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Carb Cleaning 101

140K views 124 replies 65 participants last post by  roadieforlifeok  
#1 ·
I wanted to document my carb tear-down, in case anyone wanting to do this with/without the manual could do so pretty easily. I will also have this in Word format to e-mail out to anyone needing it. I did a search for this and didnt find anything like it on the board. It might be somewhere else, though, so if I duplicated the effort, I apologize in advance. The steps are quoted directly from the manual, and anything I add will be highlighted in red. The first steps involve other procedures I did not document...this is strictly getting just the carb off and tearing it down.

Step 1: Drain the coolant.
** This involves taking the tank off, which I already had off anyway.
** You do not necessarily need to drain the coolant, but you will have to burp the air out of the system when everything is reconnected.

Step 2: Remove the right front cylinder head shroud (top fins).

Step 3: Remove the air cleaner housing (or aftermarket air kit).

Step 4: Disconnect the fuel hose from the carburetor.

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Step 5: Slide the rubber cap off the starting enrichment (SE) valve nut.

Step 6: Loosen the SE valve nut and remove the SE valve from the carburetor.
** It helped to take the choke knob off it's holder on the pet****-side, which I did.

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Step 7: Disconnect the throttle position sensor connector.
** It's the white connector that is next to the neck of the frame...you can't miss it. It's already unplugged in the following picture.

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Step 8: Remove the throttle cables from the cable stay and disconnect them from the throttle drum.
** I'll get a picture of this when I put the carb back together...forgot to snap one during the tear-down.

Step 9: Disconnect the vacuum hose from the carburetor.

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Step 10: Loosen the carburetor insulator band screw and remove the carburetor from the insulator.

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Step 11: Disconnect the water hoses from the carburetor and remove the carburetor.

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Step 12: Seal the intake manifold port with tape or a clean cloth to keep dirt and debris from entering the engine.

Step 13: Remove the three screws attaching the throttle position sensor and carburetor heater.
** Don't jack with the Torx screw.

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Step 14: Remove the throttle position sensor with its bracket.

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Step 15: Remove the connector joint from the throttle.

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Step 16: Remove the carburetor heater setting plate.

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Step 17: Remove the carburetor heater from the carburetor body.

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Step 18: Remove the O-rings from the carburetor heater.
** I used a small Craftsman pick to gently pry them up and off.

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Step 19: Remove the four screws while holding the vacuum chamber cover.

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Step 20: Remove the vacuum chamber cover, compression spring and diaphragm/vacuum piston from the carburetor body.

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Step 21: Turn the needle holder counterclockwise by using a screwdriver while pressing it in and release the holder flange from the vacuum piston. Remove the needle holder, spring & jet needle.
** I use an 8mm long socket with an extension on the yellow needle holder...mainly because I stripped the Phillips screw a long time ago when I was a noob. Also, I have a DynoJet Stage 3 jet kit, so my parts will look slightly different than the stock setup.

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This is the infamous "tit" that gets clipped when doing a rejet, if you have to shim your stock needle or use a different needle from a kit.

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The small spring screws onto the "tit". Be careful when taking it off/putting it back on that you don't stretch it out of shape.

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Here's the order of putting the DJ stuff back together. The e-clip is in the 4th groove from the top of the needle, then the washer sits on top of the e-clip, then the head of the needle goes into the spring.

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For the stock parts, the stock needle (shimmed with washers underneath the head - Scar Mod) goes into the diaphragm/vacuum piston, then the spring sits on top of the stock needle's head.

Here's a picture of a stock needle (top) and a DynoJet needle (bottom). Since the stock needle has no grooves, the Scar Mod washers must go underneath the head of the needle. This achieves the same results as moving the e-clip on the DynoJet needle. Also, notice that the two needles differ in their tapering.

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Step 22: Check the jet needle for stepped wear. Check the vacuum piston for wear or damage. Check the diaphragm for pin holes, deterioration or other damage. Check the vacuum piston for smooth operation up and down in the carburetor body. Air will leak out of the vacuum chamber if the diaphragm is damaged in any way, even with just a pin hole.

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Step 23: Remove the two screws and washers while holding the air cut-off valve cover.

