No parts today. Maybe tomorrow. You all get a break from me today..thats a jab at myself threre!! I do feel m och more confident that I can get these things back on track very shortly though.
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Carb mechanic wanted
- Thread starter chuck hahn
- Start date
S
Spyderman
Guest
hi chuck how about some info for you on the carbs and how they work
the three circuits of the carbs
1 the pilot circuit from 0 to 1/4 throttle
stock pilot jet size 15
this is controlled by the pilot jet the fuel mixture screw on the bottom of the carb and the air mixture screw on the side of the carb
settings for the 77 750 i had
5/8 to 7/8 of a turn (fuel screws) bottom of the carb
1 1/2 to 1 3/4 for the (air screws) side of the carb
the needle and needle jet circuit from 1/4 to 3/4 throttle
this is controlled by the movement of the needle up and down in the needle jet the fuel is metered by the taper of the needle
the clip position and the size of the needle jet
5F21-3 is the stock needle with a position of 3rd from the top for the clip
O-6 this is the stock needle jet O-6 is the size for diameter
( the jet needle is the tube that unscrews from the carb with a 8mm wrench and the main jet screws into to it on one end)
this circuit can be affected by the size of the main jet if the main jet is too big then it will be rich on this circuit as well
if it is too small then this circuit will be lean as well
and the clip position will affect how fast or slow the fuel flows into the carb on this circuit (closer to the taper of the needle will richen the mixture closer to the top of the needle will lean the mixture)
the main jet circuit from 3/4 to wide open throttle
stock main jet size is 100
this circuit is controlled my the main jet only so size is important to get correct
now in order to know what to change you need to know how to read your plugs
the end of the plug will tell you what your pilot circuit is doing
looking down the center electrode from the top down to the bottom of the plug
from the top to about 1/2 way down will tell you what your needle circuit is doing
from 1/2 down to the bottom will tell you what your main jet is doing
you want the plugs to be a nice tan color all the way down the center electrode when the jetting is right
when you rejet your carbs you start with the main jet then once this is right you move onto the needle and once you have that right you do the pilot
plug chops
you need to go out and ride it pull a plug read it and make one change then ride it and read the plug again do this until you have it right
in order to get a good reading on each circuit you must ride it at the specified throttle setting for about 3/4 of a mile and then hit the kill switch then release the throttle then stop the bike and pull a plug and read it
i'm sure you are familiar with doing plug chops
i hope i have helped to to better understand your carbs
the three circuits of the carbs
1 the pilot circuit from 0 to 1/4 throttle
stock pilot jet size 15
this is controlled by the pilot jet the fuel mixture screw on the bottom of the carb and the air mixture screw on the side of the carb
settings for the 77 750 i had
5/8 to 7/8 of a turn (fuel screws) bottom of the carb
1 1/2 to 1 3/4 for the (air screws) side of the carb
the needle and needle jet circuit from 1/4 to 3/4 throttle
this is controlled by the movement of the needle up and down in the needle jet the fuel is metered by the taper of the needle
the clip position and the size of the needle jet
5F21-3 is the stock needle with a position of 3rd from the top for the clip
O-6 this is the stock needle jet O-6 is the size for diameter
( the jet needle is the tube that unscrews from the carb with a 8mm wrench and the main jet screws into to it on one end)
this circuit can be affected by the size of the main jet if the main jet is too big then it will be rich on this circuit as well
if it is too small then this circuit will be lean as well
and the clip position will affect how fast or slow the fuel flows into the carb on this circuit (closer to the taper of the needle will richen the mixture closer to the top of the needle will lean the mixture)
the main jet circuit from 3/4 to wide open throttle
stock main jet size is 100
this circuit is controlled my the main jet only so size is important to get correct
now in order to know what to change you need to know how to read your plugs
the end of the plug will tell you what your pilot circuit is doing
looking down the center electrode from the top down to the bottom of the plug
from the top to about 1/2 way down will tell you what your needle circuit is doing
from 1/2 down to the bottom will tell you what your main jet is doing
you want the plugs to be a nice tan color all the way down the center electrode when the jetting is right
when you rejet your carbs you start with the main jet then once this is right you move onto the needle and once you have that right you do the pilot
plug chops
you need to go out and ride it pull a plug read it and make one change then ride it and read the plug again do this until you have it right
in order to get a good reading on each circuit you must ride it at the specified throttle setting for about 3/4 of a mile and then hit the kill switch then release the throttle then stop the bike and pull a plug and read it
i'm sure you are familiar with doing plug chops
i hope i have helped to to better understand your carbs
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I followed all that except the start on the main..then the needle and then the pilot..you mean doing the plug chops..right> So if i run it and pull a plug and the first section of the electrode like you said is tannish that means the MAIN JET is the proper jet . Then the second part will read what the NEEDLE JET is doing..right so its basically like looking at a layer cake as far as the plugs are concerned.
