• Hi everyone,

    As you all know, Coffee (Dean) passed away a couple of years ago. I am Dean's ex-wife's husband and happen to have spent my career in tech. Over the years, I occasionally helped Dean with various tech issues.

    When he passed, I worked with his kids to gather the necessary credentials to keep this site running. Since then (and for however long they worked with Coffee), Woodschick and Dirtdame have been maintaining the site and covering the costs. Without their hard work and financial support, CafeHusky would have been lost.

    Over the past couple of weeks, I’ve been working to migrate the site to a free cloud compute instance so that Woodschick and Dirtdame no longer have to fund it. At the same time, I’ve updated the site to a current version of XenForo (the discussion software it runs on). The previous version was outdated and no longer supported.

    Unfortunately, the new software version doesn’t support importing the old site’s styles, so for now, you’ll see the XenForo default style. This may change over time.

    Coffee didn’t document the work he did on the site, so I’ve been digging through the old setup to understand how everything was running. There may still be things I’ve missed. One known issue is that email functionality is not yet working on the new site, but I hope to resolve this over time.

    Thanks for your patience and support!

Bike runs poorly with spark arrestor

Guoseph

Guoseph

Husqvarna
AA Class
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.
 
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.

.
 
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.
 
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?
 
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
 
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.
 
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.
 
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?
 
Fast1 said:
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?
Click to expand...


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:

15288472122_d75dc67120_z.jpg


15285721281_dcf196b7c8_z.jpg


15288465182_bb455f1ca9_z.jpg


15102294247_dc024be3e6_z.jpg
 
Sorry I didn't answer your question directly. Yes the stumble/surge was a known issue at the time of purchase.
 
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.

 
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.
 
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.
 
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?
 
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