Full synth oil in the 4t?

[talindsay]

So I've run nothing but full synth oil in everything I own since 2005, when I went to the trouble to get myself informed on what ester oils really are realized how incredibly stupid it is to knowingly push clay around the inside of an engine when synthetics exist.

I've been assuming I'd run a full-synth motorcycle oil in the Stella 4t as well - probably Mobil 1 because that's what I use in everything else right now, but maybe Motul if I couldn't find a wet clutch oil of the right weight from Mobil.

But my local shop - a very respectable and knowledgeable shop, Scooterville in Minneapolis - tells me that they don't recommend synthetics in the 4t Stellas because of clutch-slippage issues. Now, knowing a bit about oils I understand that one should *NEVER* run automotive oil in a wet clutch setup because of this very problem, but I would assume a good wet clutch motorcycle oil should be as good for my Stella as it is for my Bonneville (also a wet clutch). But then, I've rebuilt Stella engines enough to know that the Stella's clutch *is* pretty weak and crappy. Is it really so weak that a synthetic motorcycle oil can make it slip?

Does anybody here run high-quality synthetic motorcycle oil certified for wet clutch operation in their Stella? Have you had trouble? I'm prone to trust my local shop, but on the other hand it just seems kind of hard to believe.

[Robbie]

The only synthetic oil I've ever been comfortable with in my bikes is Golden Spectro.
Although a claimed synthetic designed for wet clutch systems, I don't know if it is esther based.

What I do know is it can make a crummy shifting trans into a nice shifting trans in about 100 miles.
I pressed Mobil some years back about using their product (Mobil 1 extended life is the esther based version) in a wet clutch environment and the final answer was it had never been tested in that environment.
However, we all know that the zinc (short version of a really long word) additive is a component that reduces the shearing effects that occur in the gearbox and Mobil 1 as well as the rest of the automotive oils, had to just about eliminate the zinc.
This, due to the potental of catalyst damage because of oil vapors drawn through the PCV system.

In summation, all my cars/trucks run Mobil 1 extended life and all my four stroke bikes run Golden Spectro......this since 1973.....so, obviously I am satisfied.

Rob

[Scalpel]

I switched to full synthetic right around my first service at 400-500 miles, and haven't noticed any problems. I'm running Top 1 Evolution Moto 10W-40, which is a little pricey but is specifically designed for high-performance motorcycles and wet clutches. Apparently a lot of the standard synthetic oil for cars cause huge slippage issues with wet clutches on bikes, so you really want to look for motorcycle-specific synthetics.

I'll make sure to post again if 1000 miles from now the engine explodes or something, but so far it's been smooth sailing with the Top 1 synthetic.

[Spiffy]

I'm running AMSOIL in my 4t and my clutch is slipping...

but I don't blame the oil... their web site says it's ok for wet-clutch...

I blame the 90° heat and steep hill trying to push my sidecar up it... so really I think it was the extra strain on the sidecar that made the clutch start slipping... I've got almost 9000 miles on it...

now I just need to find a decent after-market clutch...

[JohnKiniston]

With the weight the Dipstick wants for the 4T I'm running Motoul, It was one of the two oils I found in the correct weight and I decided to go with it over what Pep-boys was selling.

I'll check the bottle when I get home to see which one it is and if it's synthetic.

I've been using the Motoul Transoil in my 2T gearboxes since my first one.

[kamuela5]

I've been running Lucas full syn in my 4T since 500 miles. Now at 2000 miles and no slippage. The shifting actually sounds quieter. It's what I put in my dirt bike as well.