15w-40 user opinions

[cWj]

While changing my stator, I decided to go ahead and do an oil change and try the 15w40 I'd seen mentioned in the wiki. I had been using Rotella T6 5W-40. I've also recently switched to Iridium plugs.

Now the bike seems to have more tendency to stall pulling away from a stop, yet it also seems a bit less clackety once it is warmed up well.

So, for those who have used or do use 15w, what have been your observations in use? I've read elsewhere that people feel like it gives smoother shifting, fewer false neutrals. I would agree until last night when I had a mess of them, though I don't discount my periodic shitey shifting.

I need to take a look at the plugs, too...will likely switch the plain NGK back in for spell to see how it feels. I may even drain a bit out and add some T6 back in for giggles.

And, as Rhett Butler as my witness, I will manage to successfully replace that blasted filter gasket.

[gsJack]

First off I wouldn't put a 5W-anything dino or full syn in an air cooled bike engine.  I ran 15W-50 Mobil 1 full syn in my 97 GS for 50k miles and switched to less expensive 15W-40 Rotella dino when oil consumtion increased.  Got same oil mileage with the 15W-40 for less cost.  Proved to my satisfaction that an anything-40 runs cooler in an air cooled bike than an anything- 50 does.

Have gone with the 15W-40 Rotella dino in my 02 for all it's 100k miles and have no complaints with it.  I put in one change of 20W-50 dino in it late last year and it quieted the 100k mile engine noticeably.  Went back to the 15W-40 again making 3 oil changes while trouble shooting it for a knock this spring and it's getting noisy as it gets hotter this summer and will probably go back to the 20W-50 again, I don't ride as far or as often or on 90F days like I used to. 

[Suzuki Stevo]

Rotella T3 

[cWj]

Rotella T3 

care to elaborate?

[cWj]

First off I wouldn't put a 5W-anything dino or full syn in an air cooled bike engine.  I ran 15W-50 Mobil 1 full syn in my 97 GS for 50k miles and switched to less expensive 15W-40 Rotella dino when oil consumption increased. 

Hm. Never saw any consumption or leaks in 2K miles of 5W T6 full synth from Oct-May in NY weather.

[gsJack]

While changing my stator, I decided to go ahead and do an oil change and try the 15w40 I'd seen mentioned in the wiki. I had been using Rotella T6 5W-40.......................... it also seems a bit less clackety once it is warmed up well.........................

I think your answer is right there.  The viscosity breakdown that takes place as the miles add up tends to reduce the viscosity when hot down closer to the min rating so the 5-40 becomes thinner than the 15-40 did when hot.

There are some long stringy molecules of something in multi viscosity oils that are chopped up by the gears in the bike tranny causing viscosity breakdown to be more rapid than in applications that don't use the same oil for both engine and tranny.

[cWj]

I think your answer is right there. 

I don't see how the noise could be from breakdown given I'd heard it since I got the bike last October. I changed the oil (no idea what was in it before) to the T6 5W soon thereafter. From that point I've ridden two thousand miles.

But my question is about other people's observations using the different grades, not about what is causing the sound, though I realize that might have been unclear since I incorrectly typed the post title as "!5w-40"...

[Suzuki Stevo]

Rotella T3 

care to elaborate?

Rotella T3 15w-40 $12.97 a Gallon at Wallmart, better shifting and less clatter than Rotella T6 5w-40 when hot, I'm with Jack, 5w would be a good choice for riding an air cooled bike in Alaska...in winter

EDIT: So far the only test bike that has had both T6 and T3 in it is my WR250R, most noteable, the shifting seemed more notchy with the T6 5w-40

[Rallyfan]

I've switched from Suzuki 10W-40 to Rotella T5 16W-40 just now. First impressions are the motor is quieter, and the shifts more positive -- though I found it harder to downshift into 1st.

I ride on local freeways. Ambient temps routinely exceed 30C, and speeds are from stop-and-go to 120 kph for 65 km distances twice daily. The 15W-40 seemed an interesting idea.

[cWj]

and none of you folks experienced the need to feather more carefully from stopped after the switch to 15w?

[Suzuki Stevo]

I've switched from Suzuki 10W-40 to Rotella T5 16W-40 just now. First impressions are the motor is quieter, and the shifts more positive -- though I found it harder to downshift into 1st.

