Weber 44idf's

Fuel pressure is measured in pounds, Richard, and air pressure is measured in bar- 1bar= 14lbs? If you truly have 3bar fuel pressure it's waaayyyyy tooooo high. Should be 3lbs.

Sorry Al, wasn't thinking straight. 3lbs

not "pounds" exactly as we are dealing with pressure, as in pounds per square inch, or psi. A standard atmosphere at sea level is 14.7 psi, and that is a  "bar", as in barometer.  Climb to the top of the Rockies, and maybe you get 12 psi. Or Everest and see about 5 psi.

Richard,did you install the Sync Link yourself?

I'm asking because I've got my new Sync Link kit sitting on my workbench and I was wondering if you had any particular problems with the install.  I did download the install instructions of the Web.

and 3 psi on dual IDF's is good. 

you are on the right track on checking those float valves.  if you are careful, you can take to tops off the carbs without a new gasket.  i've pulled mine apart MANY times.

IDF choke circuit eliminated?  mine have got stuck (opened) twice over the years.

Vacuum leak. 

MangoSmoothie.ca posted:

and 3 psi on dual IDF's is good. 

you are on the right track on checking those float valves.  if you are careful, you can take to tops off the carbs without a new gasket.  i've pulled mine apart MANY times.

 

IDF choke circuit eliminated?  mine have got stuck (opened) twice over the years.

Choke eliminated Mango

edsnova posted:

Vacuum leak. 

I did check and spray some easy start around the vacuum take off's with no effects.

Ron O posted:

Richard,did you install the Sync Link yourself?

I'm asking because I've got my new Sync Link kit sitting on my workbench and I was wondering if you had any particular problems with the install.  I did download the install instructions of the Web.

Ron, installing is straight forward if you have the taller inlet manifolds.

My problem is I have short manifolds which caused a problem with the left carb and the sync link bracket interfering with the Dtm.

What I'm struggling a to get my head round is, if it is the float valve that's worn. Wouldnt the pump jets be weeping??

Anyway just pulled one of top of the carbs to check. Fully open 32.5mm. When measuring the closed position, do I measure from when the float arm makes contact with the plunger or when the float arm Sinks the plunger??

does that make sense?

Found this. It may help others.

https://youtu.be/54uPwTZ3DJw

Is it time to make sure you have all of the "brass thingies" properly installed? Or should we go a few more pages?

"What I'm struggling a to get my head round is, if it is the float valve that's worn. Wouldnt the pump jets be weeping??"

Not necessarily.  The accelerator pump essentially has a diode valve in it to prevent it from draining the bowl.  

My money is on the weak pilot valve(s).  At first I thought about overtemp percolating the fuel in the bowls, but that condition becomes over-aggravated when the bowls are over-filled, so we're back to the float valves.

What'd you find?

Float valves I'm on the fence with. So I've ordered some new ones along with a few more jets etc.

Check around the manifold/head joints and manifold/carburetor joints for leaking as well.

So whilst the carbs tops are in bits, I'm changing a few things to suit the engine more and hopefully make things run smoother.

Things I'm changing are as follows;

Venturi going to 38

Mains gas going to 170

Main A/C going to180

Idle 60

P/jet 50

E/tube staying with F11

Anything that stands out, please shout out. I'm sure you guys have been and done all this before, so could save me some time.

What size venturis are in the carbs now? Engine specs again?

Hi Al

36 Venturi's

Engine is 2270 type 4. Engine has been built for fast road and track use. Lightened and balanced. So will spin upto 7-7500. 

Carbs are presently set up for the old engine 1911 hence another reason to swap a few things.

So valve sizes are 42x37 (or thereabouts)? 38's just might do 7,000; it'll be interesting to see it they do 7500. Keep us posted. 

Stepping in here, 

check float adjustment. With the gasket in place I set them at 9 mm. Before doing that inspect the needle and seat. Be careful on some of the replacement ones. I just had a set the needle part would not move and stayed in the closed position.

your jet stack may work for you but I think that main is a little big and the air jet to small. To run 60 idles you must have some compression and decent cam. If your motor is as big or strong as you mentioned a set of 44 idf or some 48 Ida's would be a better combo.

your idle issue sounds like a vacuum leak or the cable connecting both carb has to much slack.  Your clearance issue could be resolved by using the carb isolators that go between carb and manifold  

as for your fuel leaking is two things, high fuel pressure and or float set to high. The third factor could be non vented fuel tank.

Thanks for the feedback. As we all know what will work for one engine combo may not work for another as a lot of factors have to be taken into account. It's more of a starting point the jet stack.

l was thinking 40 vents with 200 airs. Although after speaking to the carb tech guy he suggested the above. It's his day job not mine which doesn't make his choice right but a starting point???.

Valves are 44/38 pretty close though Al.

