Explosion/popping sound comming from carb?
Turbo Mini Forums

Hey guys,

my housemate Tom bought a 1275 mini today with a stage 1 kit (he will be joining us on this club in the next couple of days) it ahs a cone filter on it so sounds quite loud, however it makes this exploding type sound and its deffinatly comming from the carb area - it only does it when the cars driving and has been getting worse.

Its a really loud bang - makes me jump everytime

Any ideas would be really good :)

Cheers

Craig

Sounds like timings out.

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


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I've just noticed it has a hs4 carb as well - being a 1275 shouldnt it have a hs6??

umm, forgot to mention the car was running fine earlier - we drove it 150 miles before this started to happen, would that still indicate timing??

sounds advanced i think, if its still on points when they wear out the timing advances, i dont know if its enough to cause this though
[edit] it could also be very very lean at the point where it does it and also check valve clearances could have a valve not shutting when hot

Edited by Brett on 25th Apr, 2012.

Yes i moved to the darkside

Instagram @jdm_brett

Lean mixture is my guess, maybe an air leak.

if its on a dizzy and the clamps not tight they can move just have a check with a timing light

Done now needs redoing lol

Could the car have developt an air leek some where?..

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here guys:

http://s454.photobucket.com/albums/qq263/C...nt=9b5ed4cd.mp4

give it half a turn more fuel and see what differance it makes


Edit-- dashpot oil?

Edited by Brett on 25th Apr, 2012.

Yes i moved to the darkside

Instagram @jdm_brett

check the vac advance hose is connected and not split

Edited by apbellamy on 25th Apr, 2012.

Oil in the dashpot?

one day boost will be mine!

we adjusted the nut on the bottom (its a hs4 carb)

where about is the vac advance hose mate?

little hose from carb to dizzy

Done now needs redoing lol

there is some oil in the dashpot - how would we know if its that?

is the dash pot full?

Done now needs redoing lol

not sure, there was this dip stick thing in it? I didnt even know it needed oil till tonight! How much should it have

Fill it till its about half inch from the top and slowly put the damper back in.

one day boost will be mine!

okay thanks guys,

tomorrow we will be checking/doing:

dashpot oil
vac hose
turn the mixture nut on the bottom (again)
dizzy being on tight

all else fails ill ring up SMMC and see if it needs a tune as its a stage1 kit and might not have proper needle

which way do we need to turn the nut (facing the engine with bonnett up)

can use dashpot oil but engine oil will do, check it with a timing light if you have one. Itl show if dizzys moved

Edited by wng691s clubby on 25th Apr, 2012.

Done now needs redoing lol

I used some general purpose oil I found in the out house as I had nothing else to put in, and it's still in there now. Lol must remember to change it.

one day boost will be mine!

I dont have a timing light =[

iv heard 3in1 oil is quite good

Done now needs redoing lol

after checking the above (didnt top up the dashpot)

played with the nut on the bottom of the carb got it to stop popping when reving on the drive, to it for a quick drive all went well,

then 2-3 miles later it started all over again,

looking at getting it set up and needles changed by SMMC on the rolling road on monday if i cant sort it by then,

adjusting the nut at the bottom doesnt make much difference as i turned it back a few flats, because it began to bog down i presumed it was now over fueling.

also cleaned up the dizzy contacts didnt make much difference realy