12-07-2020, 06:11 AM | #1 |
Join Date: Jun 2020
Location: A small country with a funny name
Posts: 164
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Small oil capacity = more frequent oil changes?
I was reading a review of the new 2020 SWM RS 300 R (not a chinabike, sorry ;-) and among others, the article said that the oil capacity had been increased to 1.8L, thus bringing the oil change interval (OCI) up to 2000 km (dunno up from what though).
Now, my experience with my Zongshen ZS200-GY2 (same engine as the Yamaha TW200) is that its nominal 1.1L of oil (effectively 1L coming out during changes) gets punished pretty badly, and at least mineral oils don't cut it for longer than 500-600 km before being turned into a thick sludge when cold and a water-thin concoction when hot. So OCIs are pretty short. OTOH 1.1L doesn't sound so little considering the capacity of the engine (197cc) and its low power (15 HP). A 1400 cc car will have anything from 3.5-5L of oil in comparison, so if anything the small Zongshen/Yamaha TW200 engine appears plentiful and overengineered. Then again it is air-cooled and the oil also does triple duty as a gear oil and a wet clutch fluid.... For comparison, a Honda Cub 50/70/90 takes about 0.6-0.7L of oil, which seems like even more in proportion. Then again those small bikes are most often ridden in punishing stop & go city traffic and don't even have a proper oil filter... So, do even slightly larger oil capacities help with oil longevity, just by themselves? Last edited by ChillRider; 12-07-2020 at 10:41 AM. |
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12-07-2020, 07:25 AM | #2 |
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An oil cooler will just about triple the oil life on the little engines. On both my Hawk and X22R i went from changing the oil every 500 miles to 1500-2000 mile. When I do change the oil it will be no where near as dark as without the oil cooler. Before the warm weather hits next year I'll be adding one to my Ghost as well. The oil cooler will greatly reduce the oil temperature which in turn increase the oil life.
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12-07-2020, 08:29 AM | #3 |
Join Date: Jun 2018
Location: Florida
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What JerryHawk said is pretty much it, I'm guessing the BMW is liquid cooled, and therein lies where the heart of the matter lies, combined with the points you already mentioned yourself. These small, air cooled motors run hot, and heat is the number one cause of oil degradation.Anything you can do to reduce the heat or increase capacity will help - and as you yourself noted, these oils are pulling triple duty , i myself would guess that clutch plate contaminants were at least as prevalent as actual engine item wear particles in used oil , but that black coloring usually isn't due to contaminants, it's from plain old the oil being cooked due to the high temps ,and many of the smaller engines are now also revving to highs that were unheard of not that long ago, which certainly aint helping the equation any , either.
I have to agree 100% with the idea of running an oil cooler on these small engines.
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12-07-2020, 09:17 AM | #4 |
Join Date: Oct 2020
Location: Flower Mound Texas
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A little different take on oil contamination in years of messing with small engines is this. Engines that share their oil with the transmission (and clutch) have much shorter oil change intervals than ones with separate oil supplies. It's usually clutch and gear wear that fouls up the oil first. Sure heat breaks down the oil and forms carbon, but on bike/atv motors it seems clutch and trans wear are worse offenders....
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12-07-2020, 10:36 AM | #5 |
Join Date: Jun 2020
Location: A small country with a funny name
Posts: 164
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Nah, I really meant SWM, not BMW (although BMW did actually have a stake in SWM some point). But trivia aside, yeah, they were talking about a liquid-cooled model. Having nearly 2L of oil to foul up compared to, dunno, 1.2L or 1.5L, must account for something; but still, a claimed 2000 km OCI doesn't sound like much for a liquid cooled engine....
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12-07-2020, 12:52 PM | #6 |
Join Date: Nov 2017
Location: Marseille, France -> Conakry, Guinea
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SWM is owned by a Chinese company, and it's never technically been owned by BMW. Husqvarna was Italian owned starting in 1987, until 2007, when BMW owned them until KTM bought Husky. BMW helped build a plant in Italy for Husky, whose plant and engine designs are now used by SWM. It's a bit convoluted, to say the least.
Another important factor that hasn't been mentioned is state of tune, for example, the CRF250L makes next to no power (I owned one for about 20k km), but only specifies 12k km oil changes for 1.8l of oil, which, while a bit long, I changed the oil at 8k km twice and it wasn't too bad. The SWM/Husky motor, while street legal, is much closer to a racing 250, and is much harder on the oil than the aforementioned 250L. KTMs tend to have really small oil change intervals, too. |
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12-07-2020, 08:29 PM | #7 |
Join Date: Apr 2017
Location: Omaha, NE
Posts: 8,100
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The shorter interval with a small capacity comes down to two main factors. Thermal and mechanical capacity.
Thermal is easy. The more oil you have, the more oil there is to collect heat and shed heat before it reaches critical temps where viscosity, shear strength, and compression resistance are degraded. Over time this degrades the molecular bonds of the molecule chains, reducing the oils ability to do its job. The mechanical is related to thermal, but also can be independent. As others have mentioned the oil takes a serious pounding serving double duty as gearbox oil and engine oil. The mechanical forces do degrade the molecule chains in the oil over time as well. The more oil you have in the system, the more it resists the conditions that break it down and the more there to take the abuse before it degrades and thus spread it out over a longer interval
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12-07-2020, 09:43 PM | #8 |
Join Date: Apr 2018
Posts: 819
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I copied Jerry and the boy’s oil cooler advice and it takes about 3 months of daily driving before the oil turns black like a car. I use the synthetic stuff and it stays brown in the glass window for ages. My motor is at nearly 16,000 miles and no issues yet.
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12-07-2020, 09:58 PM | #9 |
Join Date: Apr 2017
Location: Omaha, NE
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Yeah, the oil cooler definitely makes a difference. I am pretty conservative with my oil change intervals and go every 1k miles.
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12-08-2020, 08:44 AM | #10 |
Join Date: Nov 2017
Location: Marseille, France -> Conakry, Guinea
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Since the SWM is based on something with a higher state of tune, I wouldn't expect getting as much benefit out of an oil cooler as something that is more thermally challenged, like CG motors (relatively speaking). There's a lot more shear going on in motors that spin as high as the SWM, all of the internals are subject to greater forces in higher specific output motors.
An oil cooler will increase the capacity, as Dan mentioned, and you'll get some benefit from that, but if I were you, I'd look at what Husky people were doing in terms of what oil you should use and what maintenance intervals people were actually doing. It was called the TE310, if that helps. |
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