Rebuilding my first set of carbs.

[JoshKeast]

Hey everyone, my first post!
Well as the title states, I am rebuilding my first set of carbs on my first motorcycle, an 81 special. A fellow member on here that lives just a few miles from me offered to help but I would kind of like to take this task on myself... a greater sense of satisfaction I guess?

Anyway, I would just like to ask a couple questions, I found rust and some white crusty stuff on the idler jets in 1 and 4 and a white crusty layer in the bowls of 1 and 4. What could cause this in just these two carbs? Numbers 2 and 3 were just kind of oily and sludgy like I would expect.

Question 2, I have read the thread on jetting reccomendations but would still like opinions because I'm get the feeling there is some indifference. I got the bike with Kirker 4 into 1 headers, and since i'm rebuilding the carbs and have the airbox off anyway, I went ahead and drilled it out and bought a K&N air filter for it. Stock main jets are 110's across the board and 42.5 pilots. And now for the question, what jets should I install?

Thanks in advance for all that make it through this long post and offer their advice.

[ddragon63]

Hey everyone, my first post!
Well as the title states, I am rebuilding my first set of carbs on my first motorcycle, an 81 special. A fellow member on here that lives just a few miles from me offered to help but I would kind of like to take this task on myself... a greater sense of satisfaction I guess?

Anyway, I would just like to ask a couple questions, I found rust and some white crusty stuff on the idler jets in 1 and 4 and a white crusty layer in the bowls of 1 and 4. What could cause this in just these two carbs? Numbers 2 and 3 were just kind of oily and sludgy like I would expect.

Question 2, I have read the thread on jetting reccomendations but would still like opinions because I'm get the feeling there is some indifference. I got the bike with Kirker 4 into 1 headers, and since i'm rebuilding the carbs and have the airbox off anyway, I went ahead and drilled it out and bought a K&N air filter for it. Stock main jets are 110's across the board and 42.5 pilots. And now for the question, what jets should I install?

Thanks in advance for all that make it through this long post and offer their advice.

My thought on your white crust in the outer carbs is probably due to the fact the outer 2 are subjected more the world elements... The white stuff is probably dried fuel oxidization. The 2 inner carbs are a little more insulated to the world. This crust is commonly found in dirt bike carbs that sat with a full bowl of gas for too long. Moisture can sweat into the carb and mix with the gas still in the bowl as it evaporates and cause a pasty crusty film.. this could also explain the rust color your seeing, and possibly some greening on the brass parts.

As for the jet sizes I'm sure someone more experienced will chime in and help you out. good luck with your project.

[crazy steve]

I got the bike with Kirker 4 into 1 headers, and since i'm rebuilding the carbs and have the airbox off anyway, I went ahead and drilled it out and bought a K&N air filter for it. Stock main jets are 110's across the board and 42.5 pilots. And now for the question, what jets should I install?

120s across should be very close, you can likely stay with the same pilot jet. But every bike reacts different to mods, so this may only be a starting point. You definitely need bigger mains with that 4-1....

[JoshKeast]

Thanks for the info dragon. That makes me feel a little better knowing it's kind of a common situation.

Crazy Steve, I ordered 120's for all four, I also ordered 45 pilots, the rebuild kit came with 42.5's so i'll be able to flip back and forth if I need to. I just hope I don't have to order 3 other sets of mains to get it right lol...