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-   -   O2 sensor and tune advice (https://www.harley-davidsonforums.com/forums/performance/365645-o2-sensor-tune-advice.html)

Didoman 07-31-2019 10:53 AM

O2 sensor and tune advice
New 2019 Street Bob, about 3 months old. At 1500 miles had some upgrades done: Vance&Hines big radius, Harley heavy breather, Harley pro street tuner, and stage 2 torque kit. All the work was done by the dealer. They used a map for stage 2, though it's probably not tuned right for the short pipes...

Sounds great when you fire it up, engine idles OK, runs smooth. I can ride for ~20 miles before I get a check engine light (seems to pop up in 2nd-3rd gear, noticed it once while engine braking). While light is on the performance drops and it starts backfiring on decel. Codes come back O2 sensors, front and back. I can reset them, then this repeats -- rides smooth for a while then O2 sensor codes.

So I'm pretty sure it's a bad tune / too lean, but I'd love to hear opinions. My big question is what to do... this is the first bike I've bought new and I'd like to keep it in warranty! Right now they are recommending a dyno (and the tune would sure be nice), but I'm concerned there won't be enough headroom with the Harley tuner to deal with the O2 sensor issue. Plus it would be out of pocket. Should I give it a shot or suck it up and go back to stock pipes on their dime?

Advice appreciated!

naknekpete 07-31-2019 11:43 AM

Sounds like you already know the answers as defined by your desire to keep it within warranty. Its possible a a dyno tune on the pro street tuner will help solve your problem, or at least help you decide whether you can run those pipes or not under those limitations. If not and you have to go back to stock exhaust, you will probably need another dyno tune or to run the canned map so its an expensive attempt. They should experiment at their own cost to see if the stuff they sold you will work together, not yours.

Didoman 07-31-2019 05:47 PM

Yeah at the end of the day it just seems a shame to waste the warranty, a few years down the road will be another story. Thanks for the advice, I'll make it clear that if it doesn't work out then redoing exhaust and dyno is gonna be at their cost. Somehow I see that not going over well haha... I'll post back, thanks again

OZman 08-01-2019 09:23 AM

Its under warranty take it back and have them fix it.

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Hillsidecycleco 08-05-2019 06:07 AM

Yes, I agree to get it back to your dealer and have them attend to it.

Didoman 08-06-2019 07:34 AM

Thanks for the advice everyone, it's being run today. Hopefully they can sort it!

naknekpete 08-06-2019 11:42 AM


Originally Posted by Didoman (Post 7300017)
Thanks for the advice everyone, it's being run today. Hopefully they can sort it!

I hope you post back with details. It would be good to know how it works out & if the moco tuner will allow enough AFR change to accommodate the cam & exhaust change combo. I'm kinda curious as to whether it will even handle just the cam change with stock exhaust if you end up having to back to that.

Didoman 08-13-2019 07:28 AM

Update: They ran the dyno and bike was running great, smooth throttle through all gears. Did ~160 miles this weekend, no issues. Monday morning though, check engine popped back on. I'm not sure if it's an O2 code but I assume so, the trigger was the same (slowing down to 20-30 through a toll station, engine breaking in 2nd-3rd gear). Bringing it back in on Thursday, I can't really think of anything else to try but going back to stock exhaust. For now I'll keep the stage 2 and intake, I do prefer it over stock (looks and knee clearance).


OZman 08-13-2019 08:23 AM

With your set up theres no reason why they cant get it to run right with a good dyno tune.

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Didoman 08-13-2019 08:33 AM

Are you thinking they just don't know what they're doing? I'm not very familiar with the Harley tuner, but my understanding is that the software doesn't give you much flexibility in AFRs due to emissions restrictions. Like I'm not sure whether you can just dial down low/mid-rpm enleanment? I should just buy the damn cable and see for myself, they really should include the cable with the tuner.

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