Jump to content

Low compression after 25.000 miles


Recommended Posts

  • Premium Member
I wonder if the smoke is from overfilling the bike with oil changes every 2k miles... I have had 2 differ dealerships put 3.5qt of oil in my FZ-07 and it barely takes 2.75ish qts of oil even with the filter getting changed... 
Also if you live in an area with summer and winter blends of gas you will notice reduced mpg with winter blend gas...
 
I would have thought that when the plugs were pulled to check compression it would have indicated by having oily plugs. Hmmm... was it ever mentioned what the condition of the plugs was when pulled?
 
 

Brick
2015 Yamaha FJ-09 "Red Molly"
2014 Yamaha Super Tenere' ES
1999 Suzuki SV650

Link to comment
Share on other sites

  • Replies 50
  • Created
  • Last Reply
 
image.jpg
 
I went ahead attempted to de-carbonized cyclinders by putting Seafoam in each cylinder (8 her soak time).  Upon removing air box I took a photo.  Notice the moisture staining at entrance hole for vent from engine breather (just below the filter).  Should I be getting that much moisture coming through this vent?
 
Someone mentioned lazy O2 sensor.  When I get back in town I will take 02 sensor out and testing it.   Does  anyone know of a good video to help me test unit.  I know these sensors can be tested by checking their voltage at room temp and then again upon being heated up, but I don't know how to check their reaction time?  Again thanks for the help.
Link to comment
Share on other sites

Just got the bike back today.  Compression readings were 175, 173, and 160 psi.  Leak down was 3% at 100 psi on all cylinders.  Yamaha recommended dealer shock the fuel with ring-free plus.  So far 1/2 tank has been run through it with additive.  Dealer says bike will continue to smoke as additive is run through bike.  I haven't checked exhaust with towel yet.  Will do that in next couple days.  If I pull tank i will check air box for moisture and take photos.  Thanks again for help.
 
Honestly, those numbers aren’t too bad. They may show either a valve that has tightened up or rings that are carboned-up.
 
3% leak down shows the combustion chamber is healthy.
 
Based on the data you provided, I think tearing into this engine without some other symptom will probably result in you paying for the repairs. As frustrating as it is, Yamaha will not pay for repairs unless a failure has occurred or wear is found to be abnormal and has a cause that cannot be easily blamed on the owner/rider/technician. This is pretty common SOP from any warranty company these days. And even extended warranties decline repairs if they are part of the exclusions, which most people don’t even realize their policy has.
 
Run the ring free. I’m assuming by you stating that they “shocked” it, that they mixed it at 1 oz per gallon of fuel. If that’s NOT how they mixed it, then I would recommend you run a tank with those ratios, before changing the oil and going back to a “maintenance” dose. The maint. dose doesn’t dump as much carbon into the oil, so you can use it every fill up (1oz per 10 gallons IIRC).
 
-Skip
 
****I previously wrote this and didn’t post it, sorry for the late reply****
Link to comment
Share on other sites

 
image.jpg
 
I went ahead attempted to de-carbonized cyclinders by putting Seafoam in each cylinder (8 her soak time).  Upon removing air box I took a photo.  Notice the moisture staining at entrance hole for vent from engine breather (just below the filter).  Should I be getting that much moisture coming through this vent?
 
Someone mentioned lazy O2 sensor.  When I get back in town I will take 02 sensor out and testing it.   Does  anyone know of a good video to help me test unit.  I know these sensors can be tested by checking their voltage at room temp and then again upon being heated up, but I don't know how to check their reaction time?  Again thanks for the help.
 
You need a scope to really check an o2 sensor correctly. The voltage varies so rapidly that a VOM can’t keep up.
That said, I’ve never googled/YouTubed testing one - I’m sure someone thinks they have a good hack out there.
 
Remember that our o2 sensors are Narrow band, meaning they operate from 0-1V dc.
 
Don’t worry about the vent moisture! It’s normal. Ever look in the air box/breather system of your car?
 
