General
The clutch is hydraulically actuated. Squeezing the left hand lever actuates the clutch master cylinder applying hydraulic pressure through the clutch fluid line to the secondary clutch actuator. The secondary actuator acts on the clutch pressure plate compressing the clutch springs and disengaging the clutch.
The Hydraulic Vacuum Assist (HVA) slipper action clutch uses engine vacuum to boost clutch lever action. The slipper action reduces undesired engine braking when the engine is downshifted at speed.
Checking Fluid Level
Refer to Maintenance Scheduling → Regular Service Intervals: Buell Models → Regular Service Intervals: 2010 Buell 1125 Models . Check the fluid level as follows:
1. Stand the motorcycle upright (not leaning on the sidestand) on a level surface, turn handlebar so the clutch master cylinder reservoir is level.
2. Verify the fluid level in the sight gauge on the fluid reservoir.
3. If the fluid level is at or below the LOWER line, rotate the front forks to access the fluid reservoir and remove the cover, stiffener and diaphragm.
4. Inspect the cover, stiffener and diaphragm for damage. Replace the diaphragm if necessary.
NOTICE
DOT 4 hydraulic brake fluid is used in the hydraulic clutch. Do not use other types of fluids as they are not compatible and could cause equipment damage. (00353b)
NOTICE
Do not allow dirt or debris to enter the master cylinder reservoir. Dirt or debris in the reservoir can cause improper operation and equipment damage. (00205c)
WARNING
Contact with DOT 4 brake fluid can have serious health effects. Failure to wear proper skin and eye protection could result in death or serious injury.
  • If inhaled: Keep calm, remove to fresh air, seek medical attention.
  • If on skin: Remove contaminated clothing. Rinse skin immediately with plenty of water for 15-20 minutes. If irritation develops, seek medical attention.
  • If in eyes: Wash affected eyes for at least 15 minutes under running water with eye lids held open. If irritation develops, seek medical attention.
  • If swallowed: Rinse mouth and then drink plenty of water. Do not induce vomiting. Contact Poison Control. Immediate medical attention required.
  • See Safety Data Sheet (SDS) for more details available at sds.harley-davidson.com
(00240e)
NOTICE
DOT 4 brake fluid will damage painted and body panel surfaces it comes in contact with. Always use caution and protect surfaces from spills whenever brake work is performed. Failure to comply can result in cosmetic damage. (00239c)
5. Add D.O.T. 4 BRAKE FLUID (Part No. 99953-99A) until the level is above the LOWER line.
NOTE
Do not overfill the clutch master cylinder reservoir. Leave sufficient volume in the reservoir to accommodate the rise in fluid level as the clutch friction discs wear.
6. Carefully place the diaphragm, stiffener and cover on the master cylinder reservoir and secure with the cover screws.
7. Tighten the screws to 1–1.5 N·m (9–13 in-lbs).