Why Does My Clutch Drag?

Tech Q&A: A New Slave Cylinder and Master Rebuild Fails To Solve a Shifting Problem

Clutch systems are often harder to flush and bleed than brake systems because the clutch works against spring pressure and doesn’t provide solid resistance like brakes.©Motorcyclist

Q. I have 27,000 miles on my bike, and a couple of months ago I started experiencing a shifting problem. The clutch drags so much I can't find neutral or even start the bike in gear without it jumping. I hadn't ridden it since last summer, and the clutch fluid probably should have been changed a couple of years ago because, when I checked it, it was dark and had particles in it. Also, I found moisture and rust in the master and slave cylinders.

I got a new slave cylinder and a master-cylinder repair kit, along with a braided-steel hydraulic line. Before installing the slave I filled it with fluid and made sure the piston moved easily. I filled the rebuilt master and used it to fill the line, pumping the air out of the system and closing the bleeder while holding the lever down. But the clutch still drags. What did I miss?

Dale A. Goss
Vicksburg, MS

Got tech questions that need ANSWERS? Email us at mcmail@bonniercorp.com.

A. Clutch systems are often harder to flush and bleed than brake systems because the clutch works against spring pressure and doesn't provide solid resistance like brakes. First, bleed the master cylinder by loosening the banjo bolt that secures the line while pulling the lever (you'll hear air or see bubbles coming out) and then tightening the banjo bolt. Repeat this until no air comes out, making sure to refill the reservoir when the fluid level drops—it's much smaller than a front-brake master, so be careful that you don't run it dry. If you do, you'll have to start over. Then bleed the slave cylinder using the bleeder screw (as shown above).

Make sure you wrap a rag around the banjo bolt to keep the fluid from dripping on painted surfaces and plastic parts. It also helps to put the bike on the centerstand or track stand (or prop it upright) to eliminate high spots in the slave cylinder where air can be trapped. If the clutch still drags, gain access to the pressure plate and see if the actuator is moving it far enough. If everything in the actuating system, from the master through the slave to any pushrods or other hardware, seems to be doing its job but the clutch still drags, it’s time for a deeper inspection of the clutch and, probably, new plates.