running crappy bendix carb,seems to be running rich, outside of idle adjust screw, no other adjustments are visible also exhaust seems to make a funny sound like popping at idle. any help would be great thanks 1971 stock, drag pipes
First you need to get a good overall picture of your rich condition. Your Bendix has a non-adjustable main jet. It also serves to hold the fuel bowl on. There are six different jet sizes to allow for tuning. You need to see if your (1) rich only at idle (worn or out of adjustment idle screw of high float level) (2) Too much accelerator pump shot causing rich mid range that clears out after initial throttle up. (move the roll pin in pump shaft down to lean out / up to richen) (3) you ar running rich fron mid to high range. (to big a main jet (go to next lower size main jet. /// To find out.. Will the bike idle steady without black smoke exiting the pipes? Can you adjust the idle with the advustment screw? If No check float level. - If yes -/// -Carefully remove the small screw & washer that attaches the accelerator pump to the throttle shaft, leave pump in the carb if it feels like it will stay, if not use a rubber plug or cork to block the hole off. Take a ride and see what it does. Does it run right now? if Yes-///- lean the accelerator pump out (iv'e seen them work best with the pump totally disconnected) If no-if the bike stumbles upon acceleration, hook the pump back up. -///- Find a streight strech of road about a mile long where you can safely stop and pull the spark plugs. Install new plugs. Run the bike in 3rd gear at a steady mid range rpm for about a mile then pull the clutch in and shut the bike off (with out going back to idle) pull the plugs and and see what color they are. If your rich they will be showing black coloring. if yes- your main jet IS too rich. Go to the next leaner jet and check again. It generaly takes longer for the plug to color if your running good (tan) 5 to 10 miles. Caution!! If the plug does Not color but stays White, your running Lean and can hurt the engine. If you need jets check jpcycles.com they list jet numbers and sizes and can supply them. I'm sorry this is SOOOOoooo long but hope it helps. The Bendix carb is a good carb and is available in a Adjustable Main Jet version also.