Just done another oil change on my KTM390 Duke, something which I am very familiar with doing on the numerous motorcycles and cars I've owned in my 48 yrs of riding 'legally' on the road. Mostly straightforward, Drain oil from hot engine, remove filter, on bikes- possibly tilt from side to side to get every last drop of oil out, sometimes I even turn engine over by hand or quick flick of the starter button without engine starting to pump the last few drops out. I have found that with this particular bike when I refill with fresh oil (after prefilling new filter with oil) to the correct level in the sight glass after starting the bike and allowing to idle for a few mins, the sight glass is now showing completely full ( over filled), but leave it overnight and when I check again there is no oil showing in the sight glass at all. The procedure shown in the handbook is to check oil level one minute after switching off engine on a warmed up engine. So I have been buggering about , draining excess oil with a syringe and thin fuel pipe to remove excess, bit of a tricky job to get it exactly right! Anyhow whilst doing a bit of research I came across this: This is very interesting on power loss due to oil reaching the crank on acceleration or deceleration: Ask Kevin: Can Adding Too Much Oil Lead To Engine Damage? | Cycle World QUESTION: When refilling the crankcase for an oil change, it would be nice to achieve the perfect level exactly at the full mark. If it is a little low, it’s no big deal; you just have less of a buffer if the level goes down over time. But overfilling seems to be a different story. The owner's manual for every bike I have owned has had the words: “Do Not Overfill.” Unfortunately, they have never explained why. What’s the truth behind Do Not Overfill? What harm does too high of a level cause? Is a “little bit” over the full mark bad? Greg May Union, Kentucky ANSWER: Motorcycles are capable of accelerating and braking very hard—slightly over 1g either way. This means that the oil surface in the engine’s oil sump tips forward a bit more than 45 degrees during hard braking and tips back a like amount during maximum lower-gear acceleration. The oil sump is baffled in such a way that this oil movement cannot a) slosh oil onto the crankshaft above, a condition that would generate great heat and drag; or b) allow the oil pump’s pickup tube to suck air, even for an instant. But there are limits; an overfilled oil level may be too much for this baffling, allowing oil to reach the crank. If sump oil splashes onto the spinning crank, it turns the crankshaft and crankcase into a high-horsepower oil pump with no outlet. Scores of horsepower go into accelerating the oil to approximately 200 feet/second, yet the oil can’t get away; it is swept around the case by the whirling crank. The late Dick O’Brien, longtime Harley race chief, once told me, “You could see the power loss when one of our KR engines would wet-sump on the Daytona straightaway. It was like a giant hand had just slowed the thing down.” When oil got between the crank and its close-fitting crankcase, it was batted between crank and case, creating huge viscous loss—and each horsepower lost became 746 watts of heat. A loss of, say, 20 percent of engine power (0.2 x 60 hp = 12 hp) was thus the same as having 12 kitchen toasters going full blast inside the crankcase.
I do wonder if I overfilled my triumph and this is what happened, rather than oil starvation. Stupid dipstick idea and no sight glass...
tbh, in my naivety I had only really considered the repercussions of overfilling to be excess oil being forced out of the crankcase breather and either vented to atmosphere or into the air box depending on what system used. I hadn't given power loss any consideration! In today's modern engines, such as your Trumpet, I can now imagine there could be very negative repercussions if overfilled!
Why not just put in the makers recommended amount?? if they say 4ltrs its 4 ltrs! you can only be a bugs dick out if at all,
I agree with the above, use a measuring jug and put in the makers recomended amount. After that note where the oil level is and if necessary maintain it at the mark. I use this method myself to avoid the problem of overfilling, did it once and never again. Luckily it just made a mess where oil was forced out of the crankcase.
The makers will give an oil change amount with filter, or if you know better measure what comes out! but wtf do i know i'v only been doing for 40yrs
In my experience, if the oil is overfilled by more than a small amount - (small amount being variable, depending on which engine it relates to) - it will either be pumped out because of crankcase pressure through the crankcase breather to open air on older bikes or via the airbox on more modern bikes - either way there are tell tale signs the engine is overfilled. However - now that I am running a Harley Sportster if you think you have issues getting the correct level, try looking up the palaver I have to do. Still, it's all part of the learning curves regardless of which bike - and a bit of fun, too - like trying to find the right / suitable oil at the right price. Contrary to what you might think, Harleys don't run on creosote or molasses.
In Ducati engines, unlike KR Harley-Davidsons, the crank is not close fitting. There is loads of room all around the crank in our generously-sized crankcases, so the problem mentioned does not arise.
I've never seen a "change amount" only how much it holds. And if you measure what comes out goes back in you are assuming what came out was the right amount.
Did the oil change on my uncles speed trip (mechanically inept uncle)... couldn't beleive my eyes when he showed me the dip stick.
I did, minus the amount that was held in the filter that I didn't replace. Trouble is, the many was vague...and with a dipstick that changed in model year but you could barely tell the difference....
Which is why Harley Sportsters don't have a wet sump and have a separate oil tank for engine oil (and the clutch and gearbox run in a separate compartment in the engine case).
Overfilling with oil also may place oil seals under extra pressure. Resulting in them letting go a bit.
At what point did I say that? I'm fully happy with my system and it works well for me (touch wood). This year I have dome 4 oil changes on 3 bikes with 0 issues so far. Please feel free to post "how much oil to put back in after draining oil" for the KTM 390 rather than the amount of oil it holds from dry.
Experienced enough to not be adding the amount of oil the manual says my sump holds after draining it.