Compression is 9.5.1 from memory without dragging the paperwork out and I'm running a Webcam 86B grind.

Until l get it running again I'll check for vacuum leaks more thoroughly. I've had problems with heat before so already  fitted isolators between manifold and carbs during the build. Tank is also vented and working just to tick that box to.

Ideally I would have thought 40mm vents would be the best choice with 44mm intake valves, too, Richard, but people in the know say 38's are the largest you can run on the street in 44IDF's and the carburetors still function function properly. All it means is it may not make quite all the top end power it was designed to, but certainly will be more responsive through the lower rpm's.

And Anthony's advice is usually pretty right on, so I would listen to what  he has to say.  As you said, the jetting is a starting point, so you'll see where it ends up. Al

It's all a learning curve for me. Everyone's  input is valuable info for me and l hope for others too.

l missed the Posty on Friday so will have to wait till Monday for the bits to have a play.

l'll report back my findings.

Just a thought, should l change  the whole lot of vents jets etc in one go?? Or change one at a time and see how it runs??

Start with the recommendations and then change 1 thing at a time, starting with the idle circuit. Don't play with the mains until you have the idle circuit sorted.

Richard, everyone has advice about what to do with Webers.

Some of it can't be printed in a public forum, but a lot of folks think this article is one of the best places to start.

i sold my speedy because of Webers, never again..

Ok, update. 

New float valves fitted and floats measured and set. Fitted new vents 38, idles60, mains170 and a/c 180. Starts and runs better than the old jets. Re synced the carbs without any cables, then re attached the cables. All good.

Problem, on idle l still have 1 pump jet weeping on each carb. Can this be caused by the pump exhaust spill valve at the bottom of the float chamber being partially blocked??? I've noticed air bubbles coming from it or is this normal ?? See link for video.

http://s176.photobucket.com/us...EF54CC56E55.mp4.html

Basically this is a ball valve, I'm thinking some crap is lodged in there causing it to weep which intern makes the pump jet weep??  Is this feasible?

Yup, that's a solid premise.

Once you can get to the port where the ball sits, give it a solid blast with carb cleaner to clean out the port.  Clean and inspect the ball to see if there is any deformity - If possible, measure the ball size and get a couple of new ones the same size, just to be sure (but usually, cleaning the ball seat/port will cure it).

Looks much closer to Nirvana than before, right?

I believe that supplies fuel to the accelerator pump and then to the nozzles.

usually if you have fuel leaking onto butterflies it's the needle and seat are bypassing fuel and not closing. also a high float level can add to it.

I recently had a customers engine fill up with fuel because of a faulty needle and seat.

I've checked the floats and set them at 10mm without the gasket. I'm struggling to accept its these has the first float valves looked ok but to be 100% ordered new. With new float valves fitted the problem is still there, just not as bad. Must be something else I'm missing. 

Gordon the pump valve at the bottom of the float chamber appear to be a sealed valve with a plastic ball valve not metal. I think I'll struggle to clean them to be 100% happy so I've ordered 2 new ones so.

I'll have a closer look tonight and do some more head scratching and report back.

Is it possible that the chambers/holes ( not sure what it's called the tube/valve jets that hold the needle) for the needle are too big for the needle? Recently I bought a top-end rebuild kit and noticed they do have size numbers on those needle tube jets. I had 175's and the rebuilds were 200's.  I used the old needles not the new ones since they looked good and had over flow issues until I changed the needles. I also set my 10 mm adjustment with the gasket on (same as the Youtube video). I have not had a problem with this adjustment. 

Pete

Result.

One problem solved...No leaking pump jets.... I've replaced both pump exhaust valves at the bottom of each carb. The new ones have a steel/stainless ball bearing. My old ones had a plastic ball, so l think better quality. Also whilst in there the screw that holds the pump jet in place is a type of valve also. So l replaced the 2 that were dripping. Could of blasted them with carb cleaner but thought whilst ordering bits might aswell add them to the list. 

Idle is still a problem, start engine and it idles great at 900rpm, blast the throttle and it returns to 900rpm. Leave to idle and warm up, it's fine. Take it out for a run and it now idles at 1500rpm. Look at the the throttle returns screws and the throttle arms is resting against them. I've disconnected all vacuum pipes and plugged them. Sprayed carb cleaner around all gasket joints to no avail. I've tried turning the throttle screws out when it's idleing at 1500rpm to bring it back down to 900rpm but if you leave it 5 minutes ticking over, the idle starts to drop to a point it's hunting and wanting to stall. So I'm puzzled. What am l missing????

one of the most important step in tuning webers is you adjust them when the engine is warm! as the engine expands with heat the linkage moves also.

therefore it should or may run a little rough when cold and be fine once it warms a bit.

Your comments in your last post lead me to believe the linkage is causing your problems or you have a leaking carb. are the accelerator pumps adjusted to far in? float set too high???

