XS650D Ignition Timing Stuck

From your video, it appears you have a '77 model? If the carbs are stock, stock needle clip setting would be in the middle #3 slot. You shouldn't need to move it from there if you have no mods or haven't changed any of the other jets. But, maybe someone before you changed stuff? Here's a chart I made up showing the stock jet sizes .....

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Compare what sizes you've got to what should be in there. Also compare the needle number. I say this because there are aftermarket rebuild kits out there that come with the wrong size jets and the wrong needle. If someone put one of those kits in, your carbs could be way out of whack.
 
Alright. Here is what Ive got.

Previous owner replaced carbs with bs38's from a 68/69 complete with new style slides and all the appropriate jetting, needles, etc.

The needle was set to the wrong position originally so now I have set it back to the stock position.

The issue of consistent firing of right cylinder still persists. It is constantly stumbling while my left cylinder is running strong as can be. Idles smooth still and appears to be in no danger of dying. took it out for a good spin and there was no backfiring. just feels underpowered due to right cylinder not combusting consistently. This occurred after setting cam chain tension, valve clearance, points gap, ignition timing, and carb tear down. I feel like I just knocked something out of whack.

Here is what I have done:
  • gapped and swapped plugs after cleaning them well (they were black from running too rich) with no change. left cylinder still super strong.
  • Pulled plug and held to engine block to test spark while engine ran. I get spark consistently but location of arch jumps around on plug end and does not look as clean as spark on other cylinder side. I know my points are pretty worn and have ordered replacements. Trying to continue troubleshooting until arrival of parts.
  • refreshed carbs. pulled all jets, needle, etc and cleaned with carb cleaner. Reminder that these carbs were rebuilt a season or two ago and appear to be really clean inside.
  • Checked for intake leaks. there are none.
  • sprayed small amount of carb cleaner into air filter to check if engine was running lean, engine got bogged down. don't think it running lean.
  • air fuel mix screw is adjusted appropriately with no change with live adjustment.
  • Adjusted ignition timing with engine running by ear to try and get cylinder to fire consistently. don't think it has to do with timing. fully retarded and fully advanced on bracket with no fix. was able to improve it though.
  • I know its a wasted spark system so I swapped spark wires and wasn't able to start the bike. but honestly did that while I was running out the door for work. will check again. for all I know I left the kill switch off, hahah.
  • spark plug hole thumb test notes no noticeable difference in compression, hahah. will correctly test with rental compression tester to make sure there is no mechanical issue. Remember, this bike did not have this issue 2 weeks ago and there was no incident to lead me to believe something happened.

Here is what I am going to do next:
  • Check coils by swapping sides
  • clean all connections and switches (kill switch, ignition, etc.)
  • Trim spark plug wires to expose fresh wire.
  • Replace points when they arrive
Any more thoughts guys??
 
The points ignition system isn't a wasted spark type. Left points and coil must fire the left cylinder, right points and coil the right cylinder. You can't just swap the plug wires side to side or the bike won't run, as you discovered. To try the coils on different cylinders, you will need to swap the points wire connections to them and then switch the plug wires side to side.
 
The points ignition system isn't a wasted spark type. Left points and coil must fire the left cylinder, right points and coil the right cylinder. You can't just swap the plug wires side to side or the bike won't run, as you discovered. To try the coils on different cylinders, you will need to swap the points wire connections to them and then switch the plug wires side to side.

When using my test light during ignition timing the light would flash for both set of points intermittently. don't feel like it was due to contact with other components. connected test light alligator clip directly to points wire connection bolt.
 
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