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Step 24: Remove the air cut-off valve cover, spring and diaphragm from the carburetor body. Check the diaphragm for pin holes, deterioration or other damage. Check the diaphragm rod for wear or damage at the tip. Check the orifice in the valve cover and carburetor body for clogs or restrictions.

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Step 25: Remove the three screws and washers while holding the accelerator pump cover.

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Step 26: Remove the accelerator pump cover, spring and diaphragm/rod from the float chamber. Check the diaphragm for pin holes, deterioration or other damage.
** As you can see, my rod is severely corroded. :shock: I used some 1500-grit sandpaper to clean it up, but I may just go ahead and order a replacement for good measure. Guess I wore out my accelerator pump, probably because my bike is orange! :mrgreen:

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Step 27: Check the pump rod boot for deterioration or damage (small rubber boot in above picture - looks like an accordian).
** Gently pull the pump rod boot apart in good lighting to check for holes or tears.

Step 28: Remove the bolt, plastic washer, accelerator pump link, collar, plain washer and spring (lock) washer from the float chamber.
** I used an 8mm socket on that bolt - much easier to break loose.

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Step 29: Remove the four screws and the float chamber.

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Step 30: Remove the float pin, float and float valve. Check the float for damage or fuel in the float.
** I used that same Craftsman pick to push the pin on one end so I could get it out on the other end.

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Step 31: Check the float valve and valve seat for scoring, scratches, clogs or damage. Check the tip of the float valve, where it contacts the valve seat, for stepped wear or contamination. Check the operation of the float valve.

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Step 32: Remove the following:
- Main Jet (mine is a 210 - used flat screwdriver)
- Needle Jet holder (used 7mm long socket)
- Needle Jet (used Craftsman pick to push it out)
- Slow Jet (also called pilot jet - used flat screwdriver)

Check each jet for wear and damage. Clean the jets with cleaning solvent and blow open with compressed air.

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Main jet screwed into needle jet holder

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Needle jet holder by itself

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Needle jet holder (left) and main jet (right)

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The vacated hole where the needle jet holder was screwed in has the needle jet down in there. I carefully used the Craftsman pick and gently pushed the needle jet from inside the carb and it came out of that threaded hole. It has to come out that way.

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Needle jet (left), needle jet holder (middle) and main jet (right)

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Slow jet (stock #55)

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Slow jet (bottom) added to the previous group

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Step 33: Turn the pilot screw (also referred to as air/fuel screw) in and carefully count the number of turns until it seats lightly. Make a note of this to use as a reference when reinstalling the pilot screw.
** I have the SCain air/fuel screw made by SCain a long time ago. I will also show pictures of the stock screw and the "D" tool used to screw it in/out. What I did was use white-out to make a mark on the a/f screw, so I had a reference point when counting the number of turns. If you have the stock a/f screw, you can make a mark on the "D" tool that will accomplish the same thing.

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Step 34: Remove the pilot screw, spring, washer and )-ring. Check the pilot screw for wear and damage

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Here is the stock air/fuel screw, along with the "D" tool used to turn it. In the first picture, the flat side of the "D" shape is on the bottom of both the a/f screw and tool. The spring, washer and o-ring go on any available a/f screws in the same order.


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I also removed the following:

Idle adjustment knob (simply unscrews)

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Small filter from fuel inlet

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Carb vent tube that hangs off the left side of the carb (when viewed on the bike)

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Cotter pin, washer and accelerator pump link

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And here she is naked...and ready for a bath!!

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Hope I can get all this back together! :yikes:

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End of class!! :mrgreen::mrgreen:
 
#2 ·
Awesome pics and writeup. This definitely belongs on the step by step board.
Only thing I would add is put each assembly in a small baggie so all the parts stay together. It's a lot easier to deal with that way.

That accelerator pump looks bad!!:yikes:
How did the needle jet look?- they can get oblong.....may want to take a look at that if you need to order the accererator pump anyways.
 
#3 ·
Awesome pics and writeup.
Only thing I would add is put each assembly in a small baggie so all the parts stay together. It's a lot easier to deal with that way.

