Back fire

[el torro]

Happens at idle speed but not on acceleration/ return to idle , on Weber dcoe big valve twin cam,any hints welcome or recommended experts in Scotland

[benymazz]

Any advice I can offer is purely speculative and based on my very limited experience, but is it backfiring through the intake, or is it an "after-fire" (in the exhaust)?

[Donels]

My guess would be an air leak, probably from the rubber seals/misab plates between carbs and manifold.

Dave

[el torro]

Thanks for reply yes I will tighten up carbs to inlet manifold I have fitted the Swedish plates so I think they should take more pressure