11-06-2022, 12:16 AM
If there is one sure fire thing about oil in the last decade or so is the drive to less viscous oils to boost fuel efficiency. You can see plenty of 5W-30, 0W-30 and even 0W-20 oils on the shelved nowadays. You really don't want to go up to a 10W-40 unless your ambient temperatures warrant it. I was riding in 109 Deg F in that Californian heat waves little while back, that warranted a 10W-40 for sure. Me on the other hand just melted.
I have just seen the case of a Triumph owner complaining his bike has started smoking from the exhausts and he was looking for possible reasons, he was burning oil. He had admitted to using a heavier weight oil on his last service and had just changed it back on the current service to the correct lighter specification. It only started smoking with the oil change back to the new lighter weight. I am willing to believe he could have worn his valve guides with repeated poor top end lubrication. I can't be sure 100% that is what has happened, but it is the only variable. The newly changed correct lighter weight oil probably exposed the wear and got through the valve guides and into the combustion chamber. An engine designer doesn't randomly choose an oil weight and diverging from recommended weight is folly.
I have just seen the case of a Triumph owner complaining his bike has started smoking from the exhausts and he was looking for possible reasons, he was burning oil. He had admitted to using a heavier weight oil on his last service and had just changed it back on the current service to the correct lighter specification. It only started smoking with the oil change back to the new lighter weight. I am willing to believe he could have worn his valve guides with repeated poor top end lubrication. I can't be sure 100% that is what has happened, but it is the only variable. The newly changed correct lighter weight oil probably exposed the wear and got through the valve guides and into the combustion chamber. An engine designer doesn't randomly choose an oil weight and diverging from recommended weight is folly.