Hi guys
Just fit my new "quiet" system to my 1600
Problem is im having backfiring every now and then and when i let off the accelerator in 3rd and fourth the car...splutters (id call it). Sounds like a weak backfire.
So far iv had mixed opinions as to whether this is bad or not.
Someone said increase carby jet size (as opposed to air fuel ratio) to eliminate this, if so what is a good size upgrade for a stock carby.
In another topic i said i was able to get a hold of twin dellorto 45mm's, would it be possible to use a single or are they still too big?
Thanks alot guys, im getting alot of help through the forum and the more people respond in the same way, the more sure a learner can be of whats right

Are you 100% sure you dont have a leak??

The slip joint / clamp on the headers where they joint at 1 and 3 cylinders is usually rubbish

I reckon you are leaking there

As for carbs - 45's could work if you change the venturis to 32's
Singles are usually a real bitchto jet properlly

The headers run into the standar heater channels and as they didnt meet up i had them welded and "exhaust concreted"
It seems as though there is no leakage at all

To check for exhaust leaks, when engine is cold and idling, block the exhaust outlet and you should hear any leaks until the engine stalls. Otherwise you must have a carby wear/tuning issue or an inlet manifold leak creating a lean condition.

Concreted exhaust sounds interesting

I might try that, one person said to me that the car might just need to be tuned for that exhaust (air/fuel etc)

had similar problems one, check your exhaust gasgets, failing that it might be unrelated to the exhaust, check for manifold leaks, points, timing, if your timing is too retarded it will backfire, points with too small of a gap it will backfire, or you might be running lean on the carby.

tune your engine.

Matty is right, block the tailpipe and listen for a chuff sound. Any backfiring from the exhaust is from a leak!, had many cases even from the smallest pinhole. Just make sure its not backfiring through the carby and your getting confused, it may cause u to bark up the wrong tree!!!!

135 main jet for the stock carb