Transmission Oil Choices, What To Pick

[Rockey]

There’s a lot of controversy about which oil is best in a wet-clutch type two stroke motor. There are also a lot of options out there to put in that high dollar transmission. Synthetic or Dyno? What weight? And most importantly, can I use automotive oils in my bike?
Lets start w/ Synthetic Vs. Dyno oil. Theres a lot of advantage to synthetic oils. One of the most important ones is lubrication. On a 4 stroke, you are told not to use synthetic on break in. This is because the superior lubrication does NOT allow the rings to seat. For the rings to correctly seat, there must be a degree of wear. So synthetic lubricates better. That’s good. Can it lubricate enough for the clutch to slip? In some instances the answer is yes, we will discuss that later. Synthetic also resists breakdown at high temps, for example, Mobil 1 5w-30, a very light oil, will protect and resist breakdown up to 400 degrees Celsius, which if an engine ever reached it would be a glob of melted aluminum. Synthetic also won’t separate at low temps (below 40) like a heavier weighted dyno oil will.
Lets talk about clutch slippage. It can happen with dyno oils, it can happen with synthetic oils. The factor is not synthetic or dyno, its Energy Conserving or not. Its often heard that synthetic will cause slippage, but that’s not entirely true. While some synthetics will, others won’t. The thing to look for is the Energy Conserving logo on the back of the oil bottle. You don’t want energy conserving, what it means is the oil contains friction modifiers which reduce friction. This is great in a car, because the clutch is separate from the engine. This lets the engine have less drag, and supposedly increase fuel economy. The problem is, in a wet clutch, the oil lubricates the clutch, and the clutch needs some form or friction to grip the fiber to the steel plates.
So we are down to this, synthetic is better quality, and it needs to be a NON Energy Conserving blend of synthetic oil. But what weight? There are many different weights of oil. 5w-30, 10w-30, 10w-40, 20w-50, etc. What do those weights mean? The w part (10w) tells how the oil will be weighted like when the engine is cold and first starts. The lower the temp, the lower you want the W rating. The other number is the weight the oil mimics while the engine is at operating temp. Particular oil weights almost ALWAYS have the EC label, these weights are 5w-30, and 10w-30. Other weights usually don’t have the EC label. Pick oil weight by your outside temperature. A 30 weight is good for winter, while a 40 or 50 weight is good for summer.
Ok, does everybody understand oil weights? Good. Now lets look at some synthetic oils that are good choices for your bike.
I’ll start with Mobil 1. Mobil makes 3 great synthetic oils for our bikes. The 15w-50 is good for summer temps or hot running bikes (XR’s). There is also a 0w-40 blend which is great for spring and summer temps, and a 0w-30 which is nice for cold winter days. Many people don’t know of the 0w-40 and 0w-30, but they are both great oil. I personally always use Mobil 1 oils. They really are THAT good. There are others that are good too. Castrol Act-Evo, Klotz Pro Drive 30, and Honda HP4, which I have used and liked, but it all comes down to personal, and bike preference. I have always have best luck with the Mobil oils, and will stick with them. Plus they are a bargain for synthetics.
Now for the last question. Can I use automotive oils in my bike? As long as the don’t have the EC tag, then yes, you certainly can. A lot of people disagree with this however. Some motorcycle oils have zinc and phosphorus to stop wear. They use these because they can’t use friction modifiers in the oils. Zinc and phosphorus aren’t used in car oils because the harm catalytic converters. It’s a trade off, but when you pay double the price for Mobil 1 15w-50 for cars by buying the MX4T motorcycle blend, it’s a waste of money. The 15w-50 is just fine.
Hope this is useful, if you’ve got any questions, please ask.

[Dell30rb]

Nice!

[Blitz393]

thanks for the info! looks like i'll be gettin' some Mobil 1 20w-50 in my bike. i was using the Yamalube gear oil, because i needed some gear oil right NOW, and didn't have time to go somewhere else. Thanks for the great read!

-Rob

[VirginRider]

in the 2 stroke forum I have heard ATF to be used in many 2 stroke bikes gearboxes since its changed every 1 to 2 races/rides. Is there any truth to this? Also what to use in an air cooled 4 stroke ATV? No mention in 4 stroke discussion forum.

[Dell30rb]

I've used ATF in my 125's gearbox. It works fine, but dosent last as long as some of the other lubes i've tried.