It's difficult to diagnose over the internet but hope this helps along with all the other advice you receive from the site.

I've never been able to find a vacuum leak by spraying carb cleaner around.  This is always what everybody suggests, but the place I always have a vacuum leak (if I have one) is at the intake manifold/head gasket, and it's almost impossible to spray all the way around that joint.

I have had the gasket blow out  between the intake ports on heads not have them pretty aggressively ported. I had a side of welded 043's where that joint was about 1/16th of an inch thick. 

Everyone has their own hymnal when it comes to tuning Webers

What's on the first page of mine is what Anthony said about hot and cold.

I used to start it up in the driveway, wait until the oil temp needle was off the peg a bit, and dial everything in. I'd then jump in, and five miles down the road, it sounded like a paint mixer. I'd drive back home, dial it all in again, and set the idle back to 750.

The next time I started it, I had to feed it gas for a minute before it would idle, and those dad-blamed Webers were all messed up again.

It's easy to see why Webers (what most of us have) get such a bad rap in a world of always-perfect computer controlled engines. Remember, our carbs don't even have chokes. There's no way they're going to be happy when they're cold.

Now, like Anthony says, I don't even try to tune them unless they're good and warmed up - which means driving for at least 15 minutes - more in colder weather. You need to let the heat from the heads work its way up through the manifolds to the carb bodies and also let the engine compartment temp get up to where it is in normal driving.

After a while, all the bits and pieces (including the critical linkage) reach thermal equilibrium and only then is there any chance of your engine 'holding' a tune.

It's all a compromise to some extent. My ritual is to come back from a drive, set the mixture screws as lean as they'll go without popping, tweak the idle stops just a scosh to synch the two sides, then set the idle a little on the high side. I use 1000 or even 1100, which most people say is too high, but it always starts and idles no matter how cold it is without having to feed gas. When it's fifty degrees out, it may idle only at 500 or so from cold, and it sounds noticeably 'out of synch'. But after a few minutes at idle, without blipping the gas at all, it gradually works its way up to about 800 and it starts to come into synch. When it does, I drive off.

It still doesn't smooth out all the way for a few more miles, but it's nice to feel it come into tune as you drive rather than the other way around.

Like I said, everyone has their own hymnal and this one works for me. There's another church, on the other side of town - the SyncLinkopalians - whose hymns are even more in tune than mine.

Guys I appreciate your comments.

Engine is always warm before any adjustments are made, these carbs have always been bullet proof in the past.

Problems only started after l fitted the sync-link.

Dripping pump jets, now fixed l can put down to some crap found its way into the carbs whilst installing the linkage etc. I can except that...  Floats have also been checked again.

So the idle problem can only be sync-link related. Throttle arms are always resting on the idle screws regardless whether it's ticking over at 900rpm or 1500rpm. There is plenty if slack in the cable from the pedal to the first pulley for heat expansion also. This is what I'm stumped by.....I think my Sync link must be batch No 666.....

Stan you mentioned porting, which my manifolds have been port matched. There isn't a lot of gasket there l know. If this was the case though would a vacuum leak be present there cold?? I'm thinking if there is a leak, by the time the metal gets upto temp it would seal itself?? Im clutching at straws here.

I'm seriously thinking of pulling the sync-link at this moment. Its going to be a pain in the ass if l do and put the old tried and tested linkage back on just to confirm things.

Any more thoughts before l pull the plug on the Synclink???

I'm sorry if I'm driving you all mad with this problem...

It doesn't sound like it has anything to do with the cable to the pedal. It sounds like the cable to one side to the other is out of sync? Are the wheels properly clocked???

before tossing it (I will take it), go back to the first steps and see if something was overlooked. I have mounted them on type four and type one engines and on the front and back side of the carbs. They are tricky when reading the instructions and applying that information.  It has to be something simple.  

Quick update, after so much head scratching my nails look polished and l have a bold spot. 

Seriously, l think I've found the problem with your guidance.. Manifold to head nuts seemed to be loose on both manifolds. I remember setting the torque gauge at 14lbs when l re-fitted them but whilst double checking everything today l checked them by hand and they seemed loose enough to be able to give them another half a turn with a hand spanner. You were so so close to having a sync-link in the post Anthony.

Took it out for a run and all is good. Back to a stable idle 900rpm. From cold to hot.

Another question for the sync link guys. After looking at various sync link pictures over the net, l found a few pictures showing that some folk only use the one idle stop screw to the right carb and discarding the idle stop screw to the left. After thinking about this it makes sense if a cable runs from one to the other wheel. Making syncing the two carbs more precise?? Although when both sync'd does it not matter??

I've set mine up using both screws but wondered what you guys have done.

I'm just glad something I have to say has some utility.

Good going!

Both screws. Don't overthink it. 

Yeah - what do you do when the cable stretches?   Both screws.