Is it worth rebuilding 500 M/C and S/Cs?

I helped my mom get a 500 from someone on one of the 500 lists. We got it for $500 and a trip from Me to NY and back. The guy was the second owner, and then sold it around his neighborhood. He said all it needed was the carbs fixed. Something about a broken part. I got it home, and started poking around. The first thing I discovered was that the wiring harness was all messed up. You would not believe what they plugged into where. Actually I was an airplane electrician and I'm pretty sure I've repressed the memory. Any way I was going to use the bike as in class room aid for MSF classes I wanted to teach. The lights and the clutch have to work, but it doesn't have to run. I got all the lights working, no prob. It involved robbing the parts bin from my VF's stripped street parts. But, then I went and squeezed the clutch lever. Nada. I took the cap off of the master cylinder and it looked like someone had soaked cus-cus in the brake fluid. I have made friends with the nice old lady next door, and may get to use her garage space to work on bikes this winter. So this morning I started digging around ebay thinking I'd find a new clutch master cylinder and slave cylinder for cheap. Wrong! But I did find rebuild kits for both. Is it worth it to just rebuild these? I have tried and tried to flush the crap out of the clutch M/C but to no use it won't pump. I am worried the slave cylinder has the same issue or is contaminated. Does anyone have experience with this? It sounds like there are a lot of 500 people on here that I can get info from.

Thanks,
Rich

 

Rebuilding the master cylinders is just fine. In fact, just a simple cleaning and new fluid might be all you need. I'd start with that and see what happens. You might be surprised at the results. Only replace/repair/rebuild what you have to and leave the rest alone!

 

Well, I've try flushing it out, so you must be referring to taking it apart and cleaning it?

Thanks,
Rich

 

No telling how long this thread might grow b4 you have a dependable, running bike........:wink:

When buying, never listen to the guy who says "it just needs......." cuz 90% of the time he's lying or ignorant.

Get rid of all the original fluid in brake and clutch systems and get new seal kits.

 

Funny thing about that, the PO e-mailed me back in February wanting to know how the bike turned out. I told him. It seemed he genuinely felt bad. Not bad enough to refund some of the money though. It should actually work out because I have a lot of parts my VF500F race/track project bike has and can donate. I knew it'd a project either way.

But who should I listen too? Jamie who has years of R&D, experience, and love for the bike, OR some guy who thinks 700s are cool?

Later,
Rich

 

Jamie, of course. He's an engineer !!!

 

Yeah, just flushing with clean fluid doesn't always do it. Plus you can push crap down into the calipers that way too. I'd pull the piston out and clean everything with brake cleaner. Might not be a bad idea to clean the calipers too.

One thing to keep in mind is that bleeding a bone-dry system is difficult. A vacuum bleeder like a MityVac is a god send for tasks like that.

 

Yes, I have experience with the "cus-cus" syndrome :frown:. Yes, it will be in the Slave cylinder as well . Yes, you are better off getting a good used clutch and slave cylinder set.

The "cus-cus" is a product of a chemical reaction that takes place when the bike is left sitting for many years. I do not know how the reaction happens but it involves the metal on the walls of the cylinders . You will have to scrape all the "cus-cus" out of the master and the slave and inspect. My guess is that the wall of the master and slave, both will be damaged. Because the master had such a small a diameter you will not be able to find a hone that is able to fit inside the master cylinder. But the pitting will be too deep anyway to use a hone to any good effect. You will have to replace the master and probably the slave as well.

As for bleeding the d..m clutch, its a matter of patience and dogged determination.. The problem is that air gets trapped along the line that leads frome the master cylinder down to the slave and it's a bear to get it out of the line. I have tried vacuum pumps without success and have had to finally go back to the old pump with the bleeder closed in the hope that the air moves down the line closer to the slave. Open the bleeder with the master held almost closed. There is a reason for not holding the master against the hand grip but I can't recall what it is at this exact moment. But when you open the bleeder have a spacer between the left grip and the clutch handle that keeps the handle about 1/8 to 3/16 in. from contacting the grip. Don't give up. It takes persistence, whether you are using the old tried and true hand pumpup method or the vacuum pump.

You will feel the resistance slowly coming back into the master cylinder. When you first feel the resistance coming back you will think its just a dream. Its not. It happens very gradually. It might take an hour or more of persistent pumping, holding and releasing the bleeder after you feel the resistence coming back into the line :frown:. Don't allow the bleeder to remain open long and don't open the bleeder more than is necessary to allow the pressure to come off before closing it. The whole process is a mess. Be prepared to clean up spilt fluid from the handle bars on down to the floor :frown:.

Good luck finding replacement cylinders. Your brake cylinder will also probably have "cus-cus". Take a good look inside the cylinders for errosion of the walls. The clutch slave is large enough to get your fingers into and to polish down, but you decide if you want to chance it leaking after you spend a day or longer getting the air out of the clutch line. And have a nice day:smile:.

 

Once again, making us look bad with the long responses DKC!