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What are you saying is the TOP of the plug..the end near the square the wrench grabs or am i looking at the top as in from the spot where the spark jumps across?
S
Spyderman
Guest
ok so doing plug chops you start with the main jet and your looking at the bottom 1/2 of the center electrode if it is a nice tan color then your fine if it's white then your too lean and if it's black then your too rich
when the main jet is right (good tan color)
then move onto the needle circuit this is mostly done by moving the clip position once this is right then move on an do the pilot circuit
and yes it's like a layer cake the top is the pilot circuit
the middle is the needle circuit and the bottom is the main circuit
S
Spyderman
Guest
i mean the top of the plug is the end the spark jumps across
OK so by TOP i am looking at the two electrodes.. If you lay a plug in my hand and ask me which end is the top i will point at the end the wire hooks to but thats not what you mean..
S
Spyderman
Guest
right i mean the top of the plug is the other end from where the wire connects to
i got it..thats where i get twisted. I literally take what you guys type and then i am wrong and all twisted around. I get it now.. thanks.
S
Spyderman
Guest
no problem at all
now remember that each circuit is controlled by throttle position and not speed on your speedo or by RPM on your tach neither speed or RPM affect what a carb does on any of the circuits
only throttle position controls what each circuit does
now remember that each circuit is controlled by throttle position and not speed on your speedo or by RPM on your tach neither speed or RPM affect what a carb does on any of the circuits
only throttle position controls what each circuit does
S
Spyderman
Guest
also i hope that you noticed that i gave you the stock jet sizes and needle and needle jet size for your carbs
and the settings for the pilot fuel screws and air screws are just a starting point you may need to fine tune them to get it perfect
also remember that those screws will be different for each carb that is why you need to do the plug chops
for example carb #1 could be @ 5/8 of a turn out #2 @ 3/4 #3 @ 5/8 and #4 @ 7/8
your plug for each cylinder will tell you where you need to set the screws
again i hope i have helped you to get a better grip on getting your carbs set up right
and the settings for the pilot fuel screws and air screws are just a starting point you may need to fine tune them to get it perfect
also remember that those screws will be different for each carb that is why you need to do the plug chops
for example carb #1 could be @ 5/8 of a turn out #2 @ 3/4 #3 @ 5/8 and #4 @ 7/8
your plug for each cylinder will tell you where you need to set the screws
again i hope i have helped you to get a better grip on getting your carbs set up right
S
Spyderman
Guest
good sunlight and a magnifying glass will do it works for me
i was already thinking of the mag glass..
330 Texas time..I just got home to find the jets from Z1 in the mail..I wll be tearing these carbs down and i will post all the numbers i find on the parts..then we can assemble from there...
OK..so heres what i have for numbers
Cutaway at the bottom of the slides is 1.5
The needle jets that are in it are 5F21 and the clips are on the ctr groove
The emulsion tubes i couldnt find any number on them.
So heres my plan of attack..I am gonna put in the 100 main jets, the 15 pilot jets, spray everything down with carb cleaner and compressed air and poke out all the little holes to be sure they are open, and reassemble....sound reasonable???
Cutaway at the bottom of the slides is 1.5
The needle jets that are in it are 5F21 and the clips are on the ctr groove
The emulsion tubes i couldnt find any number on them.
