Bike runs poorly with spark arrestor

Discussion in '610/630' started by Guoseph, Sep 3, 2014.

  1. Guoseph Husqvarna
    AA Class

    Location:
    Alameda, CA
    Husqvarna Motorcycle:
    FE501S
    Other Motorcycles:
    Honda VFR800, KTM 525 EXC
    Hi Everyone,

    Been chasing this issue for a while now and can't seem to get it right. The basic issue is that the bike has a mid-range (3500-5000) stumble with the spark arrestor installed, and no amount of fiddling with the JD tuner (with my admitted lack of expertise in tuning and poorly calibrated butt dyno) has rid me of this stumble. The bike runs very well and is smooth throughout the rev range without the spark arrestor installed.

    Here's the bike configuration:

    P/U
    Arrow ECU (iBeat settings unknown)
    FMF Midpipe and Exhaust (Model unknown, please let me know if there's a way to identify via external markings or shape)
    Airbox snorkel and maze removed
    JD Jetting Tuner (Problem existed before I installed the JD, have been trying to get the JD to compensate for whatever the Arrow ECU is doing)

    Here's what I've tried:

    Various setting combinations of Green/Yellow/Yellow-Blue between 2.0 - 4.0.
    Moving Yellow-Blue seems to move the place where it stumbles up and down the range a bit.
    I've tried Green=Yellow, Green>Yellow, Yellow>Green, but non of them seem to solve the issue.

    With the spark arrestor I assume less air is flowing so it makes sense to take a bike that was tuned for the more open exhaust using iBeat down a notch using a JD, but taking any setting down to 2.0 just makes it feel anemic without solving the problem, and 2.5 doesn't seem to make a difference.

    I have no prior carb tuning experience so the explanations I've read about float and needle and jets are basically greek to me unfortunately.

    I think I have the following things to try and would like your opinion on these or what else I can do.

    1.) Buy an iBeat (Does anyone know if they are compatible with the Arrow ECU?)
    2.) Buy an AF Mixture meter
    3.) Sell the JD and get an PCV + Autotune
    4.) Take it to get a professional dyno tune

    I personally lean toward me buying some thing to add to my collection of gadgets than taking it to someone, even though taking it to someone might yield me better results :D.

    Thanks for reading this long winded thread, if any of you are in the bay area and have a dyno (or good butt dyno) and some carb or efi tuning experience, please let me know if you can give a quick assist.

    Alex
    P.S. The spark arrestor is clean and not clogged up with junk.
  2. speedydave Husqvarna

    Location:
    Hickory, NC
    Husqvarna Motorcycle:
    '08 610 SM
    Other Motorcycles:
    Thruxton
    Can you pull the arrow ecu and just tune with the JD only? That seems like a lot of piggybacking to me.
  3. DYNOBOB Husqvarna
    Pro Class

    Location:
    Cincinnati (Lebanon), OH
    Husqvarna Motorcycle:
    TE630
    Other Motorcycles:
    SuperTenere-GL1800-CBR900RR-KLX250S
    I'm not familiar w/ the Arrow ecu, does it replace the stock ecu or add on? If it's an add-on than I'd get rid of it.

    .
  4. Guoseph Husqvarna
    AA Class

    Location:
    Alameda, CA
    Husqvarna Motorcycle:
    FE501S
    Other Motorcycles:
    Honda VFR800, KTM 525 EXC
    Thanks for the suggestion guys. Unfortunately the Arrow ECU is a total replacement of the stock, if I pulled it I would have no ECU. It is designed to be used in conjunction with the Arrow twin exhaust, but I bought the bike used and this configuration of parts is what came with it. From reading other threads I know the Arrow ECU is a "Race" map and makes the fuel mixture more rich compared to stock and may change the timing a bit, I'm not sure if it does anything else.
  5. Fast1 Husqvarna
    AA Class

    Location:
    Minneapolis, MN
    My gut feeling based on my carb tuning experience would indicate that your fuel metering is rich in the mid range given that removing the sparky resolves the issue. Have you tried going down to the lowest JD setting possible for mid range and trying it?
  6. Guoseph Husqvarna
    AA Class

    Location:
    Alameda, CA
    Husqvarna Motorcycle:
    FE501S
    Other Motorcycles:
    Honda VFR800, KTM 525 EXC
    Hi Mike,

    I've gone down as far as 2 on the JD (3 is what I understand to be "neutral", 1 is lowest, 0.5 increments). At 2 the bike feels a bit less responsive in the midrange (yellow setting) and the sound changes. I have not tried 1.5.

