10' Yz450F Fuel in the oil?

[thestuz]

Blackstone's instructions warn you specifically NOT to do that.

these engines overheat when left idling for 30 seconds.........

surely 10 mins warm up would be ample time ?

i figured 20 mins would be for a slow warming car engine?

[grayracer513]

these engines overheat when left idling for 30 seconds.........

surely 10 mins warm up would be ample time ?

i figured 20 mins would be for a slow warming car engine?

Sorry, it doesn't work that way. Every cold start contaminates the oil with fuel. Since gasoline is soluble in virtually every motor oil, it's more difficult to get back out than to mix in. It's not a matter of simply reaching a warmed up state, either, but rather, the engine must be run with OIL temperatures above 160 degrees for at least 20 minutes to purge gasoline from the oil by evaporation.

If you are going to do an oil analysis, you should drain the sample after the engine has been run and ridden in its normal manner and before the next time it is cold started. If you aren't taking the sample as the engine cools down at the end of the ride day, don't "warm up" the engine before you change the oil. On a carbed bike on a hot summer day, a "cold start" can cause a 2-6% fuel contamination, throw your viscosity readings way off, and generally render the entire sampling a complete waste of time and money.

[Chazmagnum]

@ Grey. Now that makes cense. The fuel being able to evaporate at proper running temp makes the whole thing a lot less scary. It seems some of the fella's are having good luck with themostats or covering the radiators, but this does apear to be a band-aid fix. With that said I never ride in sub freezing temps. (32f 0c) Like some of the hardcores on here. So I am still curious if there is a possible electrical or fuel management fix???

[grayracer513]

The true fix would be either a factory installed t'stat and/or a reprogramming of the fuel delivery software at the core level (not what you can do with the tuner).

I recall a post in which the owner of a 2010 claimed he was seeing low coolant temps even in 50 degree weather so a thermostat is probably the best route to go.

[rickallen124]

Sorry, it doesn't work that way. Every cold start contaminates the oil with fuel. Since gasoline is soluble in virtually every motor oil, it's more difficult to get back out than to mix in. It's not a matter of simply reaching a warmed up state, either, but rather, the engine must be run with OIL temperatures above 160 degrees for at least 20 minutes to purge gasoline from the oil by evaporation.

If you are going to do an oil analysis, you should drain the sample after the engine has been run and ridden in its normal manner and before the next time it is cold started. If you aren't taking the sample as the engine cools down at the end of the ride day, don't "warm up" the engine before you change the oil. On a carbed bike on a hot summer day, a "cold start" can cause a 2-6% fuel contamination, throw your viscosity readings way off, and generally render the entire sampling a complete waste of time and money.

I agree that not getting up to operating temps along with multiple cold starts probably caused alot of my fuel contamination. One 8-10 minute moto per hour just isn't enough to ever get it up to operating temps and each start makes the problem worse. I'm going to pay close attention to coolant temps next time I ride and decide if covering the radiators is the right thing to do. I think I'm going to cut my oil change intervals in half untill the track gets back to were I have 20-30 minute motos.

[powers450f]

Sorry to bring this post back from the dead but am wondering if there are still people dealing with this problem.. I have an 11 yz450f and the oil smells like gas after an hour or two of riding??Thanks

[norcal_hoss]

Sorry to bring this post back from the dead but am wondering if there are still people dealing with this problem.. I have an 11 yz450f and the oil smells like gas after an hour or two of riding??Thanks

Yes I posted a thread the other day its probably on page 2-3 .

I had a 2010 and never had the issue and I always smell my oil after draining it.Now on my 2011 ive changed the oil twice on it both times it smells like gas.The oil is very thin feeling and im not really happy about it. Taping of the radiator may help but its not the answer. I think more people need to pay attention to there oil and if they have the smell of gas in it tell your dealer or call yamaha direct. This can not be good for the clutch and the bottom end. Im riding Sunday and dumping the oil when I get home. If it has the gas smell in it im taking it back to the dealer either to get a new one or have them fix it. It has 4 hours on it. If you find anything out please post about it id really like to know what is the problem and how to fix it asap.

[andy250]

Yes I posted a thread the other day its probably on page 2-3 .

I had a 2010 and never had the issue and I always smell my oil after draining it.Now on my 2011 ive changed the oil twice on it both times it smells like gas.The oil is very thin feeling and im not really happy about it. Taping of the radiator may help but its not the answer. I think more people need to pay attention to there oil and if they have the smell of gas in it tell your dealer or call yamaha direct. This can not be good for the clutch and the bottom end. Im riding Sunday and dumping the oil when I get home. If it has the gas smell in it im taking it back to the dealer either to get a new one or have them fix it. It has 4 hours on it. If you find anything out please post about it id really like to know what is the problem and how to fix it asap.

Norcal - Have you measured amount of oil that comes out? My oil smells heavily of fuel at every oil change. However, I measure the volume each time, and I always get the exact amount that I put in (~950 mL).

Please measure the volume. It may be a non-issue. It takes very little gas to make your oil stink, especially if you're using VP-U4, or similar...

[grayracer513]

The best answer is to do a used oil analysis. I still think that there are two different things going on. One caused by excessive temperature enrichment brought on by low coolant temps, and another that happens less frequently in which there is a leaking injector to blame.