That accelerator pump looks bad!!:yikes:
Good idea on using baggies. If someone goes out into the garage and bumps that table, they'll be gettin' a butt-whoopin'! :shock:

That has to be from either water or condensation getting in there. I was shocked, too. I wonder if anyone else has seen this? I just checked hdlparts, and that part alone is $55.30!!! :yikes::yikes::yikes:
 
#5 ·
Beautiful write-up. Excellent Macro pics too. Well done. Needs to go to the "Garage Pages". :thumbup: :tools: :thumbup:

One thing I might mention. I have removed the carb entirely without draining the coolant from the bike. The carb is the high point so it will air-lock the fluid. This is especially handy if you are in a hurry or if you are removing the carb multiple times for dialing-in purposes.
 
#6 ·
Brilliant right-up that will save people hours of time and miles of message board questions!

Especially like how you compared the original needle with new one and pointed out differences that you know people are especialy intressted in. :thumbup:

What do you plan on cleaning the carb with?
 
#7 ·
Great write-up. If I ever get into it that deep the laptop will be beside me with this Thread on the screen. Great Job. Great Detail!! :thumbup:
 
#11 ·
Great writeup and pics. Please post to the maintenance step by step board so this doesn't get lost in the shuffle.
 
#13 ·
Wow I'm tired after just reading it
 
#15 ·
Superb!!!!:thumbup::thumbup: Thanks for the awesome write-up and pictures for all the lazy-a$$es such as myself that do not want to document a mechanical tear down and then wonder where a part goes when we put it back together. The Honda service manual doesn't even compare to this write-up. Again, thank you. :bowdown::bowdown:
 
#17 ·
Ill wait until i see it back together and running before i say "good job"
but one thing is for sure, you can tear stuff appart! :mrgreen::mrgreen::mrgreen:

why did you tear it down to begin with? other than it needs cleaned?
BTW, Ill be in CA. until tues. see ya when i get back.
 
#18 ·
Fantastic! :thumbup: :firstplace:

I've seen this happen on other message boards; with popular writeups like this Photobucket's servers don't like the heavy loads so the pictures stop working.

Just in case that happens, I threw this all together into a pdf. You can download it from here:

http://www.filesavr.com/mrvtxcarbclean

It's got one of those annoying "are you a human" questions, but I think you should be able to handle it :thumbup:


Thanks for posting this!! :tools:
 
#21 ·
Hey everyone,

Thanks for all the compliments, and I do hope this helps many people out. Now to answer some questions:

How did the needle jet look?- they can get oblong.....may want to take a look at that if you need to order the accererator pump anyways.
It looked okay to me, but I've got no reference to what a "good" one is supposed to look like. I may go ahead and order one (and maybe some more parts) too!

Very good write up but I have 1 question. What does the throttle position sensor do for a carbed engine. I understand what they do for a fuel injected but not a carbed.
I didn't know the answer to this, so I Googled it. I found this on WikiAnswers.com...it sounds good! :D

"The throttle position sensor (TPS) keeps the PCM informed about throttle position. The PCM uses this input to change spark timing and the fuel mixture as engine load changes. A problem here can cause a flat spot during acceleration (like a bad accelerator pump in a carburetor) as well as other drivability complaints."

One thing I might mention. I have removed the carb entirely without draining the coolant from the bike. The carb is the high point so it will air-lock the fluid. This is especially handy if you are in a hurry or if you are removing the carb multiple times for dialing-in purposes.
I had heard the same thing, too, but I was changing the coolant out at the same time. I will modify that step with a statement about not having to change the coolant, but having to burp the system to get air out.

What do you plan on cleaning the carb with?
I started cleaning it with paint thinner, but thought better of it since I wasn't too sure about using that type of solvent. I had a spray can of brake cleaner, so I got a bucket and sprayed the heck out of the entire carb. It worked pretty well. I think I may pick up a gallon container of Berryman's Chem-Drip Carburetor & Carburetor Parts Cleaner. AutoZone has it for $19.99, and it includes a tray so you can submerse the carb/parts in the container itself and let it soak. None of the rubber O-rings/diaphragms will go in...I'll just clean them with a mild solution of dish soap and water, and then oil them well so they won't dry out. The oil will be wiped off before they get reinstalled.

But, how many miles do you have on your bike?
A little over 62K.

