1984 vf1000f clutch problem

HOWDY,

I JUST PICKED UP A 1984 VF1000F. It had sat for a year or two in a covered environment so as I was doing a number of things to get her back on the road I checked the hydraulic clutch lever. Spongy and soft. Opened up the master cylinder and it was empty but for some Bantha poo sludge that was at the bottom of the master. I cleaned out the poo and flushed through the system with DOT4 until clear fluid was coming out at the hydraulic unit on the side of the engine case. The lever was really stiff and felt good (if you like a stiff clutch)

I went for a ride and as the engine heats up the clutch began to slip to the point I had to push it back the last block to the garage. I figured bad clutch, replace plates. Went through the clutch replaced the new cork disks, reviewed the steel plates and they were flat no warpage. so placed them back in. Didn't check any springs.

New oil and filter and fired her back up and same problem. Clutch starts slipping as if it is engaged. If it were my bmw r90s I would say that the clutch needed adjustment and that it was engaging all the time so as I accelerate the clutch slips. But that is a mechanical dry clutch and the vf1000f has a hydraulic system seems to need no adjustment.

This unit has the locknut on the clutch basket and I had to make my own tool which worked but I had a hard time securing the whole clutch basket to get enough purchase to torque down the nut. I finally got it to just click at 60ft/lbs as the manual said and everything went back together well (the snap ring was a little tight to get back in but it went.)

Not sure if I needed a touch more purchase on the locknut, or my springs are bad or there is some kind of adjustment to the clutch lever?

Any help would be much appreciated.

Cheers,

 

Want to bet? If your frictions were bad enough so the clutch slipped. Then I'll bet the steels are warped also. Did you check them on a machined flat surface or a piece of glass and use feeler gauges? All it takes is .010"-.020" and they are shot. Always replace friction and steels at the same time. There is also a big conical type washer that also applies pressure. If it flattens out some it's no good then. There are specs in the book for it it only takes a few thousands for that also.

Part number 14 here:Honda | Suzuki | Yamaha | Can-Am | Ski-Doo | Sea-Doo | Motorcycle | ATV | Scooter | Parts | Accessories

 

Thanks Grey,

I'll be tearing into it again.

I'm new to the VF's Do you have a solid parts source (preferably on the west coast) that you guys use? I don't really like going through dealers as they don't support the classic bikes. Much prefer to support someone like Jamie Daugherty who is specializing in our bikes.

Any resources would be helpful.

 

Thanks Grey,

I'll be tearing into it again.

I'm new to the VF's Do you have a solid parts source (preferably on the west coast) that you guys use? I don't really like going through dealers as they don't support the classic bikes. Much prefer to support someone like Jamie Daugherty who is specializing in our bikes.

Any resources would be helpful.

 

Did you make sure that you cleaned out the tiny orifice in the bottom of the master cylinder, sometimes it has a shiny metal cover plate over it? That is the return port and the clutch will not release if that orifice is clogged, with symptoms exactly such as you have described.

 

Hey Kenny,

GOOD CALL!

I popped open the master and found there was no shiny metal plate and the hole that you spoke of was plugged solid with Bantha Poo. I grabbed another metal flap from a vf1000r parts bike I have and placed it back in.

I removed the DOT 4 in the master and scraped the muck off the hole as best I could. I put a few drops of brake cleaner in the hole and dabbed it out with a towel. I got down to be able to clearly see the hole and blew compressed air around the master to blow out any remaining chunks. I filled it back up with DOT 4 and I'm off for a test ride.

Do you have any suggestions for cleaning it further? Do I need to run a solvent through the line?

Any suggestions?

Cheers,

 

Just got back from the ride. The initial clutch performance was better but degraded with time or heat of engine? It was slipping bad enough to have to coast/push the last block after a 10 minute ride.

Once it cools I start it up and it does well for a few minutes and then degrades quickly.

 

The master may still be clogged. Usually have to use a small piece of wire or guitar string to rod out that hole. The tiny shiney plate is not really needed except to keep fluid from squirting in your eye when you pull in the clutch with the master cover open.

Did you clean the slave cylinder? That same sludge is likely there also.

As the brake/clutch lines get old they can shred and slough off the interior rubber surface. The debris clogs the line and can act like a one-way valve--fluid flows down but won't make it back up. As temperature increases the pressure in the line increases and the slave piston moves to engage the clutch. You might be able to blow air thru the line from bottom to top to clear a blockage.

 

Thanks Kenny.

Looks like I have to pull the master and slave and do a full flush....

Maybe new lines.

Do you have a good source for OEM parts (master and slave kits?). Dealers these days don't support anything older than than their last undie change...

I'm new to VF's and looking for some good online resources.

I found Jamie Daugherty so my suspension is getting dialed.

Any links would be much appreciated.

Cheers

 

The place in my last post ships fast. I've used them the last few years. There's cheapcycleparts, bikebandit, and others.

 

Thanks Grey,

I missed that in your last post.

Will check them out.

Cheers

 

On a bike that old, i don't see why anyone would NOT replace springs when they had clutch problems..........?? With weak springs, even new plates could slip under high power.