I've found the clutch side to be way easier than the brakes. Once you start to get a little pressure on the lever it goes pretty smoothly. Just work the lever about 50 times (it doesn't take very long) and you are all set. This is because you are moving a lot higher volume of fluid in each stroke. The brakes, however, don't move hardly any fluid at all. You can pump until you are blue in the face and still not have anything. You need to build up some initial pressure in the lever to get things started, the trick is getting that initial pressure going. Tying the lever back against the bar overnight can help, but it's much easier to just use a MitiVac and be done with it!

 

All God's Chillin' Got MityVac's

Gittin' a mite touchy there Jamie?

The problem here is not the bleedin'. It's the "cus-cus" in the clutch master. It's dust. You can't just pour new fluid in the reservoir and start bleeding with "cus-cus" jamming up the line or the banjo fittings. You have to take the whole d..' system apart and clean the dust out. I've seen "cus-cus" only when it has gone all the way to powder. If there is some intermediate stage where some of the old hydraulic fluid is still in the form of a liquid and it has moist "cus-cus" floating or submerged as it erodes the wall of the cylinder, I haven't seen it. What I have seen is removing the plunger to find it full of cus-cus right out to the end of the master and into the banjo fitting, on bikes that have sat in garages or outside for 10+ years.

A common collateral effect when the brake master goes sour is that the brake pistons get jammed and the pistons "freeze" in the calipers causing the front (rear) disk(s) to lock tight. The cus-cus particulate fills up the space behind the pistons in the caliper and then it expands to lock up the brake. You think, "I'll just pull the clean out plugs on the calipers and relieve the pressure on the brake pistons." But when you pull the plugs there is no fluid in the caliper cylinders. What you get is a solid plug of cus-cus dust.

 

Here's a data point to consider. I picked up my 1986 VF500F about 4 weeks ago with absolutely no clutch. The master cylinder had no liquid left - just the slimy-looking cus-cus. I tried cleaning it out with a shop rag and added fluid, then bled, but couldn't get any pressure.

I bought the bike anyways and took it home. The next day I picked up a Mityvac, poured more fluid in, sucked it through with the Mityvac, and the clutch felt great after 5 minutes of work! 4 weeks later and about 50 miles, all is great.

Get the Mityvac (or borrow one) before you do anything drastic!

Dan
Western Chicago Suburbs

 

Cool posts!

Frist: I love how everyone has adopted my "cus-cus" term.

Second: DCK, when people say stuff like that to me I always reply, "Well if you didn't make it so easy." But I think Jamie was joking. Any way.

Since it's my Mom's bike, I'll take the time to tear it everything apart. I have not found "cus-cus" in the brakes yet, but I'll take them apart anyway. It may be a some time before I report in on this part of the adventure as I have yet to convince the sweet old lady next door to let me use her garage to work on bikes this winter. Wish me luck. In the mean time, Squirrelman feel free to drop in and spin yarn about the woe's of owning a VF.

 

If it's wet, you can save it yet, if it's dry, time to cry.

Hey, daeven,

If you actually had a case of the "cus-cus blues" and you were able to salvage the mess by mucking out the dirty reservoir then more power to you. I think you just had a very dirty reservoir and a lucky break with air in the line. But we can argue that point until the cows come home. It's a matter of what defines what constitutes "cus-cus". I tend to think of it as liquid that has magically turned to a white/cream/and sometimes black powder with little or no liquid in the mix. The "couse-couse" description is apt because this dried mess looks granular and has a mottled appearance not dissimilar to "couse couse" without any green chopped parsley or olive oil look to it. (sounds tasty don't it :tongue.

I never tried putting new fluid in the dried powder to see if the powder would go back into solution. But if you are game tell us the outcome the next time you do. I figured it was a big enough mess as it was and I wasn't going to add brake fluid to it as well.

 

I don't think there's any arguing going on - that's why I used the words "data point." I only added to the conversation to encourage anyone to not toss otherwise good parts until they try a vacuum pump. Sometime you get lucky, like I did!

Dan

 

Just messing with you bro!

You do, however, own the record for longest replies.

 

Well here's an update, I no longer have a garage to work in. The "sweet lady" next door is giving the space to her nephew to store his stuff in because he's moving back home with the folks. grrrrr. The next plan is to say screw it and get a storage unit and move the 500 into the spare room!

 

Oooh... that sucks. I imagine it gets even colder in Maine than it does here in Indiana.

 

Wait and see.

You don't know how much stuff that nephew has. He may not be able to fill a single garage with his stuff. There might be a silver lining here. Say the Nephew drops half a garage of stuff on Auntie. Then you only have to heat half a garage. YOu can stack the nephews stuff up next to the door to act as insulation and heat the recesses of the garage for your project, if she will be pursuaded to allow you to utilize the space that is not used.

Pursuasion could include crossing the old ladies palm with silver. She might prefer some income, even if it were nominal, to letting her nephew have the space for nothing.

Don't give up so easily. Remeber, you live next door and the nephew is going to live with his mother. You have the advantage of being there all the time. You need to find a strategy that will get her to allow you to use the space that the nephew does not utilize.:smile:
DKC