86 750F clutch fluid leak lever travel excessive

[greenyogi8]

Hi Everyone,

I am new to the site and just found out about vfrworld while looking online for some repair help.

I must admit that I joined in the hopes I can find some repair suggestions.

After going about 5 years w/o a bike, I just bought an '86 750F model with only 19K. It's in very good shape - all original, even the exhaust! I put on new tires (Dunlop stock sizes), had the shop do an overall check and test drive and have ridden about 600 miles since.

I just lost clutch pressure - there is wayyy too much lever movement before clutch engages, and when it does, it seems like it is all or nothing - not gradual like it is supposed to be. This happened last night. There was a little smoke from the area of the front sprocket and only about 4-5 drops of fluid made it to the ground. Has anyne had similar problems or does anyone have any ideas? I know that I have to find and repair the leak, but is this a known problem with VFRs like the rectifier-type of known issue?

Any help is appreciated!!
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[masonv45]

This is not a known issue. Open your MC and verify it is full. Then remove the slave cylinder and verify no brake fluid is getting past the seals. You will see crystallized brake fluid in the orifice. if you are leaking.

Remove the slave cylinder push-rod, clean it, lube it, and re-insert back into engine.

My guess is, your slave cylinder needs to be rebuilt.

[hawkman]

Mine did the samething a few years ago, just a leaking seal in the slave cylinder. It's an easy fix. Just make sure you do not let it leak onto the lower fairing. Mine did and I ended up with a BIG crack.

[greenyogi8]

I really appreciate the comments and suggestions. I'll check it out further tonight when I get out of work. Thanks to guys I'll have a starting point and I'll know what to check first.

I will post the results ASAP.

[greenyogi8]

Thanks Mason and Hawkman. Slave cylinder needs a rebuild - I don't think the fluid had ever been changed. There was a lot of dark gray gunk/sediment in the system. It also looks like the inside of the slave cylinder has been etched or very lightly corroded a bit from the old brake fluid. I was going to use a 00 or 000 fine steel wool to clean it up a bit, being careful not to take away too much material. $22 for parts for a rebuild or $97 for a complete ass'y? I'll try the rebuild!!

[Chris71Mach1]

couldja post up and let us know the parts you ordered for the rebuild and what all you did during the rebuild process? it sounds like this is something that a number of these bikes could suffer, and for 22 bucks, id be willing to rebuild mine too just as preventative maintenence.

[squirrelman]

be sure to refer to the Honda service manual, as the slave cylinder has a specific order for tightening the bolts, and don't over torque. if the gasket gets torn on removal, replace it....

[greenyogi8]

Sorry for not replying sooner - I've been out ridin' all over!! Thanks for all of your posts on this subject. I referred to the Honda repair manual (which arrived with my parts, luckily) and you're right - bolt tightening order and torque specs are detailed nicely. I also had the dreaded sludge in my system. Now my '86 shifts smoothly and precisely - just like a Honda! Brake fluid next...

Anyone have a suggestion on a brake bleeder device/tool that will make it easier for someone with only two hands to do fluid draining/bleeding for clutch/brakes more easily?

[masonv45]

This may help: Clutch - SabMagFAQ

[greenyogi8]

I ordered five new parts - a new cup gasket (this is ta rubber seal that is on the O.D of the piston inside the slave cylinder), a new small gasket (this small rubber gasket is located on the I.D. of the piston), a new spring, and two new 'paper' gaskets: one mounts between the slave cylinder and the shifter cover, and the other one mounts between the shifter cover and the motor.

Due to the time between this fluid change and the last one (who knows what decade THAT was), quite a bit of sludge had built up in the system, evidenced from the beginning by dark deposits in the MC. Bleeding took a little longer than normal to make sure that none of this sludge remained after flushing the old fluid out using a drain hose on the bleed screw of the slave cylinder.

After carefully covering all exposed painted and plastic surfaces with clean towels, I took the cover off the MC and carefully soaked up as much of the fluid as I could with a new piece of kitchen sponge, making sure not to drip brake fluid anywhere. The sludge I wiped up with paper towel. What ever was left I got rid of with a Q-tip an a toothpick, being careful to keep the dirt away from the drain hole in the MC. Then I filled with fresh fluid from a newly opened can of DOT4 fluid, replaced the cover and did The Old Bleeding Process, using about 5 -6 oz. of fluid to REALLY flush the system. I had to open the MC and add fluid three times before I was satisfied with the clarity of the fluid that was coming out of the bleeder screw. I wanted to leave nothing to chance and make sure that all of the old, conrtaminated fluid had been removed. Then, I cleaned everything up, went on a short road test around the neighborhood with about 40 shifts then checked the fluid level. It needed only about 1/2 oz. of fluid to top it off properly. No leaks and like new clutch operation since.

I hope this helps others who may need clutch system maintenance. If you have the means, I highly recommend getting a Honda Repair Manual. It eliminates guesswork. $36 is cheap insurance - get the manual!!