xs2 runs but popping on one cylinder

[nairb]

I have finally re-commissioned the xs2 and had the engine running. Like a lot restorations of old bikes the real faults that stopped it all those years ago surface.
The engine starts well off the kick start and does run evenly on the choke for a short while.
I should point out that the engine has not been rebuilt. And does sound quiet with its new oil and cleaned filters(around 14,000 miles)

The engine does rev freely but does make a lot of "popping" noise from the left exhaust on idle. And the left exhaust seems to run cooler that the right And the exhaust gas on the left does seem much cooler than the right. There does seem to be a miss fire on the left cylinder. With the choke on the popping noise seems to stop.

I fitted new spark plugs/caps during the build. But the left spark plug already has more oil on it that the right. I bet the valve guides may need looking at sooner than later.
But in the short term I just want to get it working and do a couple of 100 miles to see how its shaping up.

It the popping from the left exhaust due to air leaks on the carb side?. Or coil/condenser related.
I have mostly built 2 stroke triples so this big chunky four stroke is a newish area.

Thanks
Nairb

 

[5twins]

It could be air leaks or coil/condenser/points related. A bad condenser could do it. Try swapping the condenser leads between points sets and see if the problem follows.

 

[nairb]

Try swapping the condenser leads between points sets and see if the problem follows.

Good thought. 2 strokes are much simpler. And I have 3 which I can swap the bits over to find the fault. I seem to have only 1 xs2 and it has valves and timing chains

Its difficult to get coils checked nowadays.