So, now we know this jalopy carb can work.  Time to put the project on hold and see what ThumperLife wants to do.

ThumperLife, do you authorize me to try and fix the idle mixture screw hole in your carburetor body? The stock threads are M6 x 0.5.  I would machine the hole and re-thread to M7 x 0.5.  I already procured the necessary tooling.  There is a risk involved.  I could screw it up and ruin the carb body, but I would do my best to do a good job.  No guarantee, but I would do my best.

Before I start machining the carb body, I will make a custom mixture screw from brass.  The screw will mirror the geometry of a stock OEM screw with the exception that the threaded portion will be M7 x 0.5, and the threads will be a bit longer.  Machining the carb body will be dependent on successful completion of the custom mixture screw.

If the mixture screw and carb body come out well, I will reassemble the carb with my needle jet and needle and run it again to verify that it works correctly.  If it works correctly, you must then purchase a good, genuine Suzuki, OEM needle jet and needle.  No aftermarket stuff, Genuine Suzuki parts only.  It would be best if you had the new parts delivered here so that I can install them in the carb and test.

Piece 11      Needle Jet            09494-00861            (Babbitts lists for $41)
Piece 10      Needle            13383-24C40            (Babbitts lists for $15)


To address the TEV diaphragm, I ordered an aftermarket carb kit from Amazon.  I’m not buying this kit for you, I’m buying it for me.  I’m curious about the kit.  It’s cheap and I want to see what I can learn.  If the TEV diaphragm turns out to be a good part, I will install it in your carb (gratis, my gift to you).  Then I will report on the kit.  Hopefully it will have some useable components.  Either way, we will know if the vendor is a good source.


I will wait for your response.

Looks like you've been busy Mike!

YES. See if you can machine the carb for the mixture screw. I trust it will be fine, and if not, the carb was already not working well last time I had it.

Let me know how that goes, and I will get those other parts ordered.

Another shot of the junk above the needle seat.

Years ago I was sent a carb to fix, and when opened up the entire bowl area looked like a slimy green Forrest of sorts…the worst I’d ever seen.

Used a thread die in the tail stock to cut M7 x 0.5 threads.

I ended up with this.  Not too shabby.  Hopefully I don’t wreck it when I part-off.

Here’s a sketch of the new oversize screw.  For some of you it might come in handy.

The new screw fits nicely, and the action is smooth.  To verify that the screw was seating, I coated the tip with black ink from a Sharpie, then inserted it and ran it all the way home.  ThumperLife, refer to this picture in the future.  It should give you a good idea what the fully seated position looks like.