[brokenbones]

I just changed mine to ATF, $2 a quart vs $4 something for mobil. I think it is a good idea to change the fluid as often as possible so I went with the cheapest fluid I could get. I was useing redline at $13 a quart but I felt bad changing the fluid after a short ride or after sitting a while, so with ATF I change it every time I ride the bike. According to Dirt Bike Magazine ATF is the fluid of choice, not just because of the price, but because of the quality as well. If shelling out more spendolies for synthetic makes you feel more comfortable then go right ahead, but you can use ATF and still feel secure.

My never to be humble opinion

[dirtytrixx400]

i agree with Rockey.....mobile1 user myself...15w50synthetic.i've used non-synthetic for years too,with no clutch or trans failures ever.

atf is a very low viscosity oil base...dexron II is/was a 20wt base.if your using any of the newer blends they were made to be an even thinner type fluid.

atf has no rust or moisture protection.
this would only be a concern if you let your bike sit a long time...it probably wouldn't matter what you used as far as storage would matter.....the best thing would be occasional use to circulate oil and to build up heat to drive moisture out.

the AMSOIL site has lots of info on it....good info there too.

[MATTXR250R]

Since I have owned my CR250R..I have used 3 different types of tranny oil...For the first few months I used Bel-Ray Gear Saver 80W. I loved it..Very pleased...but I was paying $5.85 a liter at the dealer so then I tried some Mobil-1 15W-50 REDCAP...I hated it. It would make my clutch drag ALL the time. I changed it the other day and put in some ATF Type F that was $1.22 a quart..I am VERY PLEASED. Doesn't cause the clutch to drag since its not a thick. I WILL change it more often but I am gonna use ATF from now on.

[MATTXR250R]

I am using Type F ATF..LOVE IT!! I hated Mobil-1 15W-50 REDCAP..made my clutch drag ALL the time.

[Spitfire]

matt, what's the difference between ATF oils, you said you were using "Type F", what's the difference? what are some other ATF oils you can use??

[Spitfire]

And just to confirm, would it be alright to use SAE 10W-40 Synthetic Blend in my tranny on my RM?????

[dirtytrixx400]

the different types of fluids were produced as newer models of transmissions were introduced....type f and the later version type fa have more friction modifiers for ford trans....dexron was actually developed for a softer shift feel.the newer versions dexron III,merconV,toyota type4,etc...all were developed for specific problems needing addressing by the newer model trans(torque converter shudder,slow flow rate thru valve-body&solenoid packs,etc..).

believe me...trans fluids were designed only to satisfy the performance designs/goals of a automatic automotive trans...not the demands of a motorcycle gearbox.
also this is worth mentioning too...some trans fluids will swell/soften rubber components and others will shrink them.

[Woody_393]

Originally posted by MATTXR250R
I am using Type F ATF..LOVE IT!! I hated Mobil-1 15W-50 REDCAP..made my clutch drag ALL the time.

Good to hear you hated it

Sorry about that matt, I like it in my tranny, but then again, I've not tried ATF either.

[Woody_393]

Oh and isn't Type F less slick then the mercron dexron stuff?

[MATTXR250R]

LOL Woody.

Sorry about the Double post. I posted the first reply and it didn't show up on the thread...so I typed the shorter one because I didn't want to type all that over again..and I be darned..I just checked this thread and there both up:.

Anyhow...I know the MObil-1 is good oil...just didn't agree with my bike. And since ATF is so cheap...I will change it more often.

[Woody_393]

No worries matt, I'm not attached to Mobil in any way. Just glad you found something you are happier with.

[KTM250rm393]

spitfire,

You can use a high quality 10w-40 racing engine oil like valvoline, quacker state, etc. as long as it doesn't say ENERGY CONSERVATION in the API rating circle. Energy Conservative means it has friction reducers which is BAD for the clutch unless you want your clutch to start slipping. Mobil-1 15w-50 red cap is used by alot of 4 strokers.

I've tried it several times on my KTM and it worked just as good as my Bel-Ray Gearsaver 80 wt.

[Spitfire]

ok, thanks guys!

[low430]

I was going to use automotive oil in my 02 cr250r tranny but everywhere i went people did backflips telling me to use the honda specific stuff, So I had the option of the GN4 honda 4stroke stuff or the HP racing honda transmission stuff

I went with the HP racing stuff but it scared me cuz it says 80/85w on the bottle but its the only stuff the honda dealer stocks.
The parts guy convinced me it was the right stuff so Im runnin it at the moment.

[belly]

i went to the honda/yamaha dealer today, and asked them what they recommended for a yz 125 (tranny oil). they told me "Pro Honda HP trans oil SAE 80w/85W". This is my first 2 stroke bike, so my question is, is this the right stuff? thanks