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Discussion Starter #21
Okay, so this is where I'm currently at and I would definitely be in need of some advice! Two questions:

1. The new one I can screw in, however I'm already stripping the head trying to get it back in. What should I do? Would a "42" be more appropriate and fit better without stripping the head?

2. Which rubber O-ring should I be using? The larger one on the left with a flat side? Or the smaller one on the right with NO flat side?


This is the current state of me trying to install a new slow air jet back in where the old one was extracted by a screw extractor (See the middle):

313698


The old one I took out is labeled as "42", where the new one I got in the latest rebuild kit, is labeled as "35":

313699


The new one I can screw in, however I'm already stripping the head trying to get it back in. What should I do? Would a "42" be more appropriate and fit better without stripping the head?









Secondly, the air mixture screw I got with the new rebuild kit seems slightly different. Which rubber O-ring should I be using? The larger one on the left with a flat side? Or the smaller one on the right with NO flat side?

I have a feeling the current one I have installed, may not be functioning as intended because it doesn't like operating without it being screwed all the way in.

313700
 

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Sensei
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27,144 Posts
Okay, so this is where I'm currently at and I would definitely be in need of some advice! Two questions:

1. The new one I can screw in, however I'm already stripping the head trying to get it back in. What should I do? Would a "42" be more appropriate and fit better without stripping the head? These two jets are OBVIOUSLY not interchangeable just based on mount method...In addition, the #42 jet will flow 44% MORE fuel than the #35 jet ...(OR, the #35 only flows about 69.44% of the required fuel depending on which way you want to look at it).......

2. Which rubber O-ring should I be using? The larger one on the left with a flat side? Or the smaller one on the right with NO flat side? The one closest in size to the tiny washer.......


This is the current state of me trying to install a new slow air jet back in where the old one was extracted by a screw extractor (See the middle):.....The obviously wrong (different) part has likely done irreparable damage already...Replace the carb.....



The old one I took out is labeled as "42", where the new one I got in the latest rebuild kit, is labeled as "35":

View attachment 313699

The new one I can screw in, however I'm already stripping the head trying to get it back in. What should I do? Would a "42" be more appropriate and fit better without stripping the head?..... ANY parts that aren't an exact match should NOT be used........
Feel free to phone me to discuss......










Secondly, the air mixture screw I got with the new rebuild kit seems slightly different. Which rubber O-ring should I be using? The larger one on the left with a flat side? Or the smaller one on the right with NO flat side?

I have a feeling the current one I have installed, may not be functioning as intended because it doesn't like operating without it being screwed all the way in.

View attachment 313700
As above in blue.......
 

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Discussion Starter #23
These two jets are OBVIOUSLY not interchangeable just based on mount method...In addition, the #42 jet will flow 44% MORE fuel than the #35 jet ...(OR, the #35 only flows about 69.44% of the required fuel depending on which way you want to look at it).......
Very good to know, definitely clears things up about the different numbers. Luckily the threads weren’t too bad getting it in. But good to know now that side might be SOL. I figured the threads may have still fit, and it was newer replacement but I guess it was a bad idea.

I ended up ordering press-in’s #42: Replica Keihin Slow Jet - Honda XL350 CB550K CB750 - 1977-1978

The one closest in size to the tiny washer.......
Thank you! I saw some examples online and definitely confirmed this as well. Appreciate the offer of discussing!
 

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Discussion Starter #24
Cool, well now I’m totally fu**ed. Ruined the new carb part I spent $50 on to replace half of the original carb I had. Then proceeded to mess up an extraction with that original carb and now both pieces are ruined! Yay me!

Gotta buy a whole new carb now. Am curious if I need an exact replacement for CB400T thats a VB21B or if there’s a better carb to replace it with that’s compatible.
 

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Discussion Starter #25
Update:

Half carb bought (Right side): Ruined due to jet extraction, screw extractor broke
Original carbs (both left and right): Ruined due to jet extraction

Bought a new set of VB21B carbs on ebay, was planning on not mucking with the pressed in jets this time but then the seller lost half of the carbs that were in the listing... So now I'm stuck with half a left side VB21B carb and a TON of pieces leftover.

Not finding a reliably looking set of VB21B carbs on ebay at this point. I may just purchase a set of Mikuni carbs and call it a day at this point. Only thing that worries me is removal of the airbox and where to put all the things that attach to it. Seems like a whole nother can of worms.
 

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Update:

Half carb bought (Right side): Ruined due to jet extraction, screw extractor broke
Original carbs (both left and right): Ruined due to jet extraction

Bought a new set of VB21B carbs on ebay, was planning on not mucking with the pressed in jets this time but then the seller lost half of the carbs that were in the listing... So now I'm stuck with half a left side VB21B carb and a TON of pieces leftover.

Not finding a reliably looking set of VB21B carbs on ebay at this point. I may just purchase a set of Mikuni carbs and call it a day at this point. Only thing that worries me is removal of the airbox and where to put all the things that attach to it. Seems like a whole nother can of worms.
I’m sorry to hear about all the issues finding replacement carbs. The airbox/filter bits can be figured out.
 

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Discussion Starter #27
Appreciate it, hopefully it’ll only get better from here if I go the mikuni route. Unless I come across another VB21B, or I get the other half from the seller suddenly.
 
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