Middle drive or not

[DGXSER]

So, as I was tearing down the project bike, I found the rubber boot around the U Joint was wet with an oily fluid. Now, the entire length of the axel tube was lined with grease, but it was not liquidy.

When I pulled the swing arm and removed the boot, I sat it on end. There was a puddle the size of a couple golf balls under it. I am thinking I have a leaky seal at the rear outlet of the Middle Drive.

Now, I still have the Middle Drive from ole Thunderstruck (the SH I wrecked in 2010). So I may just swap it in to this bike.

[BA80]

Was the middle drive still full?

[DGXSER]

I have not checked it Greg. And honestly, having sat for 6 years or so, I am not certain it was full when it was parked.

[Rasputin]

Just a thought but could it maybe be just moisture and grease mix dripping on the floor. If the drive shaft was way over lubed, might be something in that fact to check out before the middle drive leak. Mostly thinking out loud here.

[BA80]

I have not checked it Greg. And honestly, having sat for 6 years or so, I am not certain it was full when it was parked.

Just from experience, if you think it's leaking check the oil. If it's low a leak is a good possibility, if it's not low it probably isn't leaking.

Most every boot I've removed there was gook in there.

[bikerphil]

If you do decide to change the seal, it is a Yamaha specific seal, odd looking one. My MD's seep a little bit and it does make a mess inside there with the grease. Synthetic gear oil may make it leak even worse.

[CaptonZap]

If the oil that drained has the typical hypoid sulfur smell, (assuming that was what you had in it), than the seal would be a suspect.
If it is just oil, grease will separate after many idle years and temperature cycles, and leave a whipped wax like residue where the grease was, and an oil slick at the bottom of the containment.

CZ

[jetmechmarty]

+1. My boot was clean upon recent inspection. My middle drive leaks a little Royal Purple someplace. The best option is to replace the seal and/or the drive. If you choose to replace the drive, do it with new seals installed. Leaking synthetic or any other lube points to seal going away.

[trbig]

Regular grease or middle drive fluid... Should be able to tell just by the smell. That gear oil is some foul @#$&.. even when new, and gets worse with age.. Kinda like Greg.

[skids]

You might find that the seal has shrunken from sitting for so long (I think you said years). I would definately change the fluid and then get everything good and hot with a long ride and monitor the level of the drive oil carefully. It may stop its own seep.

[trbig]

I wonder if you can add any of that stuff that swells the seals and stops transmission leaks?

[BA80]

I would try what skids suggested first. That is if it's leaking at all.

A heat cycle or two can cure seeping seals.

[jetmechmarty]

I wonder if you can add any of that stuff that swells the seals and stops transmission leaks?

I'm a little surprised to see that suggestion come from you. How long does it take you to remove the middle drive? I expect you'd have it out in 20 minutes, working on the side of the road with sleet falling on you.

[BA80]

Look at that! He even carries his own personal orange cone.

[trbig]

I'm a little surprised to see that suggestion come from you. How long does it take you to remove the middle drive? I expect you'd have it out in 20 minutes, working on the side of the road with sleet falling on you.

Ya know.. That day sucked really bad. lol. But, I think back on it now and laugh. Those people at that truck stop and that town in general were some of the nicest folks I've met. They even put that cone up to keep the cars off me.

And no, I wouldn't add that stuff to mine. Just bought another middle drive off fleabay $20 delivered off a bike with less than 10k miles. Stock 1100 though, not the 750/850. Still cheaper to replace them than fix them. In another 30 years.. who knows. Hopefully I'm around to care about it. lol.