I've got air flowing freely between the adjustment port, fuel side, and the three holes in the carb body, but can't get anything through the air intake, the hole under the diaphragm. I can see a brass plugs in both carbs with no hole in it. There doesn't appear to be any hole(s) around them. That is confusing. Repeated, as in three days worth, soaking with carb cleaner and blowing air at 20 psi isn't getting me anywhere. Advice please.
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Need Help with BS34 pilot circut cleaning.
- Thread starter Jim May
- Start date
I don't understand what it is your referring to. Need a picture.
I refer to the small circular hole in the lower left of the photo. I have read that the brass item at the bottom of the hole is an air pilot passage. I see no small hole in either of the brass items in either carb. What am I not seeing or understanding. Thanks for the help.
You have it half right. Yes, that is a plugged hole. It was drilled to create part of a passage further down the carb body, and then a plug was put in the top of the hole. No, it is not an air pilot orifice. All is good with your carb.
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Jim are you familiar with the carb guide?
http://www.amckayltd.com/carbguide.pdf
I stole/copied this from there.
"In the back of the BS34 (80-83) you will find four round holes (see Appendix, item 6). The upper pair (below curved diaphragm chamber vent) vent the carb body above the floats. Below those are the air jets. The pilot air jet is removable, and the main air jet is fixed."
http://www.amckayltd.com/carbguide.pdf
I stole/copied this from there.
"In the back of the BS34 (80-83) you will find four round holes (see Appendix, item 6). The upper pair (below curved diaphragm chamber vent) vent the carb body above the floats. Below those are the air jets. The pilot air jet is removable, and the main air jet is fixed."
Thanks for the help. The Carb Guide leads me to believe that air passes through this hole to a passage that leads into the carb throat. Guess I didn't (still don't) understand what was written. Are one of the three holes in the carb body, the ones near the throttle plates, the pilot air holes?
Those are pilot feed to the throttle body. The pilot air intake is in the intake bell.
Maybe I don't understand what you are asking.
Gas flows through the pilot jet to the three triangle-arranged holes in the throat. Connected to this same pilot jet circuit is another hole in the throat forward of the three triangle holes. The flow of gas through that hole is adjustable by the long brass screw with the pointed tip at the front top of the carb. This brass screw is commonly and erroneously called the "air mix" screw, but there is no air involved. From the factory there was a solder(?) plug over the air mix screw, you have to remove the plug before you can access the screw, this is explained in the Carb Guide.
If you study the outside of the carb body, you can pretty much follow how passages were drilled into the cast body to connect with other drilled passage holes, and then the entrances to the drilled holes were plugged with brass balls, leaving only the intended passages and orifices..
If you study the outside of the carb body, you can pretty much follow how passages were drilled into the cast body to connect with other drilled passage holes, and then the entrances to the drilled holes were plugged with brass balls, leaving only the intended passages and orifices..
Understand what you are saying. The factory plugs were removed by someone in the past and the right side adjustment screw had been closed. The left side plug was black so I assume that the bike had been idling on the left side cylinder. I'm going to be certain that there are no obstructions in the three 'triangle holes' before I put the carbs back on the bike and check operation. Thank you for your time and help.
Thank you for the help. I was TOTALLY confused by the mention of the hole in the diaphragm chamber. Others also made the same mistake and tried to open a passage that isn't there at all. Again, Thanks.
Carbs are on and I followed the tune up guide and it runs fine. Will post a question about an improperly seated front tire. Thanks for all the help.