I ride on local freeways. Ambient temps routinely exceed 30C, and speeds are from stop-and-go to 120 kph for 65 km distances twice daily. The 15W-40 seemed an interesting idea.

It is one of the options! 

[GS4me]

and none of you folks experienced the need to feather more carefully from stopped after the switch to 15w?

Do you actually notice that you need to do that with the 15W ? 

Does anyone run 20-50 and feel that they have to feather from a stop (sorry, Don't mean to hijack the thread).  I don't ride in the Winter  (Certainly not below the 40 degree mark), and I've considered 20-50 as well.

I'm curious if others notice the same thing.  I've been contemplating switching to the Rotella 15W 40 but I haven't as of yet.  I'm getting close to oil change time.

Following this tread closely...  Great topic

[dinkydonuts]

The oil nerds at BITOG found that Rotella T5 actually retains its additive package a lot longer than Rotella T6. I think it works great, but has a very distinctive smell.

[Suzuki Stevo]

The oil nerds at BITOG found that Rotella T5 actually retains its additive package a lot longer than Rotella T6. I think it works great, but has a very distinctive smell.

The farther the 2 weights are apart the more polymer's are used, polymers are coiled when cold, and unwind as the oil heats up. The uncoiled polymer chains regulate the viscosity of the heated oil. 5w-40 has more polymer's in it than 15w-40, and supposedly polymer's are beat to crap by motorcycle transmissions? This could be part of? And please note I didn't stay at a Holiday Inn Express last night.     

[prmas]

I have been using 20w50 off and on for most of the bike's life and find that it definitely shifts better, especially in hot weather (40C+ here). I always allow 3 or 4 minutes warmup while I put on the helmet and gloves to ensure there is plenty of oil flowing before I move off. I also change the oil every 2000km! Oil is cheap, metal is NOT.   

[The Buddha]

I use accel 10-40 in all bikes. Walmart issue, SF rated.

Except when the bloody thing isn't available like a couple years ago. Then its Delo 15-40 or Rotella 15-40, both of which I have parts of atleast 3 gallon jugs.

Yes GS likes 10-40, but as you get higher oil consumption, the thicker oil works better. I do think the 50 runs hotter, but that also cos likely the 50 doesn't boil off at as low a temp, and besides if you use oil, you likely are losing it at the cyl wall, and temperature is your friend cos things seal up better at the cylinder if it was hotter. I suspect its not that big a factor one way or another tho.

Cool.
Buddha.

[cWj]

and none of you folks experienced the need to feather more carefully from stopped after the switch to 15w?

Do you actually notice that you need to do that with the 15W ? 

Well, I noticed something. That's why I brought it up. I have the impression that it stalls easier. It could just be my evolving shift habits - maybe I'm just more relaxed about the possibility of a stall and apply throttle later, but I have definitely noticed the lumpy spots below 3K rpm more with the heavier oil. I've only calculated MPG once since the change, so not really enough data there to infer anything.

[gsJack]

http://gstwins.com/gsboard/index.php?topic=67546.msg813384#msg813384

[Suzuki Stevo]

Well, I noticed something. That's why I brought it up. I have the impression that it stalls easier. It could just be my evolving shift habits - maybe I'm just more relaxed about the possibility of a stall and apply throttle later, but I have definitely noticed the lumpy spots below 3K rpm more with the heavier oil. I've only calculated MPG once since the change, so not really enough data there to infer anything.

Take your bike out for about an hour ride and get the oil good and hot, as soon as you get home take all the slack out of the clutch cable then tie the clutch lever back to the grip and leave it overnight, take two drinks and get back with me in the morning about your stalling problem 

EDIT: Above helps minimize the clunck when dropping in to 1st from "N" more than anything

[prmas]

Agreed, Stevo. Oil viscosity cannot have any effect on stalling or otherwise. I always hook my clutch lever back when I am parking the bike overnight to prevent clutch "stick" in the morning. That solved my 1st gear clunk a long time ago. During the day it is not necessary. I have a half-done cable tie (zip tie) that fits nicely around the heated grips controller when riding and slips over the left grip/clutch lever for longer term parking.

Macka