[powers450f]

Yes I posted a thread the other day its probably on page 2-3 .

I had a 2010 and never had the issue and I always smell my oil after draining it.Now on my 2011 ive changed the oil twice on it both times it smells like gas.The oil is very thin feeling and im not really happy about it. Taping of the radiator may help but its not the answer. I think more people need to pay attention to there oil and if they have the smell of gas in it tell your dealer or call yamaha direct. This can not be good for the clutch and the bottom end. Im riding Sunday and dumping the oil when I get home. If it has the gas smell in it im taking it back to the dealer either to get a new one or have them fix it. It has 4 hours on it. If you find anything out please post about it id really like to know what is the problem and how to fix it asap.

YES this is my issue too and would like some more current input on this issue. Thanks

[powers450f]

The best answer is to do a used oil analysis. I still think that there are two different things going on. One caused by excessive temperature enrichment brought on by low coolant temps, and another that happens less frequently in which there is a leaking injector to blame.

Thats what I was thinking too about low temps, I just don't want it to be a leaky injector with only 6 hours on the bike. Idk if this is a major or minor problem that maybe we are over examining?? Not sure either way, I will defiantly be changing my oil more often.

[brentn]

Grey, should I send in my analysis after one good long ride, like an hour of non-stop riding or should I do it after a few rides (4 hours)?

I want to do this right, and I was figuring to only start the bike if it's to be ridden for more than 20 minutes, and to ride the bike like I normally ride it. I JUST changed the oil, left the filter and put in exactly 950ml and have not started it since. I'm going riding tomorrow and will not have a problem pulling up to the truck after an hour and grabbing a sample after it is about half drained.

what do you think?

btw, I have one rad blocked and in about 8 degree weather I was seeing a constant 65 degree's coolant temp, with spikes of 90-93 degree's and an average of about 69-70 the way I ride. I may block off a third of the second radiator and just see if that can bring the coolant temp up to the sweet spot of 80-90 degree's, unless you think otherwise.

Lets get this crap solved once and for all!

[powers450f]

Grey, should I send in my analysis after one good long ride, like an hour of non-stop riding or should I do it after a few rides (4 hours)?

I want to do this right, and I was figuring to only start the bike if it's to be ridden for more than 20 minutes, and to ride the bike like I normally ride it. I JUST changed the oil, left the filter and put in exactly 950ml and have not started it since. I'm going riding tomorrow and will not have a problem pulling up to the truck after an hour and grabbing a sample after it is about half drained.

what do you think?

btw, I have one rad blocked and in about 8 degree weather I was seeing a constant 65 degree's coolant temp, with spikes of 90-93 degree's and an average of about 69-70 the way I ride. I may block off a third of the second radiator and just see if that can bring the coolant temp up to the sweet spot of 80-90 degree's, unless you think otherwise.

Lets get this crap solved once and for all!

Just curious to how many hours you have on your bike, and if you have noticed this problem from day 1? Thanks

[brentn]

I've noticed it since day 1, a gassy smell of the oil. Really that's the only FACT that I have, weather or not the oil has been degraded or if this can be corrected will be told by the oil analysis that I plan on sending in if I get some feedback on test conditions.

I have 29 and a half hours on the bike now, I drained the oil a few days ago and it didn't stink as bad but was pretty black after only 4 hours of ride time. Again, color and smell don't mean shit unless the scientists confirm a problem through analysis.

[grayracer513]

Grey, should I send in my analysis after one good long ride, like an hour of non-stop riding or should I do it after a few rides (4 hours)?

There should not be a problem that skews the results by riding it more than once, or one day as long as the last ride of the day keeps the engine at operating temperature for at least 15-20 minutes.

[powers450f]

I've noticed it since day 1, a gassy smell of the oil. Really that's the only FACT that I have, weather or not the oil has been degraded or if this can be corrected will be told by the oil analysis that I plan on sending in if I get some feedback on test conditions.

I have 29 and a half hours on the bike now, I drained the oil a few days ago and it didn't stink as bad but was pretty black after only 4 hours of ride time. Again, color and smell don't mean shit unless the scientists confirm a problem through analysis.

True. Can't wait to see the results. I've been changing my oil every ride or race day because of the gas smell issue, and it is starting to get expensive at $15 a quart...

[brentn]

Alright, I'll get a good 4 hours on this oil, will update if everything goes well and send out asap.

[powers450f]

Alright, I'll get a good 4 hours on this oil, will update if everything goes well and send out asap.

Sounds good thanks

[yz450fcranker]

try getting the oil hot enough to release the excess gas out of the engine since gas evaporates easy it might get the gas out of the oil but it will still smell like gas at the end and make sure the petcock is on off and rev it till it stops and maybe a the gas will eventually disappear but seriously if you dont use a 450 to its full potential to get it running right then dont get one

[powers450f]

try getting the oil hot enough to release the excess gas out of the engine since gas evaporates easy it might get the gas out of the oil but it will still smell like gas at the end and make sure the petcock is on off and rev it till it stops and maybe a the gas will eventually disappear but seriously if you dont use a 450 to its full potential to get it running right then dont get one

It's a fuel injected Yamaha... There is no petcock...?