rebuilding carbs

[taysidedragon]

Looks like brand new. 👍

[AshimotoK0]

Looks spot on Dave

[Murf]

Amazing effort, building a set of ‘as new’ carbs out of a pile of leftovers, what great work.

[exvalvesetdabbler]

Made a start on reassembling the carb bodies.

Lifter arms showing the felt retainer, shim,spring and cupped washer.
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No1 done
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It was a bit fiddly getting the fast idle cam installed, trying  not to loose the tiny spring and ball bearing that indexes the cam in the choke upen position.

I have hit one snag so far, one of the choke flap rods won't fit. I suspect that it was in a batch of plating where I dozed off and it was plated for over an hour. It will have to be stripped and redone.

Regards
Dave

[exvalvesetdabbler]

A solution to the breather interconnector tubes.  The old ones had to be sliced off with a scalpel.

I had some offcuts of  viton tube in various sizes (skip find that I thought could come in handy one day) which is a bit soft compared to the originals.  Then it came to me, use an outer sleeve of heat shrink to stiffen it up a bit.

Outer sleeve of heat shrink over viton tube
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Shrunk over a drill bit to keep it straight
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Trimmed to size with a scalpel
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Regards
Dave

[exvalvesetdabbler]

Time to make some gasgets for the carb top covers.  After a few practice runs using the side of a serial box I was left with some functional but rather ugly gasgets. Even with the smallest of curved nail scissors, cutting the inside radius was never going to be easy.

Below is what I came up with using flexoid gasget paper.

First thing is to mark out the screw holes.  I made a 'cookie cutter' the exact size to slip through the actual holes in a top cover to mark their position.  I then taped an OEM gasget onto the gasget paper sheet and so that the holes lined up.  I was then able to draw around the inside of the OEM gasget.

Using a cookie cutter I could then cut out all of the inside curves and then use a scalpel to cut the straight sections. The large cutter was a roll bar bush collar from a ford Sierra. Been in the 'come in handy box'  all this time and it came in handy!

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Next I screwed the top cover to a piece of plywood sandwiching the gasget paper. Then used the cutter to cut out the inside radius on the outside.
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Then using a  scalpel I was able to cut the remainder of the outside profile using the top cover as a guide

Spot the difference
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Regards
Dave

[exvalvesetdabbler]

Time to see if everything fits together after having to strip and replate one of the choke rods and a few screws that ended up over size while I was sleeping on the job. This is just a test fit. Fuel connectors and sync adjusters still need fitting.

Installed the new gasgets on the top covers and just before that I bent over the tab washers on the lifter arms.  Shouldn't need to go in there any more. Refitted the choke flaps.

Next job is to sort through the brass ware and see what I have or haven't got.  Also need to find the  o rings and drain screws for the float bowls.  I have tried measuring an OEM o ring and can't decide if it's 63,4 or 5 ?  Some advice on how to fit these would be appreciated since they are no longer shaped to fit the bowls. I guess some glue might be needed in strategic places.

For the drain screws I haven't decided whether to try making some or take a punt with those on AliExpress. All comes down to being able to cut the screwdriver slot and make a neat job of it.

Here's where we are at the moment,

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Regards
Dave

[K2-K6]

Very nice work in detail there.

Hopefully you'll get the deserved running accuracy in response too.

[Sesman]

REet, smart. Nice work.👍.

[exvalvesetdabbler]

63 x 1.8 seems to fit ok

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Regards
Dave

[exvalvesetdabbler]

Drain screws from AliExpress

O ring seat 9 mm, screw head 9.4mm
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Might work if there's nothing else but doesn't look right.  Back to plan b for these.
Regards
Dave

[Oddjob]

Fairly sure there was a seller of these on eBay but they weren’t exactly cheap

[exvalvesetdabbler]

The problem with them screws is that there is very little contact area between the screw head and the carb body, essentially a ring 0.2 mm around the screw head making contact and no friction as you tighten them which in the wrong hands could easily result in stripped threads or them working loose.

A heads up for anyone else thinking of buying these, check that the head diameter 12mm.  I didn't loose much with these ay £3.50 for 2 , I just added a couple onto an existing order get above the free postage threshold.

NRP have the Keyster ones back in stock now at just over a fiver each.  Might have to bite the bullet. I'll hold off for now until I have sorted through all the spare brassware to see what else I might need.

Does anyone have any good tips for cutting neat screw slots, I have seen something somewhere about folk grinding the set off a hacksaw blade to get the right thickness?  Machining the threads and holes be easy enough and I have enough round brass bar laying around.

Regards
Dave

[K2-K6]

The problem with them screws is that there is very little contact area between the screw head and the carb body, essentially a ring 0.2 mm around the screw head making contact and no friction as you tighten them which in the wrong hands could easily result in stripped threads or them working loose.

A heads up for anyone else thinking of buying these, check that the head diameter 12mm.  I didn't loose much with these ay £3.50 for 2 , I just added a couple onto an existing order get above the free postage threshold.

NRP have the Keyster ones back in stock now at just over a fiver each.  Might have to bite the bullet. I'll hold off for now until I have sorted through all the spare brassware to see what else I might need.

Does anyone have any good tips for cutting neat screw slots, I have seen something somewhere about folk grinding the set off a hacksaw blade to get the right thickness?  Machining the threads and holes be easy enough and I have enough round brass bar laying around.

Regards
Dave

Something like this https://www.ebay.co.uk/itm/336154261880 available in 0.5mm thickness, but would need rudimentary mount to drill etc and some method of holding brass bar and moving across this, thinking lathe cross slide and dremel  ?

A woodworking mortise hand saw will cut brass more accurately than trying to hold a hacksaw blade straight enough, could be utilised.

[exvalvesetdabbler]

I have slitting saw, but at the moment I'm only set up to mount it on an arbour  between centers and used to cut hexagon on the end of round bar held in the tool post. I might need someway to get up/down movement. I could just cut the slot  to limited depth which would be curved same as the saw radius and then just flatten out the slot with small file.

Dave.