Author Topic: rebuilding carbs  (Read 16024 times)

Offline taysidedragon

  • SOHC Master
  • Posts: 1787
    • View Profile
Re: rebuilding carbs
« Reply #45 on: April 07, 2026, 08:33:52 PM »
Looks like brand new. 👍
Gareth

1977 CB400F
1965 T100SS

Offline AshimotoK0

  • Grogu
  • *
  • Posts: 7832
  • Mad Scientist.... more power Igor ! Ù©(̾๏̮̮̃̾๏̃̾)Û¶
    • View Profile
Re: rebuilding carbs
« Reply #46 on: April 08, 2026, 06:28:58 PM »
Looks spot on Dave
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline Murf

  • SOHC Member
  • Posts: 249
    • View Profile
Re: rebuilding carbs
« Reply #47 on: April 12, 2026, 10:25:19 AM »
Amazing effort, building a set of ‘as new’ carbs out of a pile of leftovers, what great work.

Offline exvalvesetdabbler

  • SOHC Expert
  • Posts: 414
    • View Profile
Re: rebuilding carbs
« Reply #48 on: April 16, 2026, 02:08:47 PM »
Made a start on reassembling the carb bodies.

Lifter arms showing the felt retainer, shim,spring and cupped washer.
[ Guests cannot view attachments ]

No1 done
[ Guests cannot view attachments ]

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

Offline exvalvesetdabbler

  • SOHC Expert
  • Posts: 414
    • View Profile
Re: rebuilding carbs
« Reply #49 on: April 16, 2026, 02:24:02 PM »
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
[ Guests cannot view attachments ]

Shrunk over a drill bit to keep it straight
[ Guests cannot view attachments ]

Trimmed to size with a scalpel
[ Guests cannot view attachments ]

Regards
Dave

Offline exvalvesetdabbler

  • SOHC Expert
  • Posts: 414
    • View Profile
Re: rebuilding carbs
« Reply #50 on: April 18, 2026, 06:26:24 PM »
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!

[ Guests cannot view attachments ]
[ Guests cannot view attachments ]

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.
[ Guests cannot view attachments ]

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
[ Guests cannot view attachments ]

Regards
Dave
« Last Edit: April 18, 2026, 06:44:40 PM by exvalvesetdabbler »

Offline exvalvesetdabbler

  • SOHC Expert
  • Posts: 414
    • View Profile
Re: rebuilding carbs
« Reply #51 on: April 21, 2026, 06:36:27 PM »
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,

[ Guests cannot view attachments ]
[ Guests cannot view attachments ]
[ Guests cannot view attachments ]

Regards
Dave

Offline K2-K6

  • Grogu
  • *
  • Posts: 5913
    • View Profile
Re: rebuilding carbs
« Reply #52 on: April 22, 2026, 08:30:25 AM »
Very nice work in detail there.

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

Offline Sesman

  • SOHC Master
  • Posts: 2239
    • View Profile
Re: rebuilding carbs
« Reply #53 on: April 22, 2026, 09:32:01 AM »
REet, smart. Nice work.👍.