Tuning twin carb enginge

[gagvanman]

A year ago the 1600 SP in my van dropped a valve and destroyed the engine just after I fitted twin ICT's. I replaced it with a 1776 from Steve Strong (engine is fantastic).
However, not having much experience with these engines I didn't want the same thing to happen to the new engine so I took my van to a reputable company in Leicestershire to make sure it was tuned correctly and running ok, this obviously cost a fair bit.

To cut a long story short, I just purchased a motorcycle twin carb synchronising kit and checked my carb set up. Needless to say the balance was way out, and now after setting them up myself the engine is running the best it ever has.

To be fair to the company I went to, it was a while ago and I suppose things can drift out of sync, but at the time I did not notice any difference in performance after taking it to them.

Just an observation...

 

[Trikky2]

Its not unusual. These days finding somebody who is good with carburettors is getting hard and twin carbs even more so.

The technology has moved on and many experts are reaching retirement, so you now need a specialist rather than being able to use any good local garage.

Then there's the old adage "if you want something done properly ....." :lol:

 

[trinketpimp]

Gag,
Been thinking of gauges myself, which ones did you go for, or anyone else have some they would recomend ?

 

[TeamBrian]

I bought myself an airflow meter (similar to VW Heritage pt no.ac000124) which has earned it's keep many times over. Can't really comment on the vacuum types though as I've never used one.

 

[K@rlos]

Its not unusual. These days finding somebody who is good with carburettors is getting hard and twin carbs even more so.

The technology has moved on and many experts are reaching retirement, so you now need a specialist rather than being able to use any good local garage.

Then there's the old adage "if you want something done properly ....." :lol:

I agree completely, I'm a 25 yr old HGV mechanic but I do cars at work too and I'm the only 1 there who knows how to change points, set timing and tune a carb. I admit I don't fully know twin carbs yet but my mate who built my 2110 is gonna school me in twin carbs so I don't have to pester him every time it needs a tune up :lol:

 

[jonboylaw]

Twin Carbs are not difficult, nothing mysterious about them, just twice the amount. Be methodical, first thing to check and sort is the linkage, make sure this is working as intended and give the same throttle movement at each carb and gets to WOT at the same time. Once that is done then it is just balancing port to port, carb to carb. Seen a guy do an old Lambo with quad weber 48s on, that took a little while to sort.


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[gagvanman]

I think I have a good way to tune my ict's now. Disconnect the throttle linkage from one carb. Set the mixture screws to 3 turns, use a flow meter to get both carbs to the same flow (might invest in another flow meter, so no need to keep swapping over carbs). Then use the motorbike synchronisers to get the throttle levels the same for each carb after reconnecting the linkage. Before I did this I found that although the mixture was fairly well balanced, one side of the engine was revving higher than the other.

 

[Geeze]

Sounds like you've got the hang of it, disconnecting the linkage is the bit most folk miss and then chase their tails forever trying to get everything adjusted together all at once.
If you've got twin carbs a unisyn or similar is a worthwhile investment as they do drift out of sync but you can get surprisingly close with an short length of old hose and a good ear.