fuel dilution issue

pb3 · October 27th, 2016, 04:32 PM

Hi all,
Original owner of a '14 (purchased feb '14), stock, now with 4.6k miles.

At the second oil change (nov. '15 w/ 2.8k miles, 2.4k miles on oil) I mailed an oil sample to OAI. Report came back severity 4 (worst) for fuel dilution (greater than 5%). That was with K. OEM 10w40 organic.

Next oil change (aug '16 w/ 4k miles, 1.2k miles on oil) mailed another. Came back severity 3 for fuel dilution (4.2%). Oil was amsoil mcv 20w50

I have 3 other bikes, all with oil analysis in their history. None have shown an issue like this. My ex650 had a 2.7% report i contributed to excessive idling from TB sync/ tune up.

My first thought was a stuck open thermostat but comparing various spots with a IR temp gun to my other bikes the temps seem identical. I'll also plan on inspecting the air filter. Beyond that could it be a leaky injector- yet I have no black soot at the exhaust, no other anomalies.

Anyone else found similar or have thoughts of what to look for?

tia,
parker

jkv45 · October 28th, 2016, 06:59 AM

Do you do a lot of short trips? How long do you let it warm-up? Short trips and extended idling for warm-up will cause a rich mixture, but extended riding should burn it off. Once it's fully warm, do you rev it often or run it at lower RPMs mostly?

I would add some fuel system cleaner like Techron Concentrate (1oz per gal) to the next tank or 2.

If it's none of the above, I would expect a leaky injector might do it.

EDIT: Don't run 20W-50. No need for it. Synthetic oil is better, heavier oil is not.

VaFish · October 28th, 2016, 08:23 AM

Quote:

The causes of fuel dilution can be
the result of many things:
• Leaking injectors
• Excessive idle time
• Incomplete combustion
• Cool engine operating conditions
• Frequent short trip driving
• Performance chips/engine modifications
• Restricted air filter/bad air to fuel ratio
• Worn piston rings/excessive blow-by
• Incorrect choke settings
• Towing/lugging engine
• Fuel pump/over fueling
• Seals and gaskets
• Improper injector timing

From:

http://www.amsoil.com/techservicesbu...20Dilution.pdf

adouglas · October 28th, 2016, 08:57 AM

What to look for... hmm.....

Personally I'd look for the key, go ride and stop obsessing about potential issues on a new engine until there's an actual symptom of something wrong.

Note that five of the things in that AMSOIL list have absolutely nothing to do with anything mechanical.

Note also that the trend is improving. Perhaps the engine is just wearing in normally. Who knows? Point is that it's running just fine. Go enjoy the ride.

Oil analysis on a brand-new bike? Really?

Over-measuring things can be misleading. At any given moment, for example, something about your health will be sub-optimal. Your heart rate or blood pressure might be high. Your temp might not be 98.6. You might be a bit overweight. You may feel a bit odd. None of that means you're sick or will drop dead.

pb3 · October 28th, 2016, 01:49 PM

Quote:

Originally Posted by jkv45

Do you do a lot of short trips? How long do you let it warm-up? Short trips and extended idling for warm-up will cause a rich mixture, but extended riding should burn it off. Once it's fully warm, do you rev it often or run it at lower RPMs mostly?

I would add some fuel system cleaner like Techron Concentrate (1oz per gal) to the next tank or 2.

If it's none of the above, I would expect a leaky injector might do it.

EDIT: Don't run 20W-50. No need for it. Synthetic oil is better, heavier oil is not.

I should have explained that better... all of my bikes experience the same riding behavior. No short trips. Only extended idling I'd consider was on my first bike (250) and learning proper warm up with a choke.

Thus when this bike's report came back twice with this issue, I felt it necessary to inspect before potential damage.

I will consider the cleaner except that my understanding of it contributing to blow-by instances on a automotive oil sample. Was directed to run the cleaner before the oil change interval due to what is collected in the crankcase so it may further skew my sample results.

And yes, 20w50 far too much for this engine. I was only using the oil viscosity/ temperature suggestion chart in our manuals.

If an injector was leaking, would I experience longer than usual crank time as the pump built back up pressure? How best to determine a leaky injector? Remove the spark plugs and smell for raw gas?

SLOWn60 · October 28th, 2016, 03:04 PM

You had a 250 but don't say if you had it analyzed. I doubt this is the reason but is it possible you are not running at a high enough rpm? These motors need to scream or you're lugging them. Just throwing it out for your consideration. Regular riding should be 9,000+ on the tach.

rgx107 · October 30th, 2016, 02:08 AM

I haven't had the oil analysed but when changing it there is a foul smell from it. Last time I had the oil sitting in the open pan for a few weeks, the smell went away eventually. I attribute this to residues from unburnt petrol. Another classic sign of petrol in the oil is that the oil level goes up, then drops after a longer ride - haven't seen those variations, though as little as 5% could be difficult to spot. That's around 1 dl of oil. If anything, the oil level on my bike is higher after hard riding since the oil expands with temperature.

About the thermostat, it doesn't govern the temperature in normal riding since it opens already at 55 C.

The only other difference from your other bikes is that the 300 has very large injectors for such a small engine, apparently the same part number as in the ZX6/636. I think this contributes to less optimal fueling, especially at low load and when the engine is cold. So there will be fuel that isn't burned, some of it will end up in the oil. (Bigger engines increasingly have two injectors per cylinder now, because it wasn't possible to get good fueling at all loads with only one injector.)

I have no experience from leaking injectors but undoubtedly the bike should run badly. Or will have trouble starting if it leaks down into the cylinder when the engine is off. You should have noticed something. The EFI lamp should light up if an injector is bad as well.

