?These features are in the Basic Settings and are meant to reduce exhaust popping on deceleration by richening the fuel mixture.
    Just a thought.
  4. river rat

    river rat Member

    Yes I have enabled the decal and adjusted the rpm range, Thanks if you have any other suggestions throw them my way

    Thanks for the link, the portion in regards to adjusting the timing appears is quite intresting
    Last edited by a moderator: Sep 13, 2009
  5. eleft36

    eleft36 Junior Member

    If this the results from the install, initialization and running the auto IAC function.
    Recheck your complete install and connections to the ECM harness, check all other electrical connections including grounds.

    My '07 FXSTC Thunder Max A/T is flawless from install 5,800 miles ago


  6. river rat

    river rat Member

    I spoke to a different tech rep at Zippers today. After all of my frustration I believe he may have provided the resolution to the problem. I should know within the next few days.
    My Softail Springer Classic has a cross over exhaust pipe (stock). I added Reinhart Eagle beak mufflers which have little to no resistance for back pressure; which allows air to be sucked back through the left exhaust during decal which creates decal popping. After explain my set up to the Tech rep it appeared he knew right away what the problem was and recommended a device called a Pop Stopper a device that is inserted in to the exhaust pipe between the pipe and the muffler. This device creates back pressure on the left exhaust pipe to prevent the back flow of air during decal. In addition the tech rep mentioned that after the device has been inserted it is highly probable that the decal fuel cut may not be required. However if it is required once enabled change the High fuel cut to 2272 rpm and the low fuel cut to 1792 rpm.
    The pop stopper cost $5.00 and shipping about 4 to 5 dollars. I will install the device and conduct a test. Then comment on how things work out, just in case someone else has the same problem.
  7. glider

    glider Veteran Member

    Be curious to see what difference it makes and how the sound is after the installation.
  8. Bud White

    Bud White Well-Known Member Retired Moderators

    Im interested also to see how it works
  9. river rat

    river rat Member

    My POP STOPPER arrived today $13.00 total cost of the stopper and shipping (shipping was $9.00). It took approximately 20 minutes to install.
    As for the ECM (Thunder –Max) prior to installing the Pop Stopper I cleared all the learned fuel adjustments and idle control adjustments (IAC) and re initiated the ECM. Then I proceeded to install the Pop Stopper. After installation I started the bike and ran the auto (IAC) also I enabled the decal fuel cut and changed the default setting to High fuel cut to 2272 rpm and the low fuel cut to 1792 rpm which is what was recommended by Zippers tech rep.
    I don’t think that I needed to clear all the adjustments however I wanted to start fresh. Next I took the bike out for a 50 mile ride. Wow what a difference, the bike runs fantastic, the difference is night and day with no decal popping.
    I feel it prudent to mention that the left side exhaust the side installed the pop stopper on in; exhaust flow has been drastically reduced to the point the muffler does not get hot only warm. I could hold my hand on it after riding 50 miles. I also noticed a fair amount of condensation dripping out near the end cap bolt only on the left side. My concern is the muffler will not get hot enough to get rid on the condensate which will lead to internal rust.
    As for the sound it still sounds good, but different, the decreased flow on the left side has changed the rumble to where it sounds like a 2 into 1.
    Over all I am happy however in the future I my change the exhaust to True duals. I really didn’t realize the cross over pipe would have such an effect with free flowing mufflers. I plan on putting a couple hundred miles on this bike during the weekend. So far I am really pleased with how the THUNDER MAX is working significant change/improvements in 50 miles and should continue to tune as I ride.
    I have added some pictures of the pop stopper, not to insult anyone but the device (pop stopper) is new to me

    Attached Files:

    Last edited by a moderator: Sep 17, 2009
  10. glider

    glider Veteran Member

    Looks like the solution was found by Zippers.

    I think I would have notched the popper stopper at the 6 oclock position to pass any condensation build up in the pipe and maybe enlarge the hole a tad so the muffler can heat a bit more to eliminate any condensate in there.