Oh great guru Dave Dodge can you enlighten us as to what this brass piece in a...


Oh great guru Dave Dodge, can you enlighten us as to what this brass piece in a magna carb does and does it need to come out for cleaning? The end of it appears to be sealed. Thanks!

%d comments
  • hash pipe?

  • Dave may not be able to answer as his computer is down right now. He was getting it fixed

  • Although I'll conceed Mr. Dodge is indeed "the man" since he's temporarily unavailable, I'll answer this one. That's common to both Keihin's and Mikuni carbs, it's part of the choke enrichment circuit. That tube sits in fuel when the float levels are correct, that is... and when you activate the choke, small plungers pull out opening a port which meters a flow of fuel bypassing the low speed circuit and thereby making the mixture conducive to cold starting. Remember, bike's don't use the conventional "choke" like your lawn mower motor does with a butterfly that restricts air to enrich the mixture. In fact, the word 'choke' isn't actually an accurate term. It should be cold-start assist, but choke is more familiar so manufacturers used it. You don't remove it, it's pressed in. Just clean the circuit by taking out the choke plunger on the side, blow some carb cleaner through this circuit and follow with compressed air, it'll be fine. It's not super teeny tiny like the low-speed circuit. I know these carbs quite well, been tinkering on them since the early 80's, shoot me a message if you need more help...

  • Tom thanks for answering this for me/us. I figured I better ask questions on this before I learned the wrong way on it.

  • Thanks for the info Tom M. Batchelor

  • It does not come out, it is were the fuel puddles for passage through the needle. It is cleaned from the top side, through the needle jet. The other fixed jet is the choke jet, and should not be remove. It is towards the rear of the removable slow jet.

  • Dave Dodge thanks for the reply! I think we are all gaining more knowledge. These are a departure from the Holleys, Rochesters, Marvels . Zeniths etc. That I am familiar with.

  • Hey Dave Dodge! Speaking of the "slow jet", any idea what size the orfice is in this? mine is plugged and I have tiny drill bits that I could clean it with. I cannot poke a torch tip cleaner thru it and once I find it after I launched it across the shop with compressed air, I can clean it and put it back in. Thanks for everybody's help!

  • It's about .012". What I do is use a set of jet reamers of assorted sizes, then soak all of the brass jets in CLR which removes the build-up crud. Then I blow through them with spray carb cleaner final clean and double check they all flow.