[cherrybomb]

Heard a rattle during a ride yesterday, I had taken my ear plugs out for the last 30 miles of a 200 mile run. Thought it was a heat shield so off I went home. A quick inspection at home revealed that both exhaust nuts back off the studs on the rear cylinder flange. The rattle was the exhaust collar completely free of the studs.

The bike did not seem to run badly and the exhaust note was a tad different. No back firing or decel pop.

Checked diagnostics and PO151 came up and I cleared it. Reinstalled nuts that fell off and all is good.

I would have expected the bike to have run badly if the rear O2 sensor was reading excess O2 in the exhaust. Any harm done as I suspect the ECM was dumping fuel into the rear cylinder to try to correct a lean condition ?

 

[Chopperjohn]

I would think that no O2 would enter the pipe only that some exhaust gasses would get out of the pipe.

 

[Jekkhar]

That's exactly how the studs broke off of the heads on my air cooked Harley.

Its a good idea to re-tighten them after a few heat cycles.

Sent from my LG-H811 using Tapatalk

 

[RustyG]

That happens if you tighten those nuts to factory torque specs. You need to put a little more wrench on them than HD's recommendation.

 

[cherrybomb]

That happens if you tighten those nuts to factory torque specs. You need to put a little more wrench on them than HD's recommendation.

Torque 100-120 inch pounds?

 

[cherrybomb]

I would think that no O2 would enter the pipe only that some exhaust gasses would get out of the pipe.

The exhaust gasses are pulsing all the time, air will be drawn in to the leak and will pass the O2 sensor.
Goggle PO151, it's a universal can bus code.

 

[rbabos]

The exhaust gasses are pulsing all the time, air will be drawn in to the leak and will pass the O2 sensor.
Goggle PO151, it's a universal can bus code.

Yes, air will be drawn in but you don't have CanBus. The code is the same for J1850
Ron