Hi all,
My 72 750 has been running beautifully for 5 years with a new Boyer system, new Amal premiers, etc.
Started during early lockdown for first time in a while to test a reconditioned speedo and tacho I fitted. Popping and banging badly. I thought it might be low battery voltage so charged up. Fitted new exhaust system (very shiny!). No change but seems not as bad. Cleaned out carbs. Strobed the timing. Spot on. Plenty of fuel. Right cylinder running much hotter than left.
Any ideas? I know it could be air leak so checking tomorrow.
Sounds like a good place to…
- Log in to post comments
An intermittent plug spark…
An intermittent plug spark will allow unburnt fuel to go into the exhaust and be ignited by the next spark.When we had heavy steel silencers on our old magneto singles ,a dab on the mag cutout would produce a very effective message to tailgaters . Not a good idea with a flimsy silencer.
- Log in to post comments
I had this...
... on my Commando and was convinced it was fuel. After a long search discovered it was the wires coming from the Boyer pickups which had fractured at those horrible little crimped connectors.
- Log in to post comments
Sounds like a good place to start. I had a very similar problem a few months ago. Turned out to be a leak on the exhaust port. New metal seal and a really good tighten when hot fixed it. It wasn’t quite as straightforward as it sounds, because I checked everything else first - carbs, battery, plugs, coils, Ht leads, wiring to electronic ignition, timing...
Ended up with a blue exhaust pipe since it took so long to find! Good luck
Steve