This is an archived version of the Road Star Clinic. The Road Star Clinic can now be found at www.roadstarclinic.com. Please join us there!

Road Star Forum
Welcome, Guest
Please Login or Register.    Lost Password?
Re:The great fuel injected Roadie
Go to bottom Post Reply Favoured: 5
TOPIC: Re:The great fuel injected Roadie
#674669
Aussie John (User)
Platinum Boarder
Posts: 1937
graphgraph
User Offline Click here to see the profile of this user
Re:The great fuel injected Roadie 4 Years, 6 Months ago  
You could try using a higher octane fuel, it has better cleaning additives and burns cleaner, even if you used it every say 3rd tank that might help, John
 
Logged Logged  
  The administrator has disabled public write access.
#674683
Gadgetman728 (User)
I've live in pursuit of the next adventure
Gold Boarder
Posts: 852
graphgraph
User Offline Click here to see the profile of this user
Gender: Male Location: Middle Of Kansas Birthdate: 1960-07-28
Re:The great fuel injected Roadie 4 Years, 6 Months ago  
I Rode about 125 miles Saturday and by the time I got home the back plugs were fouled again. It's only getting worse.
I have a brand new set of stock plugs, I'll install them today.

Aussie - I was using 91 octane, everyone here said it wasn't needed, so I've gone back to 87.

I can't afford to just start changing parts out. I'm starting to suspect the o2 sensor is bad. How do you test the sensor while running? Thanks all!! Gadget
 
Logged Logged  
 
Last Edit: 2013/08/18 06:37 By Gadgetman728.
 
  The administrator has disabled public write access.
#674700
texasscott1 (User)
Two of a kind
Platinum Boarder
Posts: 4486
graphgraph
User Offline Click here to see the profile of this user
Gender: Male
Re:The great fuel injected Roadie 4 Years, 6 Months ago  
Look in the wiring diagram and find the wires that are the sensor. The other 2 wires are for the heater. Hook a low DC voltage meter in those wires and watch the voltage at idle and when the engine is revved. The sensor should respond to the different mixtures. If you can carry the volt meter while riding at a steady cruise you should see the output hunting back and forth between high and low as the mixture is changed. During acceleration the voltage should go high because of the richer mixture. If the O2 sensor isn't working the output will be sluggish or noexistent.

To see what it should look like you can check the output of the front cylinder sensor.

If the output of the sensor is okay then check all of the connections back to the computer. If the sensor is reading constantly lean (low voltage) then it's probably bad since that cylinder is obviously running rich. If it's reading constantly rich then the problem could be an injector or the computer or even a bad sensor connection.

Edit: I guess you could also swap the front and rear O2 sensors and see if the problem moves to the front cylinder.
 
Logged Logged  
 
Last Edit: 2013/08/18 08:59 By texasscott1.
 


My 99 Standard Test Mule
Scott B.
  The administrator has disabled public write access.
#674721
River (User)
Platinum Boarder
Posts: 2847
graphgraph
User Offline Click here to see the profile of this user
Gender: Male
Re:The great fuel injected Roadie 4 Years, 6 Months ago  
I think you could swap the o2 sensors out as a fairly quick test. Great Idea Scott.

My next project is to drill for another bung on the other pipe so that I can get an AFR reading on the back jug, and compare them to the front jug.

I'm really curious about gadgetmans problem, and what it takes to solve it.

If a person can get to the suspected injector, you can listen for the injector to turn on and off as you crank it.

Another thing that can cause rich mixtures is a leaking injector, but it costs very little for a qualified shop to test the injectors, and have them cleaned. I'm thinking it was 6.00 per injector is what I paid the last time. That was at NAPA.
 
Logged Logged  
 
  The administrator has disabled public write access.
#674741
out2lunch (User)
Senior Boarder
Posts: 388
graphgraph
User Offline Click here to see the profile of this user
Gender: Male Location: Southeastern MI
Re:The great fuel injected Roadie 4 Years, 6 Months ago  
Not having read through all the pages here, the rear jug plugs will always be blacker than the front jug plugs. If you've got a bad O2 sensor, you will experience a stutter at constant speed the ECM will default to very rich mixture when it's not getting a reading from the O2 sensor and at constant speed it seems to have trouble keeping things balanced. (This has been my experience).

However, when I say black, it's black in comparison to the fronts which look perfect.
 
Logged Logged  
 
  The administrator has disabled public write access.
#674743
blue_star (User)
Platinum Boarder
Posts: 6570
graphgraph
User Offline Click here to see the profile of this user
Re:The great fuel injected Roadie 4 Years, 6 Months ago  
out2lunch wrote:
Not having read through all the pages here, the rear jug plugs will always be blacker than the front jug plugs. If you've got a bad O2 sensor, you will experience a stutter at constant speed the ECM will default to very rich mixture when it's not getting a reading from the O2 sensor and at constant speed it seems to have trouble keeping things balanced. (This has been my experience).

However, when I say black, it's black in comparison to the fronts which look perfect.
I have to disagree with you. When I changed the plugs in mine recently, there was no difference in the front and rear plugs.
 
Logged Logged  
 
  The administrator has disabled public write access.
#674889
Gadgetman728 (User)
I've live in pursuit of the next adventure
Gold Boarder
Posts: 852
graphgraph
User Offline Click here to see the profile of this user
Gender: Male Location: Middle Of Kansas Birthdate: 1960-07-28
Re:The great fuel injected Roadie 4 Years, 6 Months ago  
Out to lunch - I'm pretty sure it's going to be the O2 Sensor. It HATES a constant speed, anywhere throughout the range. You described what's happening perfectly. Bobz Bikes is 30 miles from here and I have $85 credit with them, so I'm headed over there tomorrow morning to see if they have an O2 sensor in stock.

Blue Star - Our bikes are so much the same, I like hearing how your bike is acting. - Gadget
 
Logged Logged  
 
Last Edit: 2013/08/19 01:09 By Gadgetman728.
 
  The administrator has disabled public write access.
#675022
Gadgetman728 (User)
I've live in pursuit of the next adventure
Gold Boarder
Posts: 852
graphgraph
User Offline Click here to see the profile of this user
Gender: Male Location: Middle Of Kansas Birthdate: 1960-07-28
Re:The great fuel injected Roadie 4 Years, 6 Months ago  
Found a damaged wire right where the wires enter the O2 sensor, look like someone twisted it too much.
Bobz bikes can order me an O2 sensor for $178, I'll get the Bosch one, recommended on another thread, from amazon for $54.98 and wire it myself.
 
Logged Logged  
 
  The administrator has disabled public write access.
#675046
texasscott1 (User)
Two of a kind
Platinum Boarder
Posts: 4486
graphgraph
User Offline Click here to see the profile of this user
Gender: Male
Re:The great fuel injected Roadie 4 Years, 6 Months ago  
If it's one of the wires that goes to the sensor portion of the O2 then that's going to be the problem. The sensor outputs such a low voltage that those two connections and wiring have to be without any resistance. The heater wires carry a higher voltage and aren't as critical.

When wiring in the replacement I would suggest soldering the wires to the stock O2 connector wires so it can be plugged into the bike wiring. Just make sure the heater and sensor wires are connected correctly.
 
Logged Logged  
 


My 99 Standard Test Mule
Scott B.
  The administrator has disabled public write access.
#675157
blue_star (User)
Platinum Boarder
Posts: 6570
graphgraph
User Offline Click here to see the profile of this user
Re:The great fuel injected Roadie 4 Years, 6 Months ago  
I must have missed the cheaper O2 sensor. Do you have a link to the one on Amazon? I couldn't find it.
 
Logged Logged  
 
  The administrator has disabled public write access.
Go to top Post Reply
Powered by FireBoardget the latest posts directly to your desktop
...................................................................... ...................................................................... ...................................................................... ...................................................................... ...................................................................... ...................................................................... ...................................................................... ...................................................................... ...................................................................... -->
New Forum Posts


The Road Star Clinic is a collaborative community of riders who archive and publish user contributed technical data about Yamaha Road Star motorcycles.

Copyright 2003-2007 Road Star Clinic and its respective authors.
<-- -->