Only running on one cylinder, please help out of ideas

[650hcs]

So I built me a cafe racer and when i finished I realized im only running on one cylinder. I have 150 compression, great spark, and fuel in the carbs. but when its running I can pull the left side spark plug wire and it still runs but when i put the plug back start up again and pull right side plug wire it dies wich I belive means its only running on one cylinder plus the exhaust on the left is just air not that hot comparred to thr right side. I checked the points and they look good and are at the right setting according to the manual. Does anyone have any ideas or is there something im just not seeing. please help, really want to ride. Thanks.

 

[retiredgentleman]

So I built me a cafe racer and when i finished I realized im only running on one cylinder. I have 150 compression, great spark, and fuel in the carbs. but when its running I can pull the left side spark plug wire and it still runs but when i put the plug back start up again and pull right side plug wire it dies wich I belive means its only running on one cylinder plus the exhaust on the left is just air not that hot comparred to thr right side. I checked the points and they look good and are at the right setting according to the manual. Does anyone have any ideas or is there something im just not seeing. please help, really want to ride. Thanks.

You could try swapping over the spark plug lead/caps from one side to the other to see if the problem follows.

Oil contamination on the one set of points??

Bad spark plug.............again try swapping?

One of the ignition coils could be faulty?

 

[leggers]

First off don't pull the plug wire off while running because you can damage the coil in the process. Always keep a plug on the end of the wire so it can put out spark. Ask my old coil why I know this.

Second, I had the same issue but the carbs were so horribly synced that one cylinder was not getting enough gas. Plug was wet so I assumed it was getting gas, but it needed more gas to fire. Sync those carbs!

Also check both floats on your carbs because float height will also affect firing.

 

[nicholauslee]

I'm not sure the solution, but I believe I'm having almost the same issue, except reverse.
It seems to run alright, and even seems to have decent get up and go, but my right cylinder is just pushing air, and I can pull the plug with no results. Even starts up just fine with one plug in it.
Let me know if you figure out the issue, and I'll do the same. As for now, the suggestions left so far were going to be my next steps.
Unfortunately, I just moved about 2 hours away from my parents house, where I keep my bike, so I only get to work on it for a couple hours every other weekend or so.

 

[Tron]

I had a similar issue,

Just go through the basics. Timing, cam chain tension, set your valves, sync your carbs, and throw some new plugs in.

See what that does.

 

[650hcs]

carbs werent synched correctly, I wasnt getting enough fuel to the cylinder. Doh