Pierburg 2E3 choke

[CJH]

One of my spares has that part broken too - in fact I first thought that was the part the OP was referring to in his original post. Couldn't see how to dismantle it easily though.

[itchyfeet]

... perhaps we should...

that means you CJH

that's to stop the 2nd choke opening when throttle is closed, I guess it would rev hard at idle with that broken.

[CJH]

... perhaps we should...

that means you CJH

Haha - yes, I spotted that. Happy to have a go once we see how the first part turns out.

[Mocki]

hahaha, yes i worded that bit "cheekily" sorry!!

it was a bit of a bugger to change,, i had to take the flap off the splindle and remove the spindle and drill the "rivet" centre out , i then tapped it m3 and put a cabinet m3 screw in to secure it onto the shaft when replacing onto the other carb

the old one was in three bits ( well i had the middle bit , it had no ends!!)

[Chunky-monkey]

Hi Chaps,
I'm new to this forum malarkey, but thought I'd give it a go as much like yourselves I have the same problem with a T25 1.9 wbx carb, in as much as the choke butterfly shaft plastic link has also broken (split in half). Mine looks exactly the same as the one you have reproduced, as you would know I can't find one anywhere!

Are the links you have had made for sale? If so any chance of purchasing one?

[CJH]

They're not available yet, but I'm planning to order a batch in the next couple of days - just need to find time to arrange enough of them into a container and then upload the resulting file. Apparently they take about a week to turn around, so they should be available from next weekend with a bit of luck. I'm not going to charge for the ones from this first batch, as they're untried and untested, so all I need is a PM with an address to send them to. If they turn out OK I'll be happy to post the CAD files for others to have made, or I could have another batch made and sell them at cost.

In the meantime, I have a couple of the ones from the test run, but they don't fit very well - you'd have to enlarge the holes a fraction. That's easy for the round hole, which can be drilled, but the slotted hole is a bit more difficult as the material is quite hard to file.

[Mocki]

i just looked at one of the other carbs i have and the choke bit is ok, but the same throttle flap bit as i pictured yesterday is also broken.... thats two i need now!!!
need to find a better way of changing them , drilling the end off the rivit is ok, but tapping and using a screw may not be the best way forward..... even with thread tight it may still come off

[ian prior]

Thanks everyone for your help. Looks like those replacement parts could be a goer; I'll get our van booked in to the garage as soon as possible, and send you the pictures of what I need - hope they match what you've had made!

[CJH]

I've sent a file to digits2widgets - it's got 56 of the choke flap parts arranged in one of their smallest containers. I don't expect my first attempt to be exactly hat they need, but I've got the ball rolling at least.

I've started to look at the throttle flap part. It's a much more challenging shape for my fledgling AutoCAD skills. But I'm not convinced that all of the details of the original part are actually needed - some of it appears to be gratuitous styling again. What do people think?

[itchyfeet]

when you design injection moulded parts you create shapes that flow in the mould tool well, alot of the shapes may not be functional to the part but to allow it to be moulded without cold flow and ejected from the tool easily.
I think it has a basic function and you are right alot can be simplified.

[Mocki]

yep i agree, it does not need to be quite so "awkward"
it does need that step up in the bottom for clearance as the fork moves ( thats one of its weak points - well one of mine is broken there)
it is a more challenging bit to remove and replace.

[CJH]

Since this part is broken on one of my spares I'll have a go at dismantling it so that I can take accurate measurements. I'll take care to replicate the bits that seem important, but I do think there's scope to simplify and maybe strengthen the part in places. As for reassembly, tapping for a bolt seems like a good approach. There's very little space below the pushrod for a bolt head or a replacement rivet, but is there perhaps space for a nut on the underside of the forked part, to save tapping a threaded hole? Does the original rivet go right through?

Good news on the file I submitted to Digits2Widgets - they're happy to print it 'as is', and they expect to ship the finished items next Thursday.

[Mocki]

the top bit isnt needed
the step up at the bottom is i think to give clearance when the fork moves ???

yes the "rivit" goes right through, i drilled the inside end off, and then drilled and tapped it M3 after and used a small cabinet screw , but maybe a flat headed bolt would work??

can i preorder three now?
( what are we calling them ? Throttle flap actuators??)

[CJH]

I found the broken parts from my 'parts' carb, and in my case it looks as though the breakage was due to the thinning of the material around the spindle, possibly just through the force of the spring creating friction against the spindle.



So that looks like an obvious area to try and add some more meat. The spindle sleeve can't be thicker all the way down because the spring has to fit over it, but I see no reason why it can't have the same outer diameter as the spring once it gets above the level of the spring. And in fact that's where the two lever parts attach so it makes sense for it to be beefier at that point.

I've had a go at doing the spindle sleeve and one lever. The spring will end up being a fraction more stretched (about 1mm I think) to cope with the thicker sleeve, but I think it can take that.



I'll add the more difficult second lever later.

[Mocki]

yep on further investigation my second one is broken at the spindle too....