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MG Midget and Sprite Technical - carb problem

Hi guys, had to take the airbox off my 72 so i could tighten the exaughst clamp! anway thought i would increase my tick-over as it was at only 500rmp, when i looked at the open carbs i noticed that the front piston was dropping faster than the back piston? topped up with oil and checked what the hand book said, no change! also when i used my tube on to listen to the air flow the front carb was kind of making a (hanibal lector noise) hiss-hiss-hiss and rear carb a steady hiss?

silence of the lambs and snake noises on the forum! who would have guessed!

cheers.
s j knox

LOL - always hard to diagnose a noise on here!!!!

However, with reference to the different speeds - have they both got matching springs?
rachmacb

not sure about springs! dont want to take anything major off until it passes the manx test on thursday! the pistons look very dirty and im not sure if the oil in the dash top is leaking! does that mean new seals?

and there'll be no more noises! well on this forum anyway!
s j knox

Are the dampers the same? check the number on top, there is difference in the free play of the damper.
Alex G Matla

OK - if it is going and is "safe" - then get it through it's test tomorrow - then worry about it :)

You probably just need to tidy them up and clean them all out - the springs are the ones under the dashpots, so are pretty easy and quick to replace anyway, but, it does sound like you're going to need to do a clean up job anyway!!!!!

You could always put up major noises on youtube for ease of explaining ... ;)
rachmacb

Topping up the dashpots is always a worry.

Occassionally I have seen poor running as a result of differing rates on the pistons falling in the carbs. When this has been due to someone topping up one of the dashpots. Both dashpot MUST have the same grade oil in them to allow them to work in sync. So for you please remove the dashpots and empty out the residual oil and replace both sides with the same oil. I personally use motor/engine oil and never have problems.
Bob Turbo Midget England

here is a video from John Twist showing how to confirm the pistons are matched:

http://universitymotorsltd.com/videos-display.php?id=41



Norm
Norm Kerr

Steve, didn't those Jooohn Twist videos help

as regards rev counter showing tickover at 500 rpm - the rev counter can be 1-200 rpm out over the whole range so set tickover at what sounds and looks like on the rev counter just a little too fast

you have to have the both carbs set up correctly to get the tickover right

and before you can really get the carbs set up you need to set the timing

before setting the timing the tappets should be set

hey, sound like elements in a service :)

I know your target is to pass the test but if you do a full 36,000 mile service the car will go much better giving you more of the full potential of fun you can get for your car

so many classic sports cars are run well below the car's actual best robbing the owners heard of, seen dealt with 3 just this week!

no wonder other people have such low expectations of classics if this is how well those owners think the cars go

skake head, roll eyes
N Atkins

Nigel, you forgot; Tsk tsk...
Alex G Matla

Hi guys! before i got the car it was fully serviced, timing done and the like at classic car workshops in notts. its been sweet as a nut purring away, thats why i cant understand whats happened.I followed the twist video and i think i made i worse, cant get rid of the hiss-hiss-hiss sound; surely it should be a constant hiss like the back one which makes me think its leaking or air is getting in somewhere. Drove it today and it seemed ok apart from a bit of lag and revs took a bit longer to drop.
s j knox

yet again Norm posted whilst I was typing

Alex, if I could even remember a bit I'd have a lot more money left, though I think I might have mentioned the Handbook to Steve before

Steve too late at night to think now others will follow with advice
N Atkins

This thread was discussed between 13/07/2011 and 14/07/2011

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