2cold2ride
New Member
New member here. Forum has been resourceful to me so I thought I should give back. Just want to share an idea with you guys: Idle Mix Screw Mod
Background Story: I have a Mikuni BS36. My screw was stuck in the carb so i had to drill an extractor bit to get it out. Thinking to myself the mix screw is scrapped once i drill into it, I set off to the dealer and web for a replacement; I was out of luck. I searched the forums but could not find a solution either. After seeing some aftermarket adjustible screws (not offered for my carbs), I challenged myself to make one.
What you need:
Idle Mixture Screw (IMS for short)
Brass Screw or Rod (within optimal size of drilled hole on IMS)
Brass Knob
Brazing Equipment (butane torch, metal work flux and solder)
See attachments for reference
1) Learn how to braze and practice. Most important not to get your solder onto the thread of the IMS. Not the end of the world if you get solder onto the threads. Aluminum brush will get it out if solder still hot. Brass is soft so it almost rethread itself during installation.
2) Attach knob to rod. I choosed a screw rod with screw-on knob for ease. But they dont have to have threads; the purpose of this part is to extend the IMS for ease of adjustment. Braze the knob to the rod, or a locking nut works too.
3) Drill your IMS head at center within an acceptable diameter to the brass rod.
4) Braze rod to IMS.
5) Test when cool and enjoy!
Tips: Not as easy as it looks as brazing is a very delicate procedure. Use pliers to hold parts together.
Background Story: I have a Mikuni BS36. My screw was stuck in the carb so i had to drill an extractor bit to get it out. Thinking to myself the mix screw is scrapped once i drill into it, I set off to the dealer and web for a replacement; I was out of luck. I searched the forums but could not find a solution either. After seeing some aftermarket adjustible screws (not offered for my carbs), I challenged myself to make one.
What you need:
Idle Mixture Screw (IMS for short)
Brass Screw or Rod (within optimal size of drilled hole on IMS)
Brass Knob
Brazing Equipment (butane torch, metal work flux and solder)
See attachments for reference
1) Learn how to braze and practice. Most important not to get your solder onto the thread of the IMS. Not the end of the world if you get solder onto the threads. Aluminum brush will get it out if solder still hot. Brass is soft so it almost rethread itself during installation.
2) Attach knob to rod. I choosed a screw rod with screw-on knob for ease. But they dont have to have threads; the purpose of this part is to extend the IMS for ease of adjustment. Braze the knob to the rod, or a locking nut works too.
3) Drill your IMS head at center within an acceptable diameter to the brass rod.
4) Braze rod to IMS.
5) Test when cool and enjoy!
Tips: Not as easy as it looks as brazing is a very delicate procedure. Use pliers to hold parts together.