Ill wait until i see it back together and running before i say "good job"
but one thing is for sure, you can tear stuff appart! :mrgreen::mrgreen::mrgreen:

why did you tear it down to begin with? other than it needs cleaned?
BTW, Ill be in CA. until tues. see ya when i get back.
Coming from an owner of a black VTX, I expected that! Well, to be honest, I tore it down because of two reasons.

1. For the last few months, when I would start the bike up and let it warm up before taking off, some black grit would come out of the exhaust...like little specks of black crud. I was thinking that it might be grit/crud that had built up in the carb. Hick mentioned that it might just be carbon build-up in the exhaust, so I'll clean that out, too.

2. I have been noticing a slight hesitation off the line sometimes when I gun it really hard. It doesn't happen all the time, but it drives me nuts when it happens. After reading what WiKiAnswers.com said about a bad accelerator pump (and looking at the pictures of mine), that might be what was causing this hesitation. Everything else was surprisingly clean, except the outside of the carb.

Fantastic! :thumbup: :firstplace:

I've seen this happen on other message boards; with popular writeups like this Photobucket's servers don't like the heavy loads so the pictures stop working.

Just in case that happens, I threw this all together into a pdf. You can download it from here:

http://www.filesavr.com/mrvtxcarbclean

It's got one of those annoying "are you a human" questions, but I think you should be able to handle it :thumbup:
Sweet! Thanks for doing this. As I modify the "class lesson" :mrgreen:, I'll let you know so you can upload the most current version. That's also why I have it in Word format, so I can e-mail it to anyone that needs it (and they can edit it to their needs). I can also convert it to a PDF if needed by others. I'm not really concerned about whether someone copies it and claims it as "their own".

to much work, buy an 1800:p
Try taking your fuel injectors apart for cleaning!! :p:p
 
#22 ·
I started cleaning it with paint thinner, but thought better of it since I wasn't too sure about using that type of solvent. I had a spray can of brake cleaner, so I got a bucket and sprayed the heck out of the entire carb. It worked pretty well. I think I may pick up a gallon container of Berryman's Chem-Drip Carburetor & Carburetor Parts Cleaner. AutoZone has it for $19.99, and it includes a tray so you can submerse the carb/parts in the container itself and let it soak. None of the rubber O-rings/diaphragms will go in...I'll just clean them with a mild solution of dish soap and water, and then oil them well so they won't dry out. The oil will be wiped off before they get reinstalled.
I had bought a used carb and broke it down as you did - I put it in a mixing bowl and cleaned it with carb cleaner (spray) and a parts brush. My wifes cookies tasted funny for a while though :grin:
For the rubber bits - silicone spray works well, and will also preserve it. Use a little silicone grease on the o-rings / gaskets (dielectric grease will be fine, go easy on it though)
 
#23 ·
Sweet! Thanks for doing this. As I modify the "class lesson" :mrgreen:, I'll let you know so you can upload the most current version. That's also why I have it in Word format, so I can e-mail it to anyone that needs it (and they can edit it to their needs). I can also convert it to a PDF if needed by others. I'm not really concerned about whether someone copies it and claims it as "their own".
Sure, i'd like to keep it up to date. I find PDFs easier for reading a finished project, since it's easier to zoom in and out without risking screwing something up :p

Plus I figure once you make any changes, I can add bookmarks with Acrobat Standard for stuff like "Disassembly" "Jets" etc etc
 
#24 ·
Sure, i'd like to keep it up to date. I find PDFs easier for reading a finished project, since it's easier to zoom in and out without risking screwing something up :p

Plus I figure once you make any changes, I can add bookmarks with Acrobat Standard for stuff like "Disassembly" "Jets" etc etc
Yeah, there are advantages to PDF over Word. 8)


Okay, I just finished editing the "lesson". I guess I impressed all of you so much that no one picked up on the fact that I said I was going to post pictures of the stock a/f screw and "D" tool...but I didn't.

So now, the statement has been added regarding not having to drain the coolant, and pictures of the stock a/f screw & "D" tool are there.

You will soon realize that I'm a perfectionist, so keep your editing fingers ready! :mrgreen: This thing will probably not even look the same after I'm done with it for good.

If I could get Hick or pepsX to come over in their high heels, skirts and bacon-thongs, I'm sure I could get them in the pictures somehow! They could pull a "Vanna White" while holding the parts! :yikes: :mrgreen: