exhaust silencer exploded

[ROBRIOS]

hi guys

after a faultless 2 day trip down to cornwall from york and a day out to the beach today i have just started the van (1600 ct) after a pub tea. there was a massive back fire (air bomb fire work loud), the engine was still running but now very noisy.

back at base i have had a look and the silencer is split in 2.

i have got a new silencer and fitting kit on the way for wednesday and have nearly got the silencer off. should be no worries fitting the new kit.

what worries me is why it has had such a massive back fire big enough to split a silencer ?

we had pulled up a long hill then down hill into the car park, i always let the van tick over for half a min before switching off.

what do you guys think ?

Rob

[kevtherev]

weak mixture on the overrun collected in the exhaust and detonated with the wasted spark/hot exhaust
suspect an air leak on the the inlet side.

[ROBRIOS]

cheers will check over inlet and servo pipes

Rob

[Oldiebut goodie]

I wouldn't have thought that the exhaust were hot enough for that after having been left, and there wouldn't be over run upon starting.
Excess unburnt fuel has got in there somehow though.

[kevtherev]

Ah missed that bit.. sorry
flooded carb, maybe pushed some fuel into the silencer ?

[sarran1955]

Hello,

All sounds rather dramatic!!

Did the exhaust popple and bang on over run, esp in 2nd before all this

A bit complex the exhaust tubes on a CT. but essentially make sure there are no holes or leaks.

Do you have Hall ignition, (aluminium heat sink in lhs of engine bay.)

Happy CT ing

Cordialement,

[ROBRIOS]

removed damaged silencer. the explosion has split it along the seam.

have beaten it back to shape, plated it up and refitted it to make van useable and so far no more explosions

have checked the inlet tract and vac pipes etc all seams ok

new silencer here today hopefully so will stick that on and see how it goes

before the explosion we had run up one of those hills that is too much for 4th but too slight for 3rd and the time spent in 4th probably chucked un burnt fuel through to the silencer, van was only running for 2 mins from cold before we hit the hill so choke may still have been open.

any how cheers for your ideas

rob

[82JEW75]

before the explosion we had run up one of those hills that is too much for 4th but too slight for 3rd

Drop to 3rd and let it pull up to the rev limit (3 red/orange dots on speedo), always, don't labour the engine in 4th as this will send your cylinder head temperatures through the roof, aside from any other issues.