Adding Dual 34mm Weber ICT Carburetors
A good way to add some power and efficiency to your motor is by adding the right set of dual carbs. I say "the right set" because just buying the biggest set you can find and slapping those babies on your stock 1600cc engine would be a bad move. Instead, I feel carburetion is best when taken with a bit of moderation. I was planning to run either 40mm Kadrons or 34mm ICTs with this motor because of two major reasons:
1. Either's reputation for reliability and ease of tuning. Dual single-barrel carbs are typically less efficient than the dual two-barrel carbs (DRLA & IDF types) found on race cars, but they are often times easier to tune. There is NOTHING electrical on these carbs to break down and possibly leave you stranded unlike the later stock Solex carbs.
2. Either's reputation for good, low to mid range performance while maintaining a high degree of fuel efficiency. Have you noticed the price of gas lately?? 'Nuff said. . . ;-)
One thing I've found REALLY helpful when setting up dual carbs for the first time is to pre-set the butterflies to a known clearance. This sort of pre-syncs the carbs so they are easier to get started right out of the box. When the throttle is in the closed position and resting firmly against the throttle-stop, I use a feeler gauge (.004" in this case) between the butterfly and the ventri. I adjust the throttle's idle speed set screw to adjust this so that they are both carbs are equal.
Next I pre-set the idle mixture screws. CAREFULLY & GENTLY bottom out the idle mixture screw on each carb and then back them out 3 full turns. Now the carbs are pre-synced.
Now you're about ready to mount them on your engine. In every engine gasket set, there is always 2 tin (metal) manifold gaskets. I don't really trust these to seal properly for years to come. I much prefer the fiber gaskets which, I've found, can be trusted to seal and re-seal time & time again. Plus, if you buy the thick gaskets, you get a degree of vibration dampening too. You should match-port the gaskets with a razor blade so that they don't inhibit the mixture from flowing in your engine.
I will usually mount the carb and the manifold on the engine as a unit since it's easier that way. I'll mount one side, then I'll position the cross bar in it's receptacle. Then I'll line up the cross bar on the other carb and then work it down on the head studs. Now the washers and mount bolts can be added and tightened.
The linkage can be loosely installed at this point, but there's no need to tighten it really since once you fire up the engine, it will all need to be adjusted during the actual sync process.
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Revised: August 29, 2003 .