What does high oil temps really do to bike oil?

[vindex1963]

Originally Posted By: Blaze
I have an oil temp dip stick on my Honda Xr 400 off-road bike and see around 200-225*.


That's a good temp. My Ultra's in dash oil temp peaks at 300 and on a 110+ day it would bury it.

 

[Blaze]

The Xr 400 has a real nice oil cooling system. It uses the frame for an oil tank plus has an oil cooler located in the front part of the bike between the upper fork tubes,, right below the handle bars. My friends has a Xr 650 with no cooler and he can see 275*.

 

[Ducati996]

I helped my son perform an oil test for his High school project which consisted of heating engine oils while monitoring the temperature and recording changes. Premium Synthetics slowly turned dark, some more than others. One major brand mineral oil had a sudden violent, foaming reaction that caught fire.
Our results of 12 different motor oils showed that the oils will get dark & thicken when overheated in a very short time span, in some instances seeconds.
Sudden color change(can)be a sign that the oil has been overheated and needs to be changed.

 

[BigCahuna]

Just heating an oil until it catches fire, doesn't prove or disprove anything. Any oil in any motor doesn't sit in one spot with heat applied to it to the point it catches fire. voa's and uoa's both give flashpoints so exceeding that point is meaningless.,,

 

[OnTheFence]

Originally Posted By: Ducati996
I helped my son perform an oil test for his High school project which consisted of heating engine oils while monitoring the temperature and recording changes. Premium Synthetics slowly turned dark, some more than others. One major brand mineral oil had a sudden violent, foaming reaction that caught fire.
Our results of 12 different motor oils showed that the oils will get dark & thicken when overheated in a very short time span, in some instances seeconds.
Sudden color change(can)be a sign that the oil has been overheated and needs to be changed.


I bet you found out that premium synthetics take longer to cool down than do dino oils?

 

[vinu_neuro]

Seriously, just send the oil to a lab that tests oxidation like Polaris or Wearcheck and you'll find out how your oil copes with high temps. Blackstone gives you very little compared to the others. No TAN, oxidation, nitration, etc.

 

[bkingrider]

I ride a Harley 03 deuce with the twin cam 88 motor and use castrol syntex 15 50 oil and have an electronic therometer that measures temps in the oil bag. On longer trips moving at about 80 mph the bike runs in the 220 range consistantly. Ambient temps are in the 80 to 95 range.