BSA A65 Hornet uneven running - developments at Performance Classics.

In this video, a pilot jet and needle jet have already been replaced with some others of the same sizes and the carburettors in their entirety, as well as the plug leads and caps have swapped cylinders, along with new spark plugs in efforts to fix an uneven tickover and a stammer coming off tick over on the right side.
Very little changed, even with the 'suspect' carb dismantled and checked, but those fibre washers between the jet holders and carb bodies were too thick and needed to be changed ...

[@howardhodgson136]

Doing a great job Paul,testing at times as these old girls can be....

[@paulhenshaw4514]

Thanks Howard - nearly there!

[@peterpinello9286]

Hey what's up Paul. Frustrating stuff. When you swapped the carbs did you swap the spacers? Maybe an air leak between spacer and head? Also, when you swapped carbs did you keep the slides with the same body? Could be one slide is a bit worn and when you swapped carbs and plug wires it stayed with that side because the cables and slides were left in place.

[@paulhenshaw4514]

Hi Peter, the slides swapped sides with their respective carbs and they are brand new brass ones, in reconditioned carbs. In the end, and as can be seen in my last video featuring this machine, I finally sorted it by advancing the timing a couple of degrees - even though it had been set spot on by strobe previously and as a result was never considered a suspect!

[@fergushooper9755]

Well done, sounds great, but l can hear what your talking about. Won't be long before you have it sorted, be interesting to know what's causing that.

[@paulhenshaw4514]

Thanks, I hope to get to the bottom of it soon!

[@niallsommerville9941]

Frustrating, suggestive of a fluctuating bowl level but swapping the carbs has ruled that out. If anybody can find it it's you.

[@paulhenshaw4514]

Nudging the correctly set ignition timing a couple of degrees more advanced seemed to do the trick. Weird.

[@farric1]

Did you check valve clearances too?

[@paulhenshaw4514]

Yes, as mentioned in the clip - 8 thou inlet, 10 thou exhaust and compression good and equal on both cylinders, timing spot on, carbs set up identical [even swapping them made no difference]. Bit of a puzzle.

[@verdelldelap2195]

Switch the coils.

[@paulhenshaw4514]

I got it running fine in the end. If you, or anyone else may be interested, watch these videos and see the whole story for yourselves.
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