gear oil?

[tpi]

Thanks Robber for the clear detailed information and the pictures.

If someone just stumbled onto this thread I'd recommend reading all of Robber57's posts on the forum, they're very informative and interesting.

[tpi]

I'm the second owner of the scooter, do not know its service history. Bought it with about 1000 miles and its close to 2000 miles now.

Changed the gear oil today. It was pink and fairly light oil. No sulfur smell, very mild smelling. It was clearly less viscous than 90 weight gear lube.

Put in the Redline 70W80, which is also pink. The redline also has no sulfur smell, but definitely stronger in odor than what came ouit.

The Redlline container doesn't have a spout so I injected the new lube with kitchen flavor injector.

You can see the old oil in the glass container. It looks darker in the pic than actuality. I thought it looked pretty good with no debris or other evidence of a hard life.

[southerncannuck]

What is the problem with synthetic gear lube? I changed the gear oil today and used Lucas 75w90 synthetic. I thought I was doing a good thing.

[robber57]

Synthetic gear oil usually contains a lot of additives to stabilize the viscosity index, these additives are solvent like and may eat the seals , cause them to swell or dissolve the plasticizer in the elastomer after which the elastomer of the seal becomes brittle ,forms cracks and start to leak.
Its like soaking the seal in paint thinner.

Its a problem which also occurred with the first generations of synthetic motoroils but in motoroil this problem has been mostly solved.
In gear oil this problem is more difficult to solve although latest generation gear oil may not have this problem anymore.

However: the use of synthetic gear oil in a normal (non race)application is only beneficial on one or two points: increased interval for changing the oil and a more "flat" viscosity index meaning the oil stays better on the same level of viscosity regardless of temperature.
Point one: changing the gear oil is really not more then 3 minutes of work and one liter of oil will give you about 5 oil replacements so also on the financial side changing the gear oil is of almost no impact.
Cost and effort are so low that i change the gear oil at the same interval as motoroil.
Point two: a better viscosity index; the gearbox only has 4 gear wheels on two axles and both axles run on ball bearings.
The effect of a better viscosity index in such a small gearbox is negligibly, its not a high tech 6 speed slipper clutch gearbox and i assume you dont drive anywhere near the pole circle/Antarctica.
Above 15 degrees C the problem of thick gear oil is almost non existing

So why take the risk of broken seals?....

Throwing the bottle in the garbage is a bit over the top but next bottle you buy you may want to reconsider the perceived holy grail of synthetic oil, its not all that fabulous,there are drawbacks to synthetic motoroil.

[southerncannuck]

Boy do I feel like an idiot! My scooter is 2 years old and I did the differential oil change. What came out was closer to Kool Aid than oil. I initially used synthetic, but at the suggestion of Robber57 I changed it again to dinosaur oil. What I learned is that it is very easy and inexpensive, and should be done at every oil change. Now, onward to the radiator and brake fluid.

[tpi]

No leakage or seal problems on SH150 to date. It is bone dry. Synthetic gear lube has been common for at least a decade. My '99 Ford pickup came with synthetic gear oil from factory, so does my '11 Tundra. In my opinion it would be extremely rare for modern seals to be incompatible with synthetic fluids from reputable vendor. Especially well regarded mfg. such as Honda. I wouldn't think of draining the synthetic gear lube out of my scooter. The Redline fluid I used contains no VI improver.

[robber57]

Brake fluid: beware of silicone based DOT5 , its use is restricted to calipers with seals that can stand silicone based fluid and these are not found on Japanese motorcycles but on Harley Davidson.
A normal DOT3 or better DOT4 is perfect.

Coolant: use either ready to use coolant or selfmix coolant+demi water(1:1), there are longlife versions which last (a bit)longer.
The coolant should not have silicate based corrosion inhibitors and should be mixed (if necessary) with distiled water, using tap water may cause aluminium parts to corrode.

Note there is a difference between antifreeze and coolant, antifreeze is just what it says and nothing more, coolant is a total solution-it contains the antifreeze part and rust inhibitors+lubricating fluids to lubricate the pump seal.