So heres my plan of attack..I am gonna put in the 100 main jets, the 15 pilot jets, spray everything down with carb cleaner and compressed air and poke out all the little holes to be sure they are open, and reassemble....sound reasonable???
I have done the following..
Installed the new 100 mains and the new 15 pilot jets
verified the correct needle jets were in the carbs they were ..5F21
verified all the clips were in the 3rd groove.
I recleaned all the holes in the emullsion tubes and took out all the pilot jets to be sure the needle ends werent damaged and to spray carb cleaner thru them as well
did the same with the air screws and passages.
After poking and carb dleaner sraying i blew comoressed air thru all passages.
verified all the float heights as per Rustybroncos instructions.
verified the little sringy thing on the float valves werent stuck
set the pilot screws at 7/8 out and the air screws at 1 1/2 out.
reassembled and installed on the bike. She fired right up and i almost immediately noticed the difference in idle smoothness and theought ..heyn this is a good sign. Next i stuffed my pockets with tools and took it out on the freeway. I decided i woul ride till i found an exit and do a plug chop and just get over as far as i could from traffic. I checkd the plugs and they a looked ok to me and just a bit of tan about 1/16 to 1/6 up the porcellan from the electrodes. I adjusted the air screws IN 1/8 turn and took it for another ride. now they are a bit more tan but way from being blackened, so i figure i am real close. I then took it back mout again and tried to ride it like i stold it. It has way more response now and really wants to pull..MUCH MUCH MUCH different than what it was acting like before!! I was going 75 in 5th gear and just turned the throttle a bit more open and it didnt couch or anything. It just started climbing out as i would expect it to do. Thats the good news..now the bad. I got 3 more bikes that i want to be sure are set up accordingly..I was very intimidated and confused as to what you all were trying to explain but it is abit less confusing now and i want to say thanks to all of you, even though i must have had a lot of you really frustrated with me. So here is the final set up as it sits right now::
100 main jets
15 pilot jets
pilot jet screws out 7/8
air screws out 1 3/8
5F21 needle jets clip on center groove.
Installed the new 100 mains and the new 15 pilot jets
verified the correct needle jets were in the carbs they were ..5F21
verified all the clips were in the 3rd groove.
I recleaned all the holes in the emullsion tubes and took out all the pilot jets to be sure the needle ends werent damaged and to spray carb cleaner thru them as well
did the same with the air screws and passages.
After poking and carb dleaner sraying i blew comoressed air thru all passages.
verified all the float heights as per Rustybroncos instructions.
verified the little sringy thing on the float valves werent stuck
set the pilot screws at 7/8 out and the air screws at 1 1/2 out.
reassembled and installed on the bike. She fired right up and i almost immediately noticed the difference in idle smoothness and theought ..heyn this is a good sign. Next i stuffed my pockets with tools and took it out on the freeway. I decided i woul ride till i found an exit and do a plug chop and just get over as far as i could from traffic. I checkd the plugs and they a looked ok to me and just a bit of tan about 1/16 to 1/6 up the porcellan from the electrodes. I adjusted the air screws IN 1/8 turn and took it for another ride. now they are a bit more tan but way from being blackened, so i figure i am real close. I then took it back mout again and tried to ride it like i stold it. It has way more response now and really wants to pull..MUCH MUCH MUCH different than what it was acting like before!! I was going 75 in 5th gear and just turned the throttle a bit more open and it didnt couch or anything. It just started climbing out as i would expect it to do. Thats the good news..now the bad. I got 3 more bikes that i want to be sure are set up accordingly..I was very intimidated and confused as to what you all were trying to explain but it is abit less confusing now and i want to say thanks to all of you, even though i must have had a lot of you really frustrated with me. So here is the final set up as it sits right now::
100 main jets
15 pilot jets
pilot jet screws out 7/8
air screws out 1 3/8
5F21 needle jets clip on center groove.
One question still remains... Did you bench sync them as I suggested?
yes..i left a message cuz i knew you were doing the floor trim... I set them looking from the engine side..just a guess that it was what you meant. just a sliver in number 1 and then set 2 thru 4 to lokk exactly like number 1.
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