    Alex
  7. JoiseyJanet Husqvarna
    AA Class

    Location:
    New Jersey, USA
    Is it a stumble (stall) or more of a hunting or surging (up and down) in the low rpm range?
    If I recall, someone on this forum mentioned using an Iridium spark plug to improve that condition. I believe it was CR8EIX. Not sure if it will work in your situation, but just a thought.
  8. Guoseph Husqvarna
    AA Class

    Location:
    Alameda, CA
    Husqvarna Motorcycle:
    FE501S
    Other Motorcycles:
    Honda VFR800, KTM 525 EXC
    It may surge a little when I try to hold steady throttle at around 3500 - 4000 rpm, but what's more concerning is that it stumbles sometimes when rolling on the gas in this range. I haven't been able to scientifically reproduce the stumble, it always happens when I least want it to, there's too much puckering going on for me to notice what rpm it stumbled at.
  9. Fast1 Husqvarna
    AA Class

    Location:
    Minneapolis, MN
    Can you provide a photo of the spark arrestor and also a separate photo of the exhaust installed on the bike?

    Has the problem been present since you have owned the bike?
  10. Guoseph Husqvarna
    AA Class

    Location:
    Alameda, CA
    Husqvarna Motorcycle:
    FE501S
    Other Motorcycles:
    Honda VFR800, KTM 525 EXC

    Hi Mike,

    Yes, I bought the bike second hand and it was dealer tuned to run without the spark arrestor. I figured since it ran fine w/o it I'd be able to do some minor tweaking to get it to work w/ the spark arrestor and a JD. Clearly my expectations outpaced my technical ability.

    Anyway, here are the pictures:

    [IMG]

    [IMG]

    [IMG]

    [IMG]
  11. Guoseph Husqvarna
    AA Class

    Location:
    Alameda, CA
    Husqvarna Motorcycle:
    FE501S
    Other Motorcycles:
    Honda VFR800, KTM 525 EXC
    Sorry I didn't answer your question directly. Yes the stumble/surge was a known issue at the time of purchase.
  12. Fast1 Husqvarna
    AA Class

    Location:
    Minneapolis, MN
    For some reason that spark arrestor appears to be a different version than comes with that FMF slip on.

    I believe someone has put in another sparky that is intended for more quiet operation. I don't have a FMF slip on anymore because I sold it with my TE however from the pics it appears different.

    Maybe someone with a FMF can photo theirs. I really believe that is the problem.. That sparky is extremely restrictive,,

    edit
    ok I found a pic.. you got the wrong sparky in there.. see the screen placement on this one and how large of diameter it is?


    Order one from FMF and I think that will solve the problem.

    [IMG]
  13. Guoseph Husqvarna
    AA Class

    Location:
    Alameda, CA
    Husqvarna Motorcycle:
    FE501S
    Other Motorcycles:
    Honda VFR800, KTM 525 EXC
    Yeah I think you are right. I found 4 different versions of "spark arrester" on FMF's web page. I also have two spark arresters for a Leo Vince pipe, one that looks like this and labeled DB killer, the other looks like an overgrown thimble. However, even the more restrictive DB killer for the Leo system didn't change running characteristics.
  14. Fast1 Husqvarna
    AA Class

    Location:
    Minneapolis, MN
    IMO I'd purchase the least restrictive spark arrestor available for that slip-on since you have the arrow ECU. Set the JD tuner at the recommended settings. If possible IBeat the bike and set at 100,100,100 fuel metering. Then attempt to remedy any fueling issues with the JD tuner. Or if you have unlimited access to Ibeat, remove the JD tuner all together and use the Ibeat at 108, 108, 116 to start with and tune from there using Ibeat.
  15. Guoseph Husqvarna
    AA Class

    Location:
    Alameda, CA
    Husqvarna Motorcycle:
    FE501S
    Other Motorcycles:
    Honda VFR800, KTM 525 EXC
    Thanks Mike, sounds like iBeat might be a good investment. Does it work for all Huskies or do you have to get different versions for different bikes?