Is there any advantage in using a dual bellcrank linkage on a Weber set-up -- the sort where each carb is actuated by its own tie rod -- vs the type where the front carbs drive the rear ones via a tang?
Thanks,
John
Thanks,
John
Weber linkage
- Thread starter toy264
- Start date
David Morton
Lifetime Supporter
None at all. Provided they are all work in unison, keep it simple.
Dimi Terleckyj
Lifetime Supporter
The main problem to avoid is the slack or looseness in the joints of the linkages as the end carb gets the aggregate combination of all the looseness and doesn't operate in sync with the first one.
Dimi
Dimi
John
I find a separate link to each carb or throttle body is better.
I find it easier to tune.
Don’t use cheap stuff.
Baby rose joints (3-4mm) are better than the ball and socket style link.
Jim
I find a separate link to each carb or throttle body is better.
I find it easier to tune.
Don’t use cheap stuff.
Baby rose joints (3-4mm) are better than the ball and socket style link.
Jim
Unfortunately, there is no "universal solution" and we have to adapt it according to our specific carbs arrangement. It is possible to drive Weber trottles by different ways but I like to use the dual bellcrank system that has a good effort distribution in the dual crank axle. This design as been selected by Englese that is a renowned Weber specialist. In the small video here attached (sorry for the loading time 
)
Commande des carbus - eSnips, share anything
you can see my specific adaptation with a lateral connecting rod (no space and no access in the center valley). This design with ball bearing connecting rods allow to have a "Master" carb to adjust your trottle. The three other carbs are "Slave". You have to check first that all carbs are fully closed when the master carb trottle screw is untighted. As there is no rod interplay, when you screw or unscrew the master trottle, slave carbs are following perfectly the master adjustment. I use this system from 1 year ago without noticeable upsetting. This rod system will also allow to adjust the trottle progression according to the initial crank angle adjustment. It is possible to obtain only 25% of trottle openning when the trottle pedale travel is at 50% and of course 100% when the trottle pedal is at the bottom. This adaptation increase the trottle sensibility to go out from a small corner.
This is only one of several solutions but mechanic is like cookery, everyone has is own formula
)Commande des carbus - eSnips, share anything
you can see my specific adaptation with a lateral connecting rod (no space and no access in the center valley). This design with ball bearing connecting rods allow to have a "Master" carb to adjust your trottle. The three other carbs are "Slave". You have to check first that all carbs are fully closed when the master carb trottle screw is untighted. As there is no rod interplay, when you screw or unscrew the master trottle, slave carbs are following perfectly the master adjustment. I use this system from 1 year ago without noticeable upsetting. This rod system will also allow to adjust the trottle progression according to the initial crank angle adjustment. It is possible to obtain only 25% of trottle openning when the trottle pedale travel is at 50% and of course 100% when the trottle pedal is at the bottom. This adaptation increase the trottle sensibility to go out from a small corner.
This is only one of several solutions but mechanic is like cookery, everyone has is own formula
I most weber intakes that I have sen the carbs are to close together for that type of linkage. The throttle shafts practically touch. That looks like a Yates head with a custom intake. I have always used the single center crank with out fail. I really beleive with weber linkage, less is more!
