tuning Webers

[RichC]

having received my nice little airflowmeter ebay purchase thru the post yesterday ( second hand ?18!) i set to balancing the carbs & sure enough both pairs of carbs were out of synch so i gently twisted the spindles back into alignment & what a difference it made!!!!

Now the question i have comes from another coinidental discovery ....
Getting the airflow meter into position on carb 4 is a bit awkward with the pedal box being so close but i did it... however each time i put it on the revs went up a bit!!
Thinking about this i thought it might be something to do with mixture being a little too weak , but idle screw was already fully in . (incidentally, the engine side of this no 4 throttle plate is black with carbon - what does this signify pls?)
After a bit of headscratching i just pushed in the bottom of carb 4 with my hand , mimicking pressure when flowmeter is squeezed in past pedal box and this replicated the rise in revs - it doesn't happen with any other carbs and the faces of the joints are in good nick and o rings are new . I plan to put on a little sealant ( i seem to remember there were remnants of silicone seal around the old O rings which i took to be a bit of a bodge ) can anyone recommend what to use pls? is bog standard silicone seal okay or sould i use something else , blue hylomar perhaps??? - i cant remember if this is petrol resistant or not.
cheers all,
RichC

[types26/36]

i just pushed in the bottom of carb 4 with my hand , mimicking pressure when flowmeter is squeezed in past pedal box and this replicated the rise in revs -
RichC

Because the carbs are flexible mounted and independant from each other by pressing on one carb are'nt you distorting the set up and putting pressure on the carb linkage/cable causing the rise in revs?.........just a thought

[GrUmPyBoDgEr]

having received my nice little airflowmeter ebay purchase thru the post yesterday ( second hand ?18!) i set to balancing the carbs & sure enough both pairs of carbs were out of synch so i gently twisted the spindles back into alignment & what a difference it made!!!!

Now the question i have comes from another coinidental discovery ....
Getting the airflow meter into position on carb 4 is a bit awkward with the pedal box being so close but i did it... however each time i put it on the revs went up a bit!!
Thinking about this i thought it might be something to do with mixture being a little too weak , but idle screw was already fully in . (incidentally, the engine side of this no 4 throttle plate is black with carbon - what does this signify pls?)
After a bit of headscratching i just pushed in the bottom of carb 4 with my hand , mimicking pressure when flowmeter is squeezed in past pedal box and this replicated the rise in revs - it doesn't happen with any other carbs and the faces of the joints are in good nick and o rings are new . I plan to put on a little sealant ( i seem to remember there were remnants of silicone seal around the old O rings which i took to be a bit of a bodge ) can anyone recommend what to use pls? is bog standard silicone seal okay or sould i use something else , blue hylomar perhaps??? - i cant remember if this is petrol resistant or not.
cheers all,
RichC

Dreibond 1209 or 3 Bond 1209 is a colourless modern sealant which is used where necessary on todays BMW engines so it should do the job for you.
It remains flexible!
I'm not sure about Hylomar, probably OK but it's formulation has changed since the days when it was "the one to use".
It, like all modern sealants, needs a completely grease free surface to adhere to; the previously used solvents being suitably modified or banned due to "health & safety"

Good luck
John

[RichC]

thanks brian for that thought !
I'll double check that one ...