Page 1 of 4 123 ... LastLast
Results 1 to 20 of 68

Thread: Carb cleaning 101

  1. #1
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Carb cleaning 101

    Okay, this is something this site has needed for a long time. A couple of guys besides me were gonna do it, but I guess they got caught up with life (like me) and never got around to doing it. I'd bet gummed up carbs is by far the most popular problem bikes can have. They sit in the garage with old fuel in them for months and the gas gums them up. Cleaning carbs is super easy. I'm not the best at doing how-to's, so bear with me. When I'm done, feel free to point out something I've missed or something you'd like to add. Okay, here goes...
    I'm not mentioning removing the airbox or carbs. My bike is track only and stripped to the bone so pics of mine wouldn't do you any good. Grab a good manual and use it as a guide. First things first...use a quality carb. cleaner. In my opinion, B12 by Chemtool is BY FAR the best cleaner on the planet!! Start with a clean, dry place to work. A clean soft cloth is ideal for a work surface in case something falls (it won't bounce far on the cloth).
    "Crankenstein" is a GO...

  2. #2
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    The order I'm doing this is just how I do it. I'm just doing 1 carb here. You can disassemble all 4 carbs at once if you'd like (it's easier and faster). Just be sure and keep 1 carb's parts with that carb. The fuel mixture screws are the only exception, do them ONE AT A TIME! (I'll explain later). Start by removing the 3 screws holding the top cover on. Then remove cover, spring, and slide (be gentle with the slide)
    "Crankenstein" is a GO...

  3. #3
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    This next step normally isn't necessary, but I'm including it anyways. If you have OCD or something, you may want to do it. Remove 4 screws that hold stack to back of carb. Remove cover and stack, then remove O-ring type gasket. I'll explain why you may want to do this step in a few minutes.
    Last edited by cbr900racer77; May 26th, 2009 at 04:37 PM.
    "Crankenstein" is a GO...

  4. #4
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    To remove fuel screws, you need a special tool. If you don't want to pay a rediculous price for it or can't borrow one...here is how to get around it. Turn carbs over. Take a dremel tool with thin cutoff wheel and lightly cut a small channel across the head of the screw. Cut it just enough to be able to get a small flathead screwdriver in there and get screw out. Screw them in and count the turns and write it down. This way when you are installing them, you can get them back to where they were. After you get screw out, use a small pick with a hook on the end and dig out the spring. After the spring, there is a small metal washer. Then last there is a small rubber washer. Take your time here so you don't drop any of them, it's VERY easy to do. Do each screw one at a time. If you try all four the likelihood of dropping something is multiplied.
    "Crankenstein" is a GO...

  5. #5
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    Remove the 3 screws holding the bowl on and remove the bowl. Sometimes they are stuck and you need to lightly tap them with wooden screwdriver handle or something else that is fairly soft.
    "Crankenstein" is a GO...

  6. #6
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    Next, remove the pilot jet, main jet, emulsion tube (7mm wrench), and float/needle assembly (careful you don't drop the needle when lifting the float)
    "Crankenstein" is a GO...

  7. #7
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    Now it's time to do some cleaning. Cleaner is under alot of pressure and B12 will eat some eyeballs up so be careful using it. It will also get in open sores/cuts and burn like hell! Use an old toothbrush to clean inside bowl and a clean shoprag soaked in B12 to get in the corners. Anything that is a dull orange color needs to be cleaned. Using the red tube that came with cleaner, squirt some down hole in rear of carb. This is the air supply for pilot jet.
    "Crankenstein" is a GO...

  8. #8
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    Next squirt generous amounts of cleaner in holes for pilot jets and fuel screws. If you look at front of carb, there is a small port in front of butterflies. Cleaner should come out this port when spraying down pilot jet and fuel screw holes. If it doesn't, keep spraying it (alternating with compressed air) until it does. When a good stream is coming out the port, you know it's clean.
    "Crankenstein" is a GO...

  9. #9
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    Using the toothbrush and shoprag, clean rest of carb...throat, bowl, anything that has varnish on it. Clean emulsion tube with rag soaked in cleaner (make sure you can see through all the little holes on the sides) then install it (just snug tight). Next clean main jet and install. Then do pilot jet and install. Using rag, wipe off float (be gentle) and needle. Install needle in float and install. Then install bowl and tighten 3 screws.
    "Crankenstein" is a GO...

  10. #10
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    Supper time! will continue in a few....
    "Crankenstein" is a GO...

  11. #11
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    Next, install O-ring gasket at rear of carb. With it still in cover, install stack. It has 3 cutouts in it that go into slots in back of carb. While making sure Oring is in it's groove, install cover and tighten 4 screws. Take a rag and wipe off tip of needle.
    "Crankenstein" is a GO...

