I can relate. I've gone through most of my E3 and everything is either newly painted, new parts or cleaned up. I opened the hood on my coupe the other day and just shook my head. Let's just say I don't open the hood when I go to Cars and Coffee.
Weber carb linkage over-rotates and locks full throttle
- Thread starter dang
- Start date
I can relate. I've gone through most of my E3 and everything is either newly painted, new parts or cleaned up. I opened the hood on my coupe the other day and just shook my head. Let's just say I don't open the hood when I go to Cars and Coffee.
This is what I was referring to in my post above. In this picture you can see the stop. It is the angled piece toward the right of the picture. When bolted in place, there is no way this could fail. The question is whether it stops the Z shaped portion of the bell crank in the right position to address this particular problem, and since I have a different linkage and different carbs, I can't tell.
I'm thankful you're doing the thinking that the engineers of the kit should have done. Have you tested the linkage via the pedal yet? I'm curious whether the effort / feel is different with shorter or longer levers involved.
I went first, you have nothing to worry about!
I found a photo of a '73 CS parts motor that had the linkage stop. Looks like it stops it in the return position and wouldn't help in the WOT position. At least not without some mods. How is it suppose to work with the adjustment of the idle stop screw?
My zeniths arenin a box and my DGAS38’s don’t seem to have this problem.
But zero knowledge has never stopped me from opening my mouth, so here goes:
Is it possible there is a different arm on the front and rear carba and youv’e got a rear carb arm on the front?
Otherwise I like the idea of getting slightly longer adjustable push rods for the two carbs.
John
But zero knowledge has never stopped me from opening my mouth, so here goes:
Is it possible there is a different arm on the front and rear carba and youv’e got a rear carb arm on the front?
Otherwise I like the idea of getting slightly longer adjustable push rods for the two carbs.
John
The carb links are the same length. One is set in more of a non-adjustable way and the second has an adjustment to fine tune it to match the first one.
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A followup on the linkage. I looked around quite a bit for adjustable linkage for the carbs and couldn't find anything in the right size. All were too long, so I started searching for just the ball end connectors and bought some nylon ones that looked okay. I got them in over the weekend and they're much better quality than I expected and after cutting up a couple bolts for the links I got them on the carbs. They look like they'll work fine. We'll see. Pre-made link assemblies were $22-25/ea plus shipping, if I could find them. These links cost me $9 for both including shipping. I'm a proud cheap bastard!
Again...thanks Forum for providing valuable experiences and information!
I am reassembling my bavaria and converting over to 32/36s and have found this same problem. In addition to possible WOT, the gas pedal has a 2 stage feel; normal feeling for the first bit and then a heavier feel as the linkage flips over and is over centre. Adjusting the linkage to be longer keeps it from going WOT but the 2 stage feel is still their.
I like the solution of the linkage pulling the carb linkage (with carb linkages that are clocked at about a 4 o'clock position) compared to the linkage pushing up on the carb linkage (carb linkage clocked at about 2 o'clock position). I may have some spare carbs with the linkage or maybe its worth fab'n a few up either out of weber linkages or some steel plate.
I think a solution may also be orienting the adjustable linkage so it is more vertical vs. sloping (as seen below). This solution is theoretical and requires moving the ball pivot closer to the linkage's rod by drilling a hole and using a bolt on pivot ball. I included a picture below with a theoretical blue circle of the new position of the pivot ball.
I am going to look into both solutions and will report back...
Regards,
Bill
You'll have to mock something up to test the amount of travel. The arm on the carb has to go vertical to be WOT so putting the ball joint where your blue mark is doesn't seem like it would have enough travel. Because the two arcs travel away from each other it makes it more difficult for a smooth transition.
Back in my mechanical design days I'd just make some 3D models and test it a bunch of different ways.
Back in my mechanical design days I'd just make some 3D models and test it a bunch of different ways.
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HI
Asking Google, I have found the throttle linkage for Weber ICH or ICT carbs. This has the correct orientation to put it under the throttle rod levers. I ordered a few and will see when they arrive. In the mean time I will play with mockups and fab up a few options.
Regards,
Bill
classiccarbs.co.uk
Asking Google, I have found the throttle linkage for Weber ICH or ICT carbs. This has the correct orientation to put it under the throttle rod levers. I ordered a few and will see when they arrive. In the mean time I will play with mockups and fab up a few options.
Regards,
Bill
WEBER ICH & ICT CARBURETTOR BALL TYPE THROTTLE LEVER - Classic Carbs UK
WEBER Carburettor Single ball-end lever.
classiccarbs.co.uk
Hi,
So far I tried,
1. original throttle rod + longer horizontal throttle arms = this was really prone to wide open throttle and the gas pedal had a 2 stage feel (easy then much harder to push which resulted in WOT),
2. original throttle rod + shorter downward carb throttle arms = this did not work at all; there was no room for linkage arms to pull up on the carb's throttle arms. I was hoping this would work because I think WOT would not happen. I bent in some offset like the longer horizontal arms.
3. Weber throttle rod and adjustable throttle arms + longer horizontal carb throttle arms = this works quite well; the pedal has a consistent feel to it; but if pushed too far WOT happens. WOT happens because of flex/slack in the components not because of setup. I plan to make a 'stopper plate' for this set up. See pics.
The combo I did not try (but may) is,
4. Weber's linkage rod and adjustable arms kit + shorter downward carb throttle arms. The longer Weber adjustable throttle arms may allow the shorter downward carb throttle arms to be pulled up without WOT happening.
So far I tried,
1. original throttle rod + longer horizontal throttle arms = this was really prone to wide open throttle and the gas pedal had a 2 stage feel (easy then much harder to push which resulted in WOT),
2. original throttle rod + shorter downward carb throttle arms = this did not work at all; there was no room for linkage arms to pull up on the carb's throttle arms. I was hoping this would work because I think WOT would not happen. I bent in some offset like the longer horizontal arms.
3. Weber throttle rod and adjustable throttle arms + longer horizontal carb throttle arms = this works quite well; the pedal has a consistent feel to it; but if pushed too far WOT happens. WOT happens because of flex/slack in the components not because of setup. I plan to make a 'stopper plate' for this set up. See pics.
The combo I did not try (but may) is,
4. Weber's linkage rod and adjustable arms kit + shorter downward carb throttle arms. The longer Weber adjustable throttle arms may allow the shorter downward carb throttle arms to be pulled up without WOT happening.
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jmackro
Well-Known Member
By "shorter downward carb throttle arms" are you referring to the arms mentioned in your post #30? The part # 4502720200 from Classic Carbs in the UK?
Have you done any experiments using the original, BMW bellcrank that acts on both carbs? The long arm with three, welded-on levers that gets pulled down by the bellcrank on the side of the block and pushes up on the two carbs? Your pictures all show an aftermarket part in that location.
That is the standard bell crank for an automatic, manuals used an L shaped crank. You can move the balls on these to change leverage.
Hi
I have not received those yet. Though I found the mentioned shorter downward clocked ones in my tickle trunk.
Yes; 1 and 2 above used the original throttle rods (you call this the bell crank). I have not tried to re-position the long rods that come up from the mechanism on the block. I am assuming these do not need modification.
Bill