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Discussion Starter #1
First there is this issue of fork oil.
I have never, ever, worked on forks, so I ckeck out the anti-dive on this and it requires I drain the oil. Looked like a good quality 10w to me. What exactly is fork oil, and why is the proper weight so important?

Second, The XVZ is the tedious of all machines on two wheels, to work on.
Am I missing a better eye, or a system they made to simplify all the stacked on components? The aftermarket manual I have, does not help much as per the types of screws a nd bolts that hold the plastic to the plastic, and the style of fastener that holds the frames together so I am guessing, adjusting and seem to making a good ole general mess of things.

Tell you, there is a fairing on a little plastic innerfariing that is bolted to the subframe which is bolted to the main frame....the hoods(?) that hold the electronic and ride components, are fastened american style to the upper arm rest style fairng holes, and it is all very heavy for the plastic they used.
So heavy in fact, that the repair I did with epoxy on the right speaker holder, broke loose the second I tried to move it.

Computer brains like mine, dream of the mainframe... so I suppose my sloth might be due to secondary superflouos subject(SSS) invasion.
 

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Fork oil not only lubricates the sliding parts, it provides the resistance to movement that damps out the bouncing springs. The weight of the oil determines how soft or firm the shock absorbing nature of the forks will be - thin oil, more compliance to bumps, but more bounce from the springs, thick oil makes the shock stiffer, so a harsher ride, but, up to a point, more control. If you think the forks are soft and floaty with your chosen weight, you can use, or mix in, a thicker weight oil. One other feature of fork oil is that it is made to resist the shearing that would break apart motor oil, making it thinner as time goes by; this is why automatic transmission fluid was the standard for forks 'back in the day'. Lastly, the weight of fork oil isn't as controlled as engine oils, so one brand 10W could be as thick as another brands 15W, because the defined ranges overlap that much. You just have to choose one, ride, decide if that's the ride you need, and be prepared to change it.
 

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Discussion Starter #3
examining fork oil...

So motoroil is not really a good fork oil due to its strange ability to sheer as it ages.

I have looked for a 10w sae oil to put in there, and all I can find is 10w-30's 40s 5x-20s 30s and heavier.
The Yamaha shop sells fork oil, Is it imperative that I use their high priced oil in the special anti-dive forks?
The manual I have says 10w so I am assuming a good quality 10w-30 would work.
 

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Retired twice: Navy and as a govt contractor
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You can buy it online. I went to a 15wt in mine
 

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Or, you can use ATF, as much if it is ~10W.
 
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