Motorcycle Repair: 85 V65 Magna clutch problems, clutch slave cylinder, v65 magna

Question
Bill,  I got through my carb problem.  It only took my 2 attempts at pulling and cleaning the carbs to get it right.  Runs great.  Now I have a clutch issue.  For some reason the clutch would not engage.  The handle has no play and feels hard to pull in.  I figured since it is a hydraulic system that it must be a fluid issue.  I checked the level and it was low, possibly low enough to get air into system.  I figured bleeding the system could help.  I started bleeding the system and got carried away and let the fluid get very low letting in air for sure.  So, filled res up with fluid and started bleeding again but carefully this time.  I got the clutch working good.  I rode the bike for about 50 miles and no problems.  A few days lasted I rode the bike and about 10 miles into the ride the clutch started slipping and the handle again got hard to pull in with no play at all.  I again bleed the system and it started working good but again in about 10-15 miles of riding it did it again.  I am a bit confused.  What do you think?
Thanks, Bruce

Answer
Bruce, the clutch hydraulic system is not unlike the front brakes. There is a tiny bleed port in the floor of the master cylinder that allows backflow of fluid into the master cylinder. If it gets plugged up, the fluid becomes trapped in the line and holds pressure on the slave cylinder, which keeps the clutch from fully engaging. Be sure that that both small bleed holes are clear and clean.

Your clutch slave cylinder might also be hanging up due to an swelled up piston seal. After all these years, a rebuild of the master cylinder and clutch slave cylinder would be a good idea. Check your hydraulic hose condition, too. Replacing it with a braided steel line will help overall hydraulic performance.

Bill Silver