weber carb tuning

[steveo3002]

anyone got experience tuning a weber 

 

i have twin choke weber was on a polo 1300 , car now is 1400 and has a slight stumble if you boot it under load when the 2nd choke kicks in

 

any pointers or beginers web sites i could look at

 

i notice the replacement jets come in steps of 5 , how much of a step is it ?      

[barefoot]

No idea, but my Scirocco 1.6 is running on a carb jetted for an 1800 and it overfuels & bogs at high revs.

I asked what size jets I'd need on sciroccoregisterforum.something & was given a comprehensive list.

It's booked in later this month for a transformation.

There must be a Polo forum as well?

[steveo3002]

i have got some advice from fellow owners , but polo forum is mostly kids that dont know what a carb is  

[derskine]

.05mm I think. For example if it's 180 and 185 = 1.8 and 1.85mm.

My advice would be to buy a few incremental drills and step up the jet size until you get it running right, this may work out cheaper than buying loads of jets.

I've done this before, just put the drill bin in a vice and spin the jet on it (they're brass so soft).

 

When you get it right you could buy the correct size jet, but in my experience drilled jets are okay.

[Bren]

A rolling road session is money well spent.

[Uncle Jimmy]

Webers, that is single Weber carbs are pretty easy to tune up, there's an idle jet with a screw to control fuel feed, a throttle position stop, the accelerator pump leading to a second jet and some kind of choke, manual or coolant operated.

Rather than start mucking about with jets or spending money on anything, check your carb and fuel are clean! Check that your timing is spot on and your getting a good spark. Rule out everything before getting into the technical stuff. Webers are great carbs, hence their popularity, the positives are their ease of tuning and responsiveness, plus considerable powah gains (often with exhaust/ manifold and other mods) The negatives? Often increased thirst, propensity to go out of tune dependant on environmental changes and tendency to air leaks.

[steveo3002]

timing etc is fine.....ive increased the capacity of the engine by 120cc ish so its expected that some adjsutments might be in order