Moly or not to moly, that is the question...

Haven't had too much to blog about, I've mostly been doing chores around the house and staying inside on these hot smoky days. You don't need a weather man, with forest fires all over the state, it doesn't matter which way the wind blows, we get smoke now. So other than cutting up, splitting and stacking wood, I've been staying in the nice, cool garage working on the Moto Guzzis.

One of the maintenance chores on the Guzzi's is to change the oil (gear lube) in the differential, or rear drive as it's called the manuals. The problem is there's not the same listing of lubricants and capacities in the different manuals I have. So I checked with one of the Guzzi forums I follow and as luck would have it, there was a recent posting about this same topic. And typical of most forums, there was a split opinion, with people lining up on both sides to add their  voice on whether or not to add moly to the gear lube. Now moly (or molybdenum disulfide) was an additive used to reduce friction in high speed gears back in the day, but is not so common today. The consensus in the group was that moly is no longer needed with the current, high tech gear lubricants. Either they'd talk about how great their super high tech lubricant works in their bike or cite other bikes, like BMW, that they rode and never used moly. But of course there also were the stalwarts that said "if it's called for in the manual, then use it."  Fortunately, for me at least, someone posted an excerpt from Guzziology, the bible of all Guzzi mechanics, that not only called for moly, but listed the amounts to use in each model. So that was good enough for me, all I had to do was getter done.

Now draining the lube from the 650 was no problem, a 17mm nut that came loose without any trouble and the oil dumped down the drain I'd made into the pan with no spills, But 850, that was another story. While the manual said to remove the drain plug to dump the oil, a close inspection, that required a mirror to see underneath the rear drive, showed a ribbed cover with six hex head bolts. Apparently, it has a sump that requires removal of the bottom plate to drain. So I spent the next hour or so, lying on the garage floor trying to get a wrench on the nuts that I couldn't really see, then carefully removing them without stripping or breaking the bolts. Of course the gasket was glued in and tore apart, so had to scrape it off both the differential and the plate. Which means I'll have to order a new gasket before adding the new lube. 

Here's the bottom plate that goes on the rear drive. Why they didn't put a drain plug in it is beyond my comprenshion.

But I did get the 650 done, though I apparently added too much lube at first, so when I switched to adding the moly, the lube started running out of the level plug. Oops, now did the proportion of moly to gear lube get screwed up, or is it close enough to not need a do over? Like most things, I suppose it'll work out, one way or the other.