  12. #12
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    I've known several people that have trouble installing slides. Sometimes it's hard to get diaphram to seal, here's a trick. Push diaphram down over slide. Gently lower slide into carb body just enough to guide needle into it's hole. Next install spring into slide. Now lower top cover over the spring. Run your finger around the diaphram to make sure it's in it's groove in carb body. Run your other hand through back side of carb and using index finger, hold slide. Push down on the cover with one hand while slightly pushing up against slide with other finger. What you're trying to do is prevent slide from free-falling into carb. When cover is down on carb, hold it down with thumb of hand holding slide. Install the screws and tighten, then let slide fall. You've got it right if you can lift slide and it immediately free falls back down.
    "Crankenstein" is a GO...

  13. #13
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    Wipe tip of fuel screws with rag soaked in cleaner. Install spring onto screw, followed by metal washer, then rubber washer. Install screw into carb. Screw in until it lightly seats then back it off # of turns you wrote down when removing. That's pretty much it. They are ready to install. Make sure carbs are seated in boots and airbox is seated onto carbs. Bike will run like shit if either aren't seated properly. If you have any specific questions or need more pics, pm me on here or email me at hondaracer4u@yahoo.com.
    "Crankenstein" is a GO...

  14. #14
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    One thing I forgot...while you have float removed, get a Qtip soaked in cleaner and clean seat for the needle. A few good rotations should do it. Blow through fuel line with compressed air to make sure no cotton fibers are left in seat.
    "Crankenstein" is a GO...

  15. #15
    RRzone Member
    Join Date
    Feb 2006
    Location
    FL
    Posts
    69

    Bikes:
    93CBR-RR

    Default Re: Carb cleaning 101

    thanks CBR900Racer
    Very good write up. I think you are right about this being a common problem.
    I wish I had this info when I did mine.

  16. #16
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    yeah, it's easy to get in a slump and not ride your bike, especially if you've owned it for quite a while. Pilot jets are super tiny and clog easily. Carbs can be intimidating, but are quite easy once you get em tore down and get an understanding of how they work. You can use this for just about any carb, they are pretty much the same.
    "Crankenstein" is a GO...

  17. #17
    Meh. Derator. jawhn's Avatar
    Join Date
    Oct 2005
    Location
    xוuəoчd
    Posts
    7,450

    Bikes:
    98 Repsol Bodywork CBR900RR, 92 Plaid CBR600F2 Trackbike

    Default Re: Carb cleaning 101

    Just made this a sticky.

    Has anyone told you how awesome you are, yet? Let me be the first! Well done!!!
    __________________
    __________________
    .
    To add pics to your post: Use the "Manage Attachments" button below the "Submit" button

  18. #18
    Moderator gothy's Avatar
    Join Date
    Feb 2008
    Location
    Kent England
    Posts
    840

    Bikes:
    Honda CBR 1000 RR Fireblade ABS 2014

    Default Re: Carb cleaning 101

    Good write-up there m8.

    Im gonna be cleaning my carbs, when its dry one day this week. bloody uk weather
    Honda CBR900RR Fireblade, Suzuki SV1000s, Honda CB400 SF, Honda CBR600RR Hidden Content - GONE
    Honda CBR1000RR Fireblade ABS 2014 Hidden Content
    Forum moderator Hidden Content
    Valentino Rossi waving to me Hidden Content

  19. #19
    RRzone Elite a_morti's Avatar
    Join Date
    Jan 2009
    Location
    Portsmouth, England
    Posts
    283

    Bikes:
    CBR900 (96 RR-T / 918). XJ600S (97 Diversion / Seca 2)

    Default Re: Carb cleaning 101

    Brilliant writ up. Exactly how I did mine. For the needles, there are so many tiny channels, where my bike had been stood with fuel in it for two years, they were quite bad. I took all the removable needles and screws out, soaked them in a vodka bottle lid (metal, unlike coke bottles) of cleaner, blew them through with a spray duster can, and repeat as needed. Amazing how much green and white crap you can remove from such a small component.

    Be VERY careful with removable parts, they are brass and soft. Do not try to remove anything with an ill-fitting screwdriver (ask how I know).

    My fuel screws came out easy - are they different in the Dynojet stage 1 kit? As my bike has that fitted.

    Worth noting that it's a good idea to think about why your carbs are messy. Maybe it's obviously just time and build-up, or a long lay-up, but maybe your fuel filter gauze is ripped in the tank. I am not so impressed with the design of that. Cleaned the carbs three times before I thought to check it, so I'll mention it and maybe save someone heartache and irritation. You can fit an aux filter in the fuel line