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Discussion Starter #1
So I had to replace my stock exhaust that was starting to rot pretty good. I didnt want anything too incredibly loud so I ended up finding a pretty good deal on an HMF swamp series. I'm not a big mudder so no snorkeling. I have a dynatek CDI box and a twin air air filter(if that really matters or not). The HMF website says to go with 165 and 155 jets for this but that's with a snorkel. I dont know if the jetting is different if its snorkeled or not but my throttle response is kind crappy. I have 2 washers on my slide needles totalling .045 which is what dynatek said I needed for that. Do I need to change the jetting again? More or less spacing on my needles?
 

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Discussion Starter #2
Fyi...air box cover is on, carbs are secure to the intake and boots are in good shape. Just had the valves a adjusted recently as well
 

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Generally with the Dynatek CDI yes, you will want between .020-.040 shims on the needles. This is about 1/2 a main jet size and helps with the transition off the slow circuit to the main. However as the CDI also adds 5 degrees of spark advance to the ignition even at idle, you "may" also need to go up on the pilot jet from #38 to #40. If she is kind of doggy off idle this may be the problem but if the float levels are on the high end of the range it may not be necessary. As for the muffler, most slip-ons will require a main jet change-usually 1-2 sizes up from stock. Most full systems will require 2-4 sizes up from stock. Remember that the needle shims have already given you a 1/2 size....and never use Dynojet jets, only keihin. And lastly, it's been proven that TwinAir filter media had many direct paths through their media and as such lets small dust particles straight into the engine shortening it's life. You are better off with either the Unifilter or the stock replacements.
 

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Discussion Starter #4
Ok I shouldve mentioned that my pilots are already #40. I'll definitely look at getting new air filter. Other than that what would you suggest I do as far as tuning on that? Throttle is definitly sluggish
 

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Ok I shouldve mentioned that my pilots are already #40. I'll definitely look at getting new air filter. Other than that what would you suggest I do as far as tuning on that? Throttle is definitly sluggish
If you have #40 pilots and it is sluggish right off idle the float levels may already be too high and the #40 are over-fueling it. Still..for the jet change to be effective the float levels must be close to the center of the outlined range. See the manual. And what HMF suggests for mains sounds about right even without snorkels.
 

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Discussion Starter #6
So if I read that right, my next move is to make sure the float is adjusted properly?
 

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So if I read that right, my next move is to make sure the float is adjusted properly?
Well, yes. Step one is always ensure all things are set in the proper working range as outlined in the service manual. Fload levels, valve lash, A/F controls between 2.25-2.50 turns out, compression, fuel supply...ect. And all parts are in good shape like the carb boots, CVT slides and diaphragms, exhaust gaskets...ect.
 

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Discussion Starter #8
My pilot screws were 3 turns out. I'm guessing that might have been part of the problem? Should I go 2.25 or 2.5?
 

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Discussion Starter #12
Well, I dont get it. I still have a slight hesitation like it falls on its face for a split second before it takes off. Everytime i crack the throttle. I have the exact jets that HMF says to have, my air screw is at 2.25 and my intake boots all look good. The only thing i didnt mess with were the floats because, not to sound like an idiot but, I honestly dont understand the process. Maybe I'm reading too far into it or whatever. It just feels like I have a jetting issue still
 

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Well, I dont get it. I still have a slight hesitation like it falls on its face for a split second before it takes off. Everytime i crack the throttle. I have the exact jets that HMF says to have, my air screw is at 2.25 and my intake boots all look good. The only thing i didnt mess with were the floats because, not to sound like an idiot but, I honestly dont understand the process. Maybe I'm reading too far into it or whatever. It just feels like I have a jetting issue still
Might also check that the CV slides work smoothly and the diaphragms are seated correctly and have no holes or splits. You can also force it a little leaner and richer to see if jetting is an issue - leaner-just pop the airbox cover and set something like a folded paper towel in the lower edge just to hold it up slightly..not much. Try it. If worse then put the cover back on and just barely crack the choke..just enough to let a little leak out the port. That will richen it. Those carb boots do crack all the time and almost always where you can't see them..at or under the head-side clamp cause it gets over tightened most times. I went through three sets on mine.


I'm also assuming the valves are set correctly.
 

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IF THE MAIN JETS ARE KEIHIN JETS, I WOULD GO WITH A # 158 FRONT AND A 160 REAR MAIN JET.
THERE ARE TWO WAYS TO CHECK FLOAT LEVELS ON THE CARBS SPELLED OUT IN THE SERVICE MANUAL, I HAVE HAD GOOD LUCK JUST USING THE MEASUREMENT AND NOT DOING THE TUBE LEVEL TEST.
ALSO, YOU CAN SYNC YOUR CARBS PRETTY CLOSE BY USING A WIRE TYPE FEELER GAUGE TO MEASURE THE BUTTERFLY OPENING ON FRONT CARB, THEN SET THE REAR CARB TO THAT FRONT CARB SETTING.
 

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Discussion Starter #15
I'm gonna break into it again here in a little bit. I appreciate all the help you guys give on this page
 

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Discussion Starter #16
Ok I have the air box off and carbs off. I still have the throttle cable and choke cables connected. I removed all 4 boots and inspected those very closely. They're in great shape. The butterflies LOOK like they're set the same. I dont see any gap at all. I also dont have the special tools that the book says I need to check the floats but I'm gonna take the bowls off and see what the floats look like I guess
 

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Discussion Starter #17
IF THE MAIN JETS ARE KEIHIN JETS, I WOULD GO WITH A # 158 FRONT AND A 160 REAR MAIN JET.
THERE ARE TWO WAYS TO CHECK FLOAT LEVELS ON THE CARBS SPELLED OUT IN THE SERVICE MANUAL, I HAVE HAD GOOD LUCK JUST USING THE MEASUREMENT AND NOT DOING THE TUBE LEVEL TEST.
ALSO, YOU CAN SYNC YOUR CARBS PRETTY CLOSE BY USING A WIRE TYPE FEELER GAUGE TO MEASURE THE BUTTERFLY OPENING ON FRONT CARB, THEN SET THE REAR CARB TO THAT FRONT CARB SETTING.
My jets ARE Keihin jets. So I guess I'll run and get a 158 and 160 and try that as well. Just for shits and giggles when I get it back together
 

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Honda dealers are known to carry the jets we use for our carbs in Keihin brand jets.
As for the floats, I check the measurements from the bowl mounting flat edge to the float - I think it is supposed to be like 2 - 3 mm gap roughly.
 

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Discussion Starter #20
So after making a trip I bought a jet. However, i talked to the mechanic at the shop and i think i found the problem or at least part of...and the problem I've been having for over 4 years now. There is a little tiny brass "thingy" circled in the picture. It's on the little part that sticks out on the vacuum slide seal. I believe it's called a "jet air leak". Each carb has one. Except, one of mine is missing. From what I understand that could be the culprit of my issue and my hard starting issue and bad throttle response since I bought the machine
 

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