Help,need jetting help old big red
Apr 19, 2008 | 11:22 PM
#1
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Trailblazer
Joined: Apr 2005
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Help,need jetting help old big red
My dad has a old (1982) Big Red that he putzes around on and he is having a terrible time fouling plugs. It has a 90 main in it now,,how lean could we safely go. I have the clip the whole way on top groove. Also,the air mixture screw,I assume turned out is leaner. Any help much appreciated.
Apr 20, 2008 | 01:16 AM
#2
Elite Pro Rider
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Help,need jetting help old big red
Out is richer, on mixture screws.
Does it burn oil? Hows the compression?How dirty is the air filter? Float level check out ok?
Id go to an Iradium spark plug, before going leaner on the main jet. They are designed to resist fouling much more than standard plugs.
The needle jet is set at the leanest when the clip is at the top...id go back to the center.
Does it burn oil? Hows the compression?How dirty is the air filter? Float level check out ok?
Id go to an Iradium spark plug, before going leaner on the main jet. They are designed to resist fouling much more than standard plugs.
The needle jet is set at the leanest when the clip is at the top...id go back to the center.
Apr 20, 2008 | 08:48 PM
#3
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Trailblazer
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Help,need jetting help old big red
Not to question your wisdom,,but out is deffinetly richer on air screw. It seems to not burn oil,,like I said,it is my dads and it gets run very seldom. Air filter is clean,compression is good,float seems ok,what Iradium plug should we go with. It currently has a NGK dr9es in it. You can go a couple hundred yards and the plug is black. I know the air screw was 2 1/2 turns out,he thought that out was leaner.
Apr 20, 2008 | 09:33 PM
#4
Range Rover
Joined: Feb 2008
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Help,need jetting help old big red
I have 2 84 200es big reds that had the exact same problem. All i did was adjust the pilot screw and leaned them out some. I would go through 1 plug per week of ridding. I haven't had to change a plug since then and this was done over a year ago.
Apr 20, 2008 | 10:43 PM
#5
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Help,need jetting help old big red
<div class="FTQUOTE"><begin quote>Originally posted by: mrtool2u
Not to question your wisdom,,but out is deffinetly richer on air screw. It seems to not burn oil,,like I said,it is my dads and it gets run very seldom. Air filter is clean,compression is good,float seems ok,what Iradium plug should we go with. It currently has a NGK dr9es in it. You can go a couple hundred yards and the plug is black. I know the air screw was 2 1/2 turns out,he thought that out was leaner.</end quote></div>
Its a 4 stroke, which 99% are mixture screws. If the screw is between the slide and the cylinder head....its a mixture screw.
If its between the slide and the air filter....its an air screw.
And on air screws....out is leaner.(just the opposite of mixture screws)
Make sure all the components are on the mixture screw..spring, steel washer, and o ring.
Not to question your wisdom,,but out is deffinetly richer on air screw. It seems to not burn oil,,like I said,it is my dads and it gets run very seldom. Air filter is clean,compression is good,float seems ok,what Iradium plug should we go with. It currently has a NGK dr9es in it. You can go a couple hundred yards and the plug is black. I know the air screw was 2 1/2 turns out,he thought that out was leaner.</end quote></div>
Its a 4 stroke, which 99% are mixture screws. If the screw is between the slide and the cylinder head....its a mixture screw.
If its between the slide and the air filter....its an air screw.
And on air screws....out is leaner.(just the opposite of mixture screws)
Make sure all the components are on the mixture screw..spring, steel washer, and o ring.
Apr 21, 2008 | 12:44 AM
#6
Pro Rider
Joined: Feb 2004
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From: Bismarck North Dakota
Help,need jetting help old big red
The problem with the old big red is not jetting.
The needle jet and jet needle need replacement.
After years of use, the brass components wear from the needle rattling around.
Go to your Honda dealer and have them sell you a needle jet set.
The carb will have to come apart to replace the needle jet as it rides under the main jet emulsion tube. When installing, make sure the thin walled side is inserted towards the carb bore. The jet needle is easy to remove as it simply slips into the throttle slide under the spring and plate.
Later year units have aluminum needles that fit the slide better and will not shatter out.
----- Gimpster -----
The needle jet and jet needle need replacement.
After years of use, the brass components wear from the needle rattling around.
Go to your Honda dealer and have them sell you a needle jet set.
The carb will have to come apart to replace the needle jet as it rides under the main jet emulsion tube. When installing, make sure the thin walled side is inserted towards the carb bore. The jet needle is easy to remove as it simply slips into the throttle slide under the spring and plate.
Later year units have aluminum needles that fit the slide better and will not shatter out.
----- Gimpster -----
Apr 21, 2008 | 09:46 AM
#7
Range Rover
Joined: Mar 2008
Posts: 169
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Help,need jetting help old big red
<div class="FTQUOTE"><begin quote>Originally posted by: Gimpster
The problem with the old big red is not jetting.
The needle jet and jet needle need replacement.
After years of use, the brass components wear from the needle rattling around.
Go to your Honda dealer and have them sell you a needle jet set.
The carb will have to come apart to replace the needle jet as it rides under the main jet emulsion tube. When installing, make sure the thin walled side is inserted towards the carb bore. The jet needle is easy to remove as it simply slips into the throttle slide under the spring and plate.
Later year units have aluminum needles that fit the slide better and will not shatter out.
----- Gimpster -----</end quote></div>
I agree with Gimpster - BUT - you can get a whole aftermarket carb kit (with everything but the float) for less than the cost of the 2 components from your dealer ($38 honda needle jet set vs. $15-20 for Keyster, Shindy, Armor Tech complete kit). Ebay or your Local independent ATV repair shop will be your best bet.
The problem with the old big red is not jetting.
The needle jet and jet needle need replacement.
After years of use, the brass components wear from the needle rattling around.
Go to your Honda dealer and have them sell you a needle jet set.
The carb will have to come apart to replace the needle jet as it rides under the main jet emulsion tube. When installing, make sure the thin walled side is inserted towards the carb bore. The jet needle is easy to remove as it simply slips into the throttle slide under the spring and plate.
Later year units have aluminum needles that fit the slide better and will not shatter out.
----- Gimpster -----</end quote></div>
I agree with Gimpster - BUT - you can get a whole aftermarket carb kit (with everything but the float) for less than the cost of the 2 components from your dealer ($38 honda needle jet set vs. $15-20 for Keyster, Shindy, Armor Tech complete kit). Ebay or your Local independent ATV repair shop will be your best bet.
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Apr 22, 2008 | 10:16 AM
#10
Range Rover
Joined: Mar 2008
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Help,need jetting help old big red
snorulz, Your "fix" was probably fine for your situation - what you did was adjust your idle circuit fuel flow to compensate for the wear on the needle and jet that was allowing a little "extra" fuel. Mrtool2u had already dropped his needle as far as it would go, indicating the total wear on the needle jet set.