Britbike forum Forums Thread Like Summary - What did I do wrong?

Bike is a 78 T-140E with twin Amal Mk2s. So over the summer the bike was running fine, but my rocker box gaskets started leaking quite a bit, so I replaced them, set the valve clearances and re-assembled everything. Now the bike isn't running right. It pulls strong from a stop but as soon as you get up to speed at higher RPMs it misfires. I' tried re-synching the carbs which i've done before after owning the bike 10 years now, still getting the same issue. Plugs were new N4C and after I took my test ride they look lean. In neutral with the bike running if I rev it up it will miss and pop out the left side muffler. I re-checked my intake valve clearances and they were dead on. I haven't had a chance to check the exhaust valve clearances yet. Any ideas? Thanks in advance!

Looked over my connections at the ignition coils and what do you know? Connector to the left ignition coil wasn't connected. I assume it got pulled loose when I removed the battery trickle charger leads from the battery or it rattled loose at some point. Thanks for the replies from you all, I appreciate it!

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Do I understand correctly, that it was running fine before the service?

What all did you disturb when you were working on the engine? It sounds like you've double checked some of your work but maybe not all of it. The first thing I think I'd do at this point was put the old spark plugs back in that you removed during the service and see if it changes anything.

Sounds like an issue I had that turned out to be loose wire connectors on the ignition coils. Others on the forum have had that happen also. Check all your ignition wire connections.
It ran fine until I got up to cruising speed (40-50) at which point engine vibration would cause the connector to "dance".

My thoughts exactly. Something moved. As long as you are checking connections, clean them up and squirt a little dielectric grease into them.

They have a saying over on the Honda forum ... ninety percent of carburetor issues are electrical