Main jet blockage or a tear in the diaphragm.
For those servicing the Mikuni BDS26 (a double-carburetor setup often found on models like the Hyosung GV250), a critical feature within official service documentation is the Detailed Component Specification Table mikuni bds26 service manual
Hand-tighten the Pilot and Main jets. Do not overtighten brass into the aluminum body. Main jet blockage or a tear in the diaphragm
Use a flathead screwdriver to remove the Main Jet and the Pilot Jet. The Pilot Jet is often recessed in a deep hole—ensure your screwdriver fits perfectly to avoid stripping the brass. Step 2: Deep Cleaning Use a flathead screwdriver to remove the Main
. Maintaining these requires precise specifications for float height and jetting to ensure smooth throttle response and proper air-fuel mixtures. Technical Specifications According to service data for the Hyosung GV250 Yamaha XJ600 , standard settings are as follows: Specification (GV250) Specification (XJ600 USA) Idle Speed 1,450 – 1,550 RPM 1,200 – 1,300 RPM Float Height 6.2 – 8.2 mm Fuel Level (Wet) 4.0 – 6.0 mm below gasket line #90 (Front) / #87.5 (Rear) Jet Needle 2nd groove Fixed/Non-adjustable
Most stories start with a bike that only runs with the choke on or dies at idle—classic signs of clogged pilot jets