Middle drive problem.

[BA80]

However, in my experience the synthetic even though it is a better choice for lubrication in any engine has proven to cause slippage issues with the wet clutches bathed in crank case oil such as ours in many cases.

[jwhughes3]

I agree with Howard....I ran 20w50 Mobil 1 full synthetic (V-Twin type for motorcycles even though ours is an inline 4 and not a v-twin) for over 7,000 miles on the 7kWUSCAN ride last year without leaks or clutch slippage. It was the only oil I felt comfortable using for extended Long-Distance riding without a change. (Great Ranger burned enough oil to keep it kinda clean anyway - about 6 liters over the trip).

Normally I use the Castrol 20w50 dino oil as its cheaper in 5qt jugs to burn and changing oil in the driveway is no big deal. But I won't hesitate to recommend the Mobil 1 or use it again on an extended trip.

John

[motoman]

Beg to differ with you on that Bonz! Use the lighter equivelant syn. in your final drive, and see how long final drive bearings last after a few LD rides.....as in several few thousand milers.

Figure there's an obvious reason my diff. in my F-350 uses 75-140syn. ONLY as diff. tag states. Bushings definitely didn't replace internal roller bearings, and no difference from earlier Dana diff. that used EP80-90w prior to synthetic lubes being the norm. The equivalent synthetic lube can take the pressure loads that the EP(extreme pressure)80-90w did, but does NOT have the 'cling' ability unless going to 75-140w viscosity when replacing 80-90 conventional EP diff. lube.

[Prisoner6]

75w-140 synthetic is not the equivalent of 80w-90 Dino oil. By saying that, it implies that 80w-90 is then equal to 75w-140. NOT!

Hi, Bonz-

I should have been clearer in my post ... what I was trying to say was that 75W-140 synth. is the synthetic equivalent to 80W-90 dino gear oil for our bikes.

And, by logical extension, you therefore shouldn't attempt to use 80W-90 synthetic in the middle gear/final drive on our Elevens.

So, if you are going to use 80W-90 in the mid/finaldrive, make sure it's conventional dino.

I was merely saying that the 75W-140 synth. is a much better choice than the 80W-90 dino for our particular bikes ... not that it is equal in every application,

or that 80W-90 dino can be substituted for 75W-140 synth. where the synth. is called for.

However, in my experience the synthetic even though it is a better choice for lubrication in any engine has proven to cause slippage issues with the wet clutches bathed in crank case oil such as ours in many cases.

I agree ... In my ZRX I run full synthetic engine oil, and it loves it ...

BUT in my SF, I will always continue to run 20W-50 dino.

[Bonz]

Good discussion! Edumacate me here, now that this has been brought up...

Why isn't 75w-90 synthetic a fine replacement for a Dino 80w or 90w? I have run 75w-90 in both drives since owning my SG. I beg to differ with the gloom and doom.

For your F350, it calls for a 75w-140 because that vehicle might be used for towing, so Ford calls for that oil for that reason. My Ford Expedition was the same way, as is my Grand Cherokee that has the towing package. Non towing package Jeeps call for 75w-90. Towing is a whole 'nother ball game.

No thinner than a 75w-140 on the bottom end, and the same 90w on the top end. Dino and syn are not rated differently. How is 75w-90 syn bad for the MD when Yamaha calls for 80w or 90w based on outside temp?

For the wet clutch slippage, the clutch in proper working order on an XS is no different than my ZRX, and the other 6 bikes I have owned and run synthetic in, with ZERO issues. Syn is not slipperier unless it has friction modifiers in it, and then it is not an oil for our bikes anyway... It is better base stock that holds up better to thermal and shear breakdown with synthetic oil. If it was slipperier to any extent, gas mileage would go up and in any vehicle I have owned synthetic made zilch for mpg improvement using the same weight sun vs. Dino.

[BA80]

First, He stated that 75w140 is a superior replacement for 80w90 but 80w90 is NOT a good replacement for 75w140 which is exactly correct. I actually think that 80/90 synth would work fine in both drives but the viscosity range of the 75/140 is better suited to the needs of both drives.

As far as the clutch slippage issue with synth in the crankcase. You stated that it would be fine as long as there are no additives. Correct me if I'm wrong here but synth IS an additive in itself. It's not really oil just a synthesis of oil. It is designed to decrease friction and does an excellent job. However, the clutch relies on friction to operate properly and if friction is reduced the subsequently it's efficiency therefore MUST be reduced.

The newer clutch friction materials are designed to work well in this environment but these older frictions were designed before synthetics were commonly available and in use. Unless that fiction material has at some time been replaced with a more advanced product there will most likely be issues.

I personally think that the synth is a far superior lubricant and use it in both drives where friction NEEDS to be reduced and it performs much better than the dino. I would use it in the crankcase also but every time I have attempted to it resulted in clutch slippage.

Some say that it works fine for them, possibly the friction material has been upgraded or possibly their riding style allows that the slippage isn't an issue.

My $.02

[Bonz]

Mobil 1, Valvoline, Castrol, Rotella, and most other normal synthetics are no more than the best of the best dino oil, and as such the base oil simply holds up better/flows better under extremes of hot and cold.

Some synthetics are still made synthetically, Red Line as one example I believe, and their claim to fame is they protect better than the synthetics I mentioned above because they are man-made, and not based in Dino oil, no matter how pure. Ultimately, synthetics are no slipperier, they simply hold up better as a base oil and it is the additives that controls the wear and keep things clean.

Additive packages in synthetics are no different than what we are calling Dino oil. Look at a virgin (unused) oil analysis or used oil analysis and the additive packages contain the same exact stuff. It's true. If they were slipperier, the wear numbers would be lower for synthetic and that is simply not the case, additives control wear.

In our older bikes that call for a relatively short oil change interval, the added durability of synthetic is lost in most respects, so changing todays Dino oil at recommended intervals makes great sense for all the protection these bikes need.

In the 80SG, 75w-90 Mobil 1 has been in the MD/FD since just before the Durango Rally in 2011, 4052 miles. Just about time for a change. Will report any undue particulates when I change before the July Colorado Rally.

[motoman]

75-140w RoyalPurple as opposed to coventional EP80-90w caused the diff. to run noticably cooler, can't say for the middle drive as that whole engine case is hot as a pistol anyways. Also, there is no longer a middle drive/final drive whine. Both instances mean less friction equals less wear on already aging metal.

[Bonz]

That's good to know, Motoman! I recall you sharing that story and am going to put 75w-140 in the SG at the next change. No difference in low temp flow, but better protection at the extreme high end.