Bike runs hot on freeway load conditions

[bieber]

My 03 XB9s runs hot under constant freeway load, eventually the light comes on, this happens faster on hot days but still happens on mild ones. When flogged on backroads it is OK as long as the throttle gets varied. Other than this, the bike runs great and gets very good mileage, maybe too good. I have put 12,000 miles on it in 8 years (it now has 17,000), but they were 5 miles freeway/5 miles in-town each way commute trips. A move to a distant residence revealed this issue.

The original owner had the Buell hot-rod ECM, muffler & air filter kit installed when the bike was brand new.

I installed the right side scoop, and I changed the CHT sensor with a factory part in case the computor was getting a false reading, but it still happens.

The issue MAY be getting worse/progressing, it is hard to tell. Can it be running kind of lean because of an o2 sensor starting to fail (from age & mileage)? Is a lean condition an indication of their failure?

Any ideas?!!!!!!!!!!!!

 

[rchuff]

Could be 02 sensor.

 

[NCScuba]

I dont have a buell yet but Ive been looking and researching through this site and over at badweb...

I was thinking that maybe one or both of the fuel injectors arent squirting enough...
Or possible the fuel pressure regulator is getting weak

 

[go cytocis]

Causes of overheating per the troubleshooting guide in the manual:
- insufficient oil supply
- clogged or damaged oil cooler
- bad fan
- leaking valves
- carbon deposits
- retarded ignition

 

[jimijeans]

Since you have a 2003 model bike. Check your Fan! when at home on the Stand or Kick Stand get a home fan let it push air in front on the Front Cylinder. IF you have one if not don't worry about it. Run the Engine and wait for the Fan on your Bike to come on.
It should only take at the most 7/minutes to come on while Idling only! If the fan does not come on either the Temperature Sensor on the rear Cylinder head could possibly be bad or the Fan itself.
BEFORE you Start the Engine Gently try to spin the Blades on the fan in case something has fallen in there or a Fan Screw has fallen out and so on.
Sometimes removing the seat is better for workability.
If the bike runs fine when it is dead cold on start up usually the sensor is bad if after 7minutes or the wiring to it could possibly be shorted or the 2 speed fan has a problem. Check that Very Soon! OR no Buell for you to ride. Hope it is an Easy fix. Always check your fuses and relays first. NEVER put a larger fuse in if it is blowing the fuse. OR your wiring will catch on fire.
Always put in the Exact Proper Fuse. If the Fan Circuit Fuse blows when the Temperature Sensor is turning it on then usually it is the fan or a short in the wiring. Do the Small Things First If you keep riding it and overheating the Engine it won't make it very long. Check the manuals at the top of the page should you need to look at something in that area.Good Luck.*Jimi

 

[user_deleted]

bieber: i owned a 2003 xb9r for 2 years or so and probably logged 3000 freeway miles on it during that time. many of those miles were in 90+ air temps at 70mph or slightly higher. never an activated CEL, never had ecm go into "limp-home" mode, never an over-heating issue. this was with stock left scoop and optional right scoop as is yours. i say it is fueling or timing or both on your bike. worth trying to borrow a stock ecm specific to your model, replicated the conditions now causing your over-heating conditions and see what happens.

 

[nivtim]

Have you checked you've a good oil supply?

 

[bieber]

It really does not seem to have any system problems, such as the fan, oiling etc...

I used to work on large air-cooled piston aircraft engines for a living, and the way it reacts to load, RPM & outside air temperature etc..., both getting hot and what I do to cool it back down, seems to be an across the board slightly lean condition. Not lean enought to normally cause drivability issues, but lean enough to be on the edge and surface as running hot in the worst conditions (I would love to have a CHT gauge!). I wonder if it was the first crack by Buell at the "race" ecm tune back at the beginning of 2003 and it biased towards power, I can ride it like a track day on the back roads and the problem does not surface.

Since I do not have a stock ecm to try, I will probably start with a new O2 sensor just to make sure the existing one is not biased to rich and causing the bike to lean out.

Also, I get 60+ mpg at best (55 mph constant), 44 riding hard and 50 commuting. What do you guys get?

 

[jimijeans]

Mileage on the V Twin varies, depending on Rider and Shape of vehicle the fuel used but your are on pretty much close to target with that mileage, Most times with fuel mileage like that the 02 sensor is working unless a wiring issue hasn't been found yet. IF your Engine doesn't Rattle badly when the light or Cel light comes on usually the Timing is good .
Does Not hurt to check it.!! With age of the vehicle a few( new parts) is not a bad idea. I know I have plenty! All engines are EPA regulated for lean IDLE conditions .for motorcycles to pass. the lean condition that is required, in the fuel maps & epromm for the Pre Programed ECM/ ECU for the bikes is necessary. Techs. and the like would have to Manually change the setting .then Re-saved to the Brain (ECM / ECU- through your Computer. A tech and I am one Can Not legally change a ECM/ECU due to EPA crap.
Or just don't get caught. Now, YES I like Clean AIR to Breath Too!
I always post the most simple items in NON Tech Language to check first trying to save all riders money. Small things first, unless obvious and Testing whether it is counting the blinks by using the Data Port Plug, or Software in your computer When the problem occurs is a good way to save your money, before
Throwing parts at it hoping to solve the problem. I Realize not everyone can read the Fuel Maps and Epromm. The Buell XB site can help you with that should you want to learn more about that. Also it doesn't hurt to replace parts as a preventive measure to prevent break downs and such.
Overheating however is Hard on Any Engine Air Cooled or Liquid.so your first testing area is simple.Try the Cooling unit (FAN/ Temperature Sensor/ Relays/ Fuses Connections & fans Wiring is the easiest for testing. for ANY Engine like I posted earlier.
Usually when the Yellow light comes on either you have a Charging issue coming your way OR the Cooling system may be in need of Attention. IF it just so happens to turn out that fuel pressure or oil pressure is the problem then Use some SeaFoam in the FUEL Tank to a fill up. You should get 3 Fill ups to ONE can of Seafoam . Change the Oil Filter and prime the Filter About 3/4 full with Marvel Mystery Oil. LET it soak in then spin it on!
Then run the Oil for at least 200 miles after that in case there is buildup in the Oil lines and areas. A Oil Pressure Guage can be installed also to check for the proper Oil pressure.A Cheapy will work JUST FOR TESTING.. I Have Several Guages on the 4 bikes I own LiQuid Filled OIL/ Fuell/ Volts all mechanical by Marshall industries MADE in the USA!, yes it cost me some money but Engines are Expensive and when customers come to my Uncles shop they really check out the 1125 CR Buell and the XB12R- both 08s.. That Said,.I Hope it is an easy fix. Ride Safe. *Jimi .

 

[user_deleted]

Also, I get 60+ mpg at best (55 mph constant), 44 riding hard and 50 commuting. What do you guys get?

exactly the same on a 2003 xb9r, 2007 xb9 city, 2007 xb12 uly, 2010 xb12 ss

 

[bieber]

First, thank all of you for your time trying to help me, it is really appreciated.

Does anyone know what temperatures set off the check engine light, the initial light "on" and the later, when hotter, light "blinking" & subsequent the skip-spark mode?

After the installation of the right side airscoop, I have never had it reach the point of the blinking light, only the light coming on. It is easy to get the light back off with a reduction in power and a little compression braking (i.e. closing the throttle and letting it pump some air). I am wondering if I am not really at a dangerous temperature, just getting near it, and am safe if it never blinks (and running synthetic oil)?