Small oil capacity = more frequent oil changes?

ChillRider · 12-07-2020, 06:11 AM

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?

**JerryHawk250** · 12-07-2020, 07:25 AM

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.

RedCrowRides · 12-07-2020, 08:29 AM

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.

TxTaoRider · 12-07-2020, 09:17 AM

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....

ChillRider · 12-07-2020, 10:36 AM

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....

franque · 12-07-2020, 12:52 PM

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.

Megadan · 12-07-2020, 08:29 PM

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

ChipToothy · 12-07-2020, 09:43 PM

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.

Megadan · 12-07-2020, 09:58 PM

Yeah, the oil cooler definitely makes a difference. I am pretty conservative with my oil change intervals and go every 1k miles.

franque · 12-08-2020, 08:44 AM

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.

12-07-2020, 06:11 AM	#1
ChillRider Join Date: Jun 2020 Location: A small country with a funny name Posts: 164	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
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,578	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. __________________ 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel
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12-07-2020, 08:29 AM	#3
RedCrowRides Join Date: Jun 2018 Location: Florida Posts: 759	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. __________________ 2001 Mustang GT 2004 Sportster 2018 VADER 2020 Orion RXB250L
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12-07-2020, 09:17 AM	#4
TxTaoRider Join Date: Oct 2020 Location: Flower Mound Texas Posts: 904	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.... __________________ 2021 Tao Tbr7 - "Lucille" Mods so far- Brozz swingarm, 21" front rim (Bridgestone Tw302 rear/Dunlop D606 front tires), Digital gauge cluster, pz30b pumper carb, after market hand guards, aftermarket brake and clutch levers, round fold away mirrors, Fly handlebars shortened slightly, 13t front sprocket 2009 Q-link Legacy 250 1982 Suzuki GS1100ES - "Jolene"
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12-07-2020, 08:29 PM	#7
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,042	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 __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
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12-07-2020, 10:36 AM	#5
ChillRider Join Date: Jun 2020 Location: A small country with a funny name Posts: 164	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
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	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, 09:43 PM	#8
ChipToothy Join Date: Apr 2018 Posts: 819	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. __________________ Bashan Storm: Ebay steel exhaust wrapped, folding shift lever, seat mod, vm26 carb, air pod, dual led scrambler headlamps, windshield mod, led brake/tail light, secondary led brake light (swingarm), Ebay 295mm rear shock, back up CDI (racing unknown), oil cooler, digital gauge cluster,
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12-07-2020, 09:58 PM	#9
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,042	Yeah, the oil cooler definitely makes a difference. I am pretty conservative with my oil change intervals and go every 1k miles. __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
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12-08-2020, 08:44 AM	#10
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	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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