Watery sludgy gear oil?

[Randomize]

Show them the vid and invite them over to see your new coffee machine.
I would keep changing it at every oil change even if you get it to run clear now. Sludge is tenacious as I found when I dropped the oil pan. If you haven't changed the fork oil yet be prepared for more of the same in there. Did I mention brake fluid ?

The fork was professionally straightened a few weeks ago. I'm not really sure what the process is for that but assume the oil is replaced at the same time?

Crossing my fingers on the brakes. We'll see.

[Brendan W]

The fork was professionally straightened a few weeks ago. I'm not really sure what the process is for that but assume the oil is replaced at the same time?

Crossing my fingers on the brakes. We'll see.

Assume nothing. Ask what they did. Professionally straightened could have been a squeeze on v blocks under a press. How did they get bent and how bent ? I don't think I could ever trust straightened forks.
Brake fluid needs changing every two years at least not only to keep the boiling point high but to flush out crud that sinks to the calipers and will look for every opportunity to block, corrode, jam, you name it. If it's darker than pale straw it needs changing.

[tkent02]

It needs changing anyway, because of the catastophic damage it can do if it's not.
It takes what, $5 and twenty minutes? Easy choice.

Brakes locking up out of the blue isn't funny.

[Randomize]

Assume nothing. Ask what they did. Professionally straightened could have been a squeeze on v blocks under a press. How did they get bent and how bent ? I don't think I could ever trust straightened forks.
Brake fluid needs changing every two years at least not only to keep the boiling point high but to flush out crud that sinks to the calipers and will look for every opportunity to block, corrode, jam, you name it. If it's darker than pale straw it needs changing.

The forks were 5 mm bent and yes, brakes are next on my list of things to change.

[Randomize]

An update: The top-shelf synthetic I put in it last night completely dissolved the sludge and came out a nice smooth chocolate milky texture. I ran some kerosene straight through it to knock the discolored oil out, then ran it through the gears with a belly full of kerosene and alcohol. Drained that, filled with oil and did the same thing, then drained and filled again. We'll see how she does.

[Randomize]

A follow-up for anyone who has a similar issue and finds this thread: Shifting is a little stiffer than it was before but works fine. I'm guessing the nasty oil was providing some extra friction for the synchros. It has a tendency to want to bounce off of first gear if it's still idling high from the choke but is fine once it warms up and the choke can be backed off.

[Randomize]

If you haven't changed the fork oil yet be prepared for more of the same in there. Did I mention brake fluid ?

Replaced fork oil and seals last night. It was dirty but not chunky or anything unusual like that. Rebuilding all three calipers and the front MC is up next.

[Brendan W]

Replaced fork oil and seals last night. It was dirty but not chunky or anything unusual like that. Rebuilding all three calipers and the front MC is up next.

Let me guess, a dark grey colour. A lot of it will be bits of ground spring and if the bike has sat for any time will be difficult to dislodge the last of it. I'd plan another oil change sooner than usual say at the next sump oil change.

[Steve]

So I cracked open the gear oil (the gear box, not the shaft)...

OK, the "gear box" does not have its own oil supply.

The shaft oil showed no signs of water or sludge.

The shaft itself has no oil.

I'm guessing the nasty oil was providing some extra friction for the synchros.

This would be a neat trick, because there are no synchros.



The oil that was draining in the video was from the "secondary drive". That is directly associated with the shaft drive. It only lubricates the right-angle gears between the transmission output and the shaft input.

Not sure what you are calling "shaft oil", as the shaft itself is dry. At the front, there is a flange ahead of the u-joint that bolts to the ouput of the secondary drive. At the rear, there are splines that slide into the input of the final drive.

.

[Randomize]

OK, the "gear box" does not have its own oil supply.

Yes, you're right. I had it my head that it was the gearbox but it's actually just the head of the shaft. The manual calls it "Gear Oil" so you can understand the confusion.

[Randomize]

Let me guess, a dark grey colour. A lot of it will be bits of ground spring and if the bike has sat for any time will be difficult to dislodge the last of it. I'd plan another oil change sooner than usual say at the next sump oil change.

Will do.

It was more brown than grey, actually. The springs and spacers were grimy but not worn. It wasn't until I flushed some ATF through that any grey came out.