Technical Backfire & Gunshot when switching off engine

[the hobbler]

The 'Michael Speeder' exhausts are still available from Lucasz Reszczynski at "LP Garage" in Sudbury---they are now about £140 each. The mounting bracket looks a little 'light'---I would suggest that a 126 set of brackets would be a better way to support it.

 

[lazylobster]

Some examples of twin pipe styles. I'm not sure what engine you have fitted, but the styles below are available for both 499 / 594 - 652 engine sizes. These are fruity but not to the degree of waking the dead.

R


https://www.ebay.co.uk/itm/30332495...awXB6x3pOVBi82sqimCN7GcIH9sCARe8aAgBXEALw_wcB

https://www.ebay.co.uk/itm/32204841...ZF8EXUju7wxPL3H9kWfLG16aQK9BtqvQaAhYHEALw_wcB

https://www.ebay.co.uk/itm/14393931...Fs7eWOjnaGIRpPiKMyah1Awhhof_E4lMaAt5-EALw_wcB

 

[ClassicFiat500]

Hi Berkeleyman, thank you so much for your reply & digging out the old paperwork. It’s amazing how much things have gone up in 6 years (I blame it on Brexit) however I have noticed the Michael Speeder box has 2 input pipes to it where as the one I have feeds down from the manifolds into one, I think this could be one of the reasons I am getting the fuel burn off explosion. I say one reason the other has to be why it gets into the box in the 1st place, i.e over fuelling. There are so many configurations of silencers from single input to double plus double input from each end etc. I suppose the longer it takes for the gasses ( & waste fuel) to get int the box the less likely is an explosion.
I know its a while since you changed your box on Poppy but can you remember if the old box had a single input (as mine is) from the manifolds or were they split? I spoke to Barton Garage yesterday & their mechanic said they have seen this problem in the past and as they said Valve setting are very important but having the correct silencer COULD contribute to a remedy.
Barry

 

[berkeleyman]

Hi Barry, My old exhaust was also a sports exhaust and also had two separate input pipes, one each end. I have had no more issues with the engine in any way and although I do very little mileage each year I have not had any reason to make any significant adjustment, in fact I don't think I have had to reset the valve clearances in all that time. my annual service tends to be oil changes, steering king pin greasing and brake and wheel bearing checks. Plus of course liberal application of Waxoil to stop it dissolving! I hope my input has helped you with your problem, Regards Eric