Now, to tune the weber 40 IDF Options

[purple]

I know it's been rehashed over and over again....

I have some questions on how to do it after futzing around in the garage trying to make SOMETHING happen.

I followed the carb clinic instructions to the T and I think something is adjusted wrong... Maybe you guys can help.

I have the idle speed screws to 1/2 turn past first contact with the arms

linkage disconnected

air bypass screws all the way shut.

all mixture screws out 1.5 turns

it'll start and run (slowly) and it'll get to what i think is around 450 rpm or something. really slow..

the only way I can get it to idle at 450 or so is by having the mixture screws in pretty far. two cylinders dont even react past a certain point! i can have them all the way in (lightly) and the engine doesnt change its note at all!

Please ask me questions so I can give the right info. I've never done this before but i'd like to believe these arent fiddly carbs.

When they say the engine should 'speed up' is it a really noticeable change? because mine's so subtle as to be not affected.

please help guys!

these are brand new carbs from jake's store. I have the box that says what the jetting is. i'll post that soon.

what are 'jets' and what do they do?

[SGB]

I start with the screw 1.5 turns out from closed. If I turn the srew counterclockwise in "5 minute" increments, then pause about 3 or 4 seconds, there may be a slight (50 to 100 rpm) drop. It may be just a slight change in tone unless you have turned 15 or 30 minutes worth. Plug fouling makes me crazy when I'm messing with the carbs. 15 minutes at idle speed will choke #3 plug, and then it won't behave right to complete the balancing process. I usually put in new plugs, fool with the carbs 15 or 20 minutes, put in new plugs, mess with it 5 minutes, then drive it for a while to burn of the carbon.
Also, check to make sure the throttle arms are holding the connecting rod to the carb in a perfectly vertical position. As those arms swing down, any difference in the geometry from the angles of the linkage wil become more exaggerated.
Unless the cilynder is not firing due to fouled plug or clogged jet, it will be pretty apparent when the combustion is decreasing.