Another theoretical possibility is that the pressure regulator leaks, it should have one port connected to one of the intake ports. It should give similar symptoms as a leaking injector.

October 27th, 2016, 04:32 PM	#1
pb3 ninjette.org member Name: parker Location: STL Join Date: Apr 2009 Motorcycle(s): 09 n250, 14 n300, 22 n400 Posts: 98	fuel dilution issue Hi all, Original owner of a '14 (purchased feb '14), stock, now with 4.6k miles. At the second oil change (nov. '15 w/ 2.8k miles, 2.4k miles on oil) I mailed an oil sample to OAI. Report came back severity 4 (worst) for fuel dilution (greater than 5%). That was with K. OEM 10w40 organic. Next oil change (aug '16 w/ 4k miles, 1.2k miles on oil) mailed another. Came back severity 3 for fuel dilution (4.2%). Oil was amsoil mcv 20w50 I have 3 other bikes, all with oil analysis in their history. None have shown an issue like this. My ex650 had a 2.7% report i contributed to excessive idling from TB sync/ tune up. My first thought was a stuck open thermostat but comparing various spots with a IR temp gun to my other bikes the temps seem identical. I'll also plan on inspecting the air filter. Beyond that could it be a leaky injector- yet I have no black soot at the exhaust, no other anomalies. Anyone else found similar or have thoughts of what to look for? tia, parker

October 28th, 2016, 06:59 AM	#2
jkv45 Rev Limiter Name: Jay Location: WI Join Date: Jul 2013 Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes Posts: A lot. MOTM - Jun '18, Oct '16	Do you do a lot of short trips? How long do you let it warm-up? Short trips and extended idling for warm-up will cause a rich mixture, but extended riding should burn it off. Once it's fully warm, do you rev it often or run it at lower RPMs mostly? I would add some fuel system cleaner like Techron Concentrate (1oz per gal) to the next tank or 2. If it's none of the above, I would expect a leaky injector might do it. EDIT: Don't run 20W-50. No need for it. Synthetic oil is better, heavier oil is not. Last futzed with by jkv45; October 28th, 2016 at 09:21 AM.

October 28th, 2016, 08:57 AM	#4
adouglas Cat herder Name: Gort Location: A secret lair which, being secret, has an undisclosed location Join Date: May 2009 Motorcycle(s): Aprilia RS660 Posts: A lot. Blog Entries: 6 MOTM - Jul '18, Nov '16, Aug '14, May '13	What to look for... hmm..... Personally I'd look for the key, go ride and stop obsessing about potential issues on a new engine until there's an actual symptom of something wrong. Note that five of the things in that AMSOIL list have absolutely nothing to do with anything mechanical. Note also that the trend is improving. Perhaps the engine is just wearing in normally. Who knows? Point is that it's running just fine. Go enjoy the ride. Oil analysis on a brand-new bike? Really? Over-measuring things can be misleading. At any given moment, for example, something about your health will be sub-optimal. Your heart rate or blood pressure might be high. Your temp might not be 98.6. You might be a bit overweight. You may feel a bit odd. None of that means you're sick or will drop dead. __________________________________________________ I am NOT an adrenaline junkie, I'm a skill junkie. - csmith12 Nam et ipsa scientia potestas est. Heri historia. Cras mysterium. Hodie donum est. Carpe diem.

October 28th, 2016, 03:04 PM	#6
SLOWn60 n00bie to wannabie Name: Bill Location: St Ives, BC (Shuswap Lake) Join Date: Sep 2015 Motorcycle(s): 2012 250R (Red), 2005 VFR800A (Red), CRF450X (Red), 2012 F800GS (Wants to be Red!) Posts: A lot. MOTM - Nov '15	You had a 250 but don't say if you had it analyzed. I doubt this is the reason but is it possible you are not running at a high enough rpm? These motors need to scream or you're lugging them. Just throwing it out for your consideration. Regular riding should be 9,000+ on the tach. __________________________________________________ The Smart Money: #1 - ATGATT, #2 - Training (machine skills and survival skills), #3 - The bike; whatever floats yer boat with the money you have left over

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October 30th, 2016, 02:08 AM	#7
rgx107 ninjette.org member Name: Rolf Location: Sweden Join Date: Jul 2014 Motorcycle(s): Ninja 300 Posts: 70	I haven't had the oil analysed but when changing it there is a foul smell from it. Last time I had the oil sitting in the open pan for a few weeks, the smell went away eventually. I attribute this to residues from unburnt petrol. Another classic sign of petrol in the oil is that the oil level goes up, then drops after a longer ride - haven't seen those variations, though as little as 5% could be difficult to spot. That's around 1 dl of oil. If anything, the oil level on my bike is higher after hard riding since the oil expands with temperature. About the thermostat, it doesn't govern the temperature in normal riding since it opens already at 55 C. The only other difference from your other bikes is that the 300 has very large injectors for such a small engine, apparently the same part number as in the ZX6/636. I think this contributes to less optimal fueling, especially at low load and when the engine is cold. So there will be fuel that isn't burned, some of it will end up in the oil. (Bigger engines increasingly have two injectors per cylinder now, because it wasn't possible to get good fueling at all loads with only one injector.) I have no experience from leaking injectors but undoubtedly the bike should run badly. Or will have trouble starting if it leaks down into the cylinder when the engine is off. You should have noticed something. The EFI lamp should light up if an injector is bad as well. Another theoretical possibility is that the pressure regulator leaks, it should have one port connected to one of the intake ports. It should give similar symptoms as a leaking injector.