-Skip
Link to comment
Share on other sites

is it possible some airbox hoses got mixed up?... is the airbox drain tube plugged up/pinched?...was the bike just washed?
2012 wr250f - C-class 30+ age group
2015 fz-07- Hordpower Edition-80whp
2015 fj-09- Graves Exhaust w/Woolich tune by 2WDW @120whp
Link to comment
Share on other sites

I don't doubt that this guy is having a genuine issue... but I think this is an outlier in terms of the reliability of the oF the FJ-09 as a whole.

'15 FJ-09 w/ lots of extras...

Fayetteville, GA, USA

Link to comment
Share on other sites

Yeah it is a K&N filter.  It is not over oiled (I over-oiled it once and saw what a mess it made).  The bike wasn't just washed.  I genuinely believe the moisture in the air get developed in the engines breath-off system which is exited into the air box.  I just was not sure this was normal.  Sounds like it is.
 
I started the bike after a weeks worth of sitting and after a decarbonized each cyclinder and it started without smoking.  I rode it home from work.  The gas mileage is still only 40 mpg (horrible).  Once I got home I pulled O2 sensor.  It was darkened I cleaned it up.  Then put a voltmeter on it with a plumbers torch.  I could not get any voltage coming from the sensor on either the blue or white wire (which is supposed to let off 0.1 to 1.0 volts).  Which could be an indication that unit is bad.  Let's just say unit is bad I am not sure why I am not getting an error code in the diagnostic mode.  If any one out there has run any tests on their 02 sensor let me know.  The blackness on the sensor with clean plugs got me baffled.
 
 
 
Link to comment
Share on other sites

  • Premium Member
What about disconnecting the engine breath-off vent wrapping the hose with a sponge so it will not spew stuff and plugging that hole in the air box with gaffer tape or something like that? Might confirm or deny where the moisture is coming from. Also if it's really coming from the engine you can send an oil sample to a lab like blackstone-labs.com and they can check if there is anything wrong with the oil composition.
Link to comment
Share on other sites

Yeah, that sounds like a good idea.  I am going to talk to Yamaha about bench testing 02 sensor and see what they can do.  I will look at the web site for sample and see what they can be done.  Again I appreciate everyone's help.
Link to comment
Share on other sites

Yeah, that sounds like a good idea.  I am going to talk to Yamaha about bench testing 02 sensor and see what they can do.  I will look at the web site for sample and see what they can be done.  Again I appreciate everyone's help.
Unrelated to the problem but get the bike flashed and disable the O2... it will run better that way anyway. I hope you get to the bottom of it or find out its nothing.

'15 FJ-09 w/ lots of extras...

Fayetteville, GA, USA

Link to comment
Share on other sites

Yamaha won't help on testing 02 sensor.  I was told by dealer and Yamaha corporate that they need to whole bike instead of bench testing O2 sensor.  I went ahead and did some research and found that you got to get the sensor up 600 degrees F before it even engages (shows voltage). Thus 02 sensor checked out (good).  Both the internal heater and signal. Thus I am back to ground zero.  In the meantime I have ring-free in the tank (in hopes that that helps).
 
My understand is the flash tune only addresses the upper power band.  Thus the close loop portion (0 to 6,000 rpms). Is not effected.  Thus a flash want change fuel moisture at these lower rpms.
Link to comment
Share on other sites

The other thing I forgot to mention was the O2 sensor was operating (I put sensor back on the bike and watched the voltage changes as it was performing ) 0.9 volts which is a rich condition at the 02 sensor.  Thus the ECM should be adjusting to bring this down to 0.5 volt range.  But I wasn't seeing that adjustment.  I may need to to a better job of letting engine warm up and get to operating temp.
 
 
This not being adjusted goes hand in hand as why I have low compression reading due to carbon buildup.  Something is not working right and I can't figure it out.  I may try disconnecting engine evaporate system and then watch voltage level from O2 sensor to see if this changes (while engine is running).
Link to comment
Share on other sites

any fault codes still hanging out in the ECU? you can pull up the dia. menu via dashboard since you got a pre 2017...
2012 wr250f - C-class 30+ age group
2015 fz-07- Hordpower Edition-80whp
2015 fj-09- Graves Exhaust w/Woolich tune by 2WDW @120whp
Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.


×