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what are stock jet sizes?

fivestring

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I am into renewing a set of Kei Hin carbs (PD42B) and I don't know what size jets are in it.

No known history on the bike. Just bought it and it is very evident someone has had the carbs apart. The airbox and mufflers are gone and I don't know if the carbs were rejetted to run like that or not, I really doubt it.

The carbs were reassembled wrong (two throttles open, two closed) and I have tried cleaning the tops of the jets to get numbers and there simply are no imprints at all on these jets. So,

1. What would be a good starting jet size for running pods and an un-baffled header or open pipes on an otherwise unmodified engine?
2. How many sizes can I go without changing the other jets?
3. Where can I find a good diagram showing proper assembly of these carbs?

Thanks in advance.

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The throttles that you mentioned are actually the choke. And just to be sure you are checking for numbers on the jets in the float bowls right? They are stamped on the sides of the jets. I would start with a #110 or 115 main jet, I would probably start with the #115. These years there actually were jetted to lean from the factory with all the factory exhaust and air box, I think they have like a 105 jet. This should get you running then you need to ride it and see how it acts through all rpms and load ranges. Then go from there with the jetting. I can see what the problem is with the choke linkage, I will try to explain it. In your top picture...the linkage arm on the right carb is on the wrong side of the linkage arm on the left carb. It looks to me like the halve the right shaft turn a half a turn off. Looks like they took the "butterflys" off the shaft because there are screws missing. Also the plates on the left carb is on backwards. The small hole has to be lines up with the brass tube sticking up...that is the accelerator pump nozzle and it needs to be able to spray through the hole. Another thing, they choke should be spring loaded so it is open, you have to pull it closed against spring tension. Looks like previous owner really made a mess of the carbs. I was going to take a picture of my carbs for you to reference off of but my battery died, I will take a picture tonight after work if you need one.
 
Wow! Good info. I sure would appreciate a pic or two.
The main jets I referenced are the ones inside the bowls, screwed on top of emulsion tubes.
Thanks for the help.
 
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Its still kind of hard to see how its supposed to be. yes the pressed in jets are the pilot jets...and they are removable if you are carefull. They should be a #35, I think you may also be seeing a faint Keihin symbol stamp by the number maybe looking like a 1 in front of the 35, they kind of blend in sometimes.
 
I did finally see the jet size. It is very faint but on the side, like you said...

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I have a set of jets including 6 different sizes coming
 
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What happened with this? Did you get it running right? I'm in the same boat since I'm starting with an already modified build. Mine is running, but not running well. What jet size did you end up going with? Open pipes? Mine has a short 4 into 1 with a baffle, but I have no idea what brand it is.
 
govnor what has been done to the motor? What size jets do you have in right now? Early or late style carbs?
 
I'm still working on it govnor.

I put 122 mains in and got it started for the first time today, albeit running pretty rough. I can't get the accelerator pump working and the carbs are back on the bench right now. I will be working more tomorrow on getting the pump to pump. I kept the original pilot jets.
 
The biggest problem I always see with the accelerator pump on these is the check ball and spring in the accelerator pump cover gets stuck. If you are using a new diaphram or have confirmed the old one doesn't leak there is a check valve in the float bowl and in the pump cover. You should be able to check if they work by blowing a little air in the passage. Sometimes you need to soak then blow through and do it a couple of times to free up the check ball and spring. I have had to replace the accel pump cover because I couldn't get the ball free.
 
I had the pump working while holding the fuel bowl in my hand but when I put it on the carb body it isn't delivering. I suspect the oring I used between bowl and carb body is a little too thick. Original oring was long gone so I need to find one a little thinner than this first try. I think it is squishing flat and blocking the passage of fuel to the rest of the carb. All passages in the carb bank are clear and both check valves are working. No tears in diaphragm so I am down to that oring between bowl and body.

I am glad I checked these carbs over closely. Float levels were about 1/4" too low!
 
Yes I have had an o ring that is too thick block off the passage, I completely forgot to mention that. I had a heck of a time trying to find one so in a pinch I took a razor blade and cut the oring thinner so it wouldn't compress as far. I did this as a temporary fix and to see if that is what the problem was. The oring is a smaller than normal diameter o ring.
 
Well after my second attempt at getting the accelerator pump to cooperate, it disintegrated into rubber sediment in the bottom of the housing. Now I will be waiting on a new one to arrive.
 
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