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Message started by MMRanch on 10/19/16 at 21:18:48

Title: Oxygen Sensor
Post by MMRanch on 10/19/16 at 21:18:48

O K .

Does any one know how an Oxygen Sensor works ?

So the Harley has a diagnostic function in its computer. There is an Oxygen Sensor on both exhaust manifolds . On my way to Oklahoma this summer the motor started running a little ruff. Well , I tried injector cleaners , and different spark plugs. Still runs ruff. Fuel millage is down a little too (48-52 now --- 52-58 before). So , the Diagnostic code thing says the rear Oxygen Sensor is running Rich.

I pulled the rear O Sensor and mounted it loosely in the vice , then heated it (gently) with a propane torch while a Volt meter was hooked to the two wire leads. "Zero" volts cold , I went up to .34 volt testing it with mild heat.

The real question is : If I put a spacer in to back the O Sensor back out of the the exhaust flow a little --- then the sensor will produce less voltage . So should that elevate the running rich problem ?

:-/

Title: Re: Oxygen Sensor
Post by Dave on 10/20/16 at 02:55:18

An oxygen sensor looks for any remaining oxgen in the exhaust stream. Heat is part of the process.....but you can't take the reading from the torch as meaning anything - as the sensor was trying to read the mixture being provided by the torch flame/fumes.

You might try moving the sensors around and see if the rear cylinder is still the problem child - if so.....it is probably an injector that is going bad.

Title: Re: Oxygen Sensor
Post by MMRanch on 10/20/16 at 06:35:09

You know thats not a bad idea ! (switch-en around)

I thought it might be like adjusting the Oxygen/Acetylene torch --- as in the more Oxygen = hotter flame. Being the more Oxygen in the exhaust flow the hotter it is , but I'm only guessing about how those things actually work.

One thing for sure is : the hotter it gets the more voltage it produces . :-?

Title: Re: Oxygen Sensor
Post by MMRanch on 11/03/16 at 19:52:33

Dave you may find this hard to believe :

So I did switch the O2 sensors around ... no effect

I put the adapters in to space the sensors back away from the exhaust flow ... fuel millage went up a little but the roughness was still there.

Next I put a pair of 12" shorties mufflers on it and the roughness disappeared ... and to my surprise its not much louder ??? 8-)
also : The old mufflers and conecting bracket weighed close to 50# and the pair of Shorties weigh less than 5# :) I loss 45# in one day !!! ;D

Title: Re: Oxygen Sensor
Post by verslagen1 on 11/03/16 at 20:00:47

maybe you had the same problem I had.
the muff are burnt out and the half the baffles are clogging up the others.

Title: Re: Oxygen Sensor
Post by MMRanch on 11/03/16 at 20:23:50

I believe your right Versey , at the time the Roughness started I was on the Super-Slab running 75-80 ish for 150 miles strait (4.5 gal.tank), things had to be petty warm inside there ! ;D

You know what ... its not fun riding that fast , but you know how it is when ya got a long distance to cover . :P

Title: Re: Oxygen Sensor
Post by springman on 11/04/16 at 08:36:04

There you go. Textbook example of muffler bearings going bad. 8-)

Title: Re: Oxygen Sensor
Post by Serowbot on 11/04/16 at 09:25:33

Got a pic?... Where did you get the shorties?
I'd really like to lose a few pounds off my Sporty... 8-)

I've also been known to scrape the stock muffies in turns... very scary... :-?

Title: Re: Oxygen Sensor
Post by MMRanch on 11/04/16 at 19:47:23

I'll see if I can hunt up the internal baffles I used , but in short they are the "tune able" ones off ebay .

Mufflers are 1.75" one end / 1.5" other end

Two baffles meet in the middle with a homemade connector pipe and baffles are fastened on each end as designed.

I'll take "more detailed" pictures if ya need them. :)

Effective action for when : Textbook example of muffler bearings going bad ;D

Title: Re: Oxygen Sensor
Post by MMRanch on 11/04/16 at 20:03:52

original mufflers had a connector bracket between mufflers.

Title: Re: Oxygen Sensor
Post by Serowbot on 11/05/16 at 07:46:17

If you could find a link,.. 8-)
I found these, but they don;t look the same...
http://www.ebay.com/itm/HARLEY-SPORTSTER-CHOPPER-CAFE-RACER-TWIN-CHROME-SHORTY-EXHAUST-PIPES-MUFFLERS-/262336711457?hash=item3d147c8b21:g:xbgAAOSwgQ9VsV9U&vxp=mtr
http://i.ebayimg.com/images/g/xbgAAOSwgQ9VsV9U/s-l1600.jpg

Title: Re: Oxygen Sensor
Post by oldNslow on 11/05/16 at 09:38:35

Couple more questions if you don't mind.

Are those one piece pipes all the way from the heads, or are they mufflers on the stock headers ?

How are they supported with the OEM bracket/crossover pipe gone. Just hanging off the end of the header, or is there some kind of bracket that I can't see in the pics ?

I'd like to loose that bracket/crossover on my Sportster too, but most of the slip ons that I've seen need it, and the full systems are too expensive for me.

Title: Re: Oxygen Sensor
Post by MMRanch on 11/05/16 at 17:57:50

Yea guys that's the same mufflers
I'm won't be home till Monday afternoon for more pictures , but
The original heat shield covers the 1.75" end.
The rear mounting bracket goes to the rear foot-peg.
The front mount goes to the mid-mount peg holes :-*
Also
I put a 1\4" bolt through the connection of: muffler-clamp , muffler , and header-pipe / all three layers , just to make sure they can't come off :).

The connector pipe is heavyer than both new mufflers put together :)

Title: Re: Oxygen Sensor
Post by MMRanch on 11/07/16 at 21:06:19

I know most anybody could come up with a better mounting system , and I might do something different after thinking about it for a while but :

For the front muffler

First idea I had on mounting these mufflers are these.

I welded a group of nuts together to make a really long nut for the front mount , then mounted the "supplied" mounting bar to the mid foot-peg frame holes with enough bar left over to reach the stud on the muffler. Then put in the nut column on muffler then a bolt from the bar. Hope the picture makes it more clear. ::)

Title: Re: Oxygen Sensor
Post by MMRanch on 11/07/16 at 21:11:06

OK

The rear :

I welded a "L" bracket on the end of the Supplied Mounting Bar to reach the rear foot peg. Hope the picture shows it good. ::)

Under the "Heat-Shield" (from the top) is a 1/4" short bolt threaded through all three layers of Muffler-clamp , Muffler , and Header Pipe ;) just for added insurance against muffler blowing off on the road (both front and rear). The internal baffle is the weakest link in the chain now ! 8-)

Versey , You rode my Sportster up at Daves place for a bit , don't know if you noticed the vibration that was going on then --- but its all gone now ! :)

Don't base your Sportster point-of-view on the way it felt then . its back to its "Old-Self" now 8-)

Title: Re: Oxygen Sensor
Post by Dave on 11/08/16 at 03:35:56

I wonder if the vibration was the muffler insides rattling around?

Did you look inside your problem muffler and notice the insides looking like they disintegrated?

Title: Re: Oxygen Sensor
Post by oldNslow on 11/08/16 at 05:35:57

I wonder if you might want to consider making some sort of flexible mounts between the mufflers and the frame.

I think Harley designed that funky bracket/crossover thing when they rubber mounted the sporty engine, so that the entire exhaust system. including the mufflers, could move with the motor. Nothing on the oem setup is bolted rigidly to the frame.

A short piece of rubber between the bolt on the muffler, and the bolt in the frame so the mufflers can move a bit. Right now your headers are moving with the engine, but the mufflers can't.

This is for a car, but something similar is what I'm thinking about.
https://www.summitracing.com/parts/wlk-36272?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-

I might be over thinking this. May not be an issue at all. But I think I'd keep a close look at the mounts and the header/muffler joint for a while just to be sure. The rubber mounted engines move around a lot more than than the old sportsters that were solidly bolted to the frame.

Title: Re: Oxygen Sensor
Post by Dave on 11/08/16 at 06:24:42

I believe oldNslow makes a good point about the mounts. Your engine is mounted in rubber, and when idling it bounces around a bunch, and I am sure it moves around similarly as you apply throttle and shift gears. It would not be a good thing to have the headers mounted to the engine, and the muffler supports mounted to the frame in a way that won't allow movement.

Title: Re: Oxygen Sensor
Post by MMRanch on 11/08/16 at 11:50:39

I wonder if the vibration was the muffler insides rattling around?

Na , The rear Oxygen Sensor had set a "Rich Condition" code.

Ya'll are right about the flexable mounts ,I'll start thinking on that ! ::)

Something mounted to the same place the original was but without the tubes . :-? ... Aluminum ?