Johnny Boy
Member
Hello fellow Wingers. I have a 1980 1100i. I got it a couple of months ago. It starts, idles, revs clean to 5500 rpm, shifts, brakes and generally runs well. 27,000 miles on the clock. However when running hard through the gears it has a miss right at 5500 rpm.
I checked the fuel flow from the petcock and installed a new Napa fuel filter. I pulled the carbs and checked the float heights. They were right on at 15.5mm. Jets and related bits were removed and checked for blockage of the tiny side holes, all clean. Float needles and seats sealing well, not leaky. Mixture screws were set to 3.5 turns out. I reset them to 2.25 turns out. The slides on the top move clean and smooth up and down.
I put the carbs back on and did a carb sync. I have the Twinmax carb sync tool. Nothing changed, I still have the same miss.
I then went after the spark. I removed the coils and wires. One coil ohm tested bad, one tested good. I ordered a set of Caltric (?) coils off Amazon. They came with new wires. I am not running a radio or intercom so I removed the 5k ohm resister in the plug caps. I had some thick solid copper wire and cut pieces the same length as the small 5k ohm resisters. I put the wire pieces in place of the resisters. I then confirmed continuity through the wires and caps. The plugs are new NGKs.
I then took it for a test ride expecting no miss considering it had a bad coil and now has 2 new coils and non-resister caps. No luck, still a miss at 5500 rpm.
I then read about the vacuum ignition advance. I pulled the hose off carb #3 and applied vacuum to the hose (to the advance). I didn't hold the vacuum forever but it took a very long time for the needle to move a small amount. That looks like pretty good vacuum, right? Well, I tried running without that vacuum line attached. I capped the nipple on carb #3. Right from the start it missed bad and ran terrible. I pulled over and re-attached the vacuum advance hose to carb #3. It then ran good but with the original problem (5500 rpm miss).
Air filter is a new Emgo. The exhaust is not collapsed. Non-ethanol (not old) gas.
I'm stumped fellas. Can anybody help?
I checked the fuel flow from the petcock and installed a new Napa fuel filter. I pulled the carbs and checked the float heights. They were right on at 15.5mm. Jets and related bits were removed and checked for blockage of the tiny side holes, all clean. Float needles and seats sealing well, not leaky. Mixture screws were set to 3.5 turns out. I reset them to 2.25 turns out. The slides on the top move clean and smooth up and down.
I put the carbs back on and did a carb sync. I have the Twinmax carb sync tool. Nothing changed, I still have the same miss.
I then went after the spark. I removed the coils and wires. One coil ohm tested bad, one tested good. I ordered a set of Caltric (?) coils off Amazon. They came with new wires. I am not running a radio or intercom so I removed the 5k ohm resister in the plug caps. I had some thick solid copper wire and cut pieces the same length as the small 5k ohm resisters. I put the wire pieces in place of the resisters. I then confirmed continuity through the wires and caps. The plugs are new NGKs.
I then took it for a test ride expecting no miss considering it had a bad coil and now has 2 new coils and non-resister caps. No luck, still a miss at 5500 rpm.
I then read about the vacuum ignition advance. I pulled the hose off carb #3 and applied vacuum to the hose (to the advance). I didn't hold the vacuum forever but it took a very long time for the needle to move a small amount. That looks like pretty good vacuum, right? Well, I tried running without that vacuum line attached. I capped the nipple on carb #3. Right from the start it missed bad and ran terrible. I pulled over and re-attached the vacuum advance hose to carb #3. It then ran good but with the original problem (5500 rpm miss).
Air filter is a new Emgo. The exhaust is not collapsed. Non-ethanol (not old) gas.
I'm stumped fellas. Can anybody help?