i'm stumped. at idle, i get a pulsing of fuel out of both of the accelerator pump jets on the pass side carb. they do not not leak with the engine off, with the key in the first position and the fuel pump engaged. driver's side does not exibit this. it occurs whether the linkage is hooked up or not, and the engine is idling. valves adjusted. i've been thru the setup proceedure repeatedly. side to side carb flow is balanced.

give me some ideas. the actuating arm is not bound on the cam and moves freely. so...incorrect float adj? stuck diaphram or one of the check balls missing or stuck? looking at the cutaway diagram on p58 of the cb book shows a good view of the circuit. there can only be so many issues.

i contacted the outfit that rebuild my carbs. their diagnosis was tight intake valves and the back pressure upon compression was forcing the fuel out. that didn't make any sense to me.

k

I think you have a hole in the diaphragm. Then air pressure pulls fuel out of the jet.

Just curious?? Can you swap the carbs from side to side?? Then see what happens.
CCL

Here is another possibility....

There is a check ball built into a screw UNDER your accelerator pump squirter.

OR you have the early version which is a free check ball under a little brass rod.

Either way. Yours is probably corroded or dirty or simply hosed.

NOTE: Mark Harney has some REALLY good articles on rebuilding the weber carb.. Ya might want to peruse them and see if you can glean any new data for your carbs.

Mharney Weber Pages

Cheers,
Clayton

mr harney's site is the real deal. thanks clayton. i'll be calling at 0530 to 0600 pdst on monday and see whatszup.

k

i'll use this thread as a continuation of the discussion. i have options. i have a set of 44s (italian) available for use. in the first set of pictures i'll share the difs. the 44 is shown on the left.

1. note the dif in the adj pump jet rod vs the solid non-adj style on the 40.

2. note the 'helper' spring on the end of the throttle shaft and the lack of on the 40.

3. the idle adj screw contact arm is 'clocked' differently on the 44. on the 40, the linkage connection points in the correct orientation. it makes for the proper operational direction and maintains fairly verticle linkage drop rods. hopefully i can swap out the one on the 40 to the 44. my linkage 'swings' down as opposed to 'pulling' up to open the throttle plates. i've wondered why folks run the linkage on the rear side of the carbs. i think this is the reason.

4. the main jet stacks are quite tall on the 44 as opposed to the 40.

the 40s have 28mm venturis and the 44s have 36mm. reading harney's recommendation of going 4-6mm smaller than your intake valve size, puts me right in the ballpark with the 42mm valves on the stock 2.0 heads. i 'think' arron has gone to smaller vents on his hopped up 2.0, 32s?

i feel my best path at this point is to walk away from the 40s and put my time and money into the 44s which ARE the ones i intend to use, when i venture down the new engine path, due to size overall and the difs noted which i consider upgrades/improvements.

k

i have 34 vents on my 44's...
i may step down to a 32.

i was just out looking at the 44s in the freezing cold garage. p.o. must have thought he needed #100 tq on the airbleed screws to tighten them up like lug bolts. damn, screwdriver slots on a few are all galled up tight, jam nuts and the screws themselves tight as a mofo. a light touch is all it takes.

with the 34s, what percieved issues do you think have? boggy responce off idle at throttle tip in? where do we go shopping for the best deals? i'd prefer not to have to ship stuff from italy.

damn...why? gave them some areokroil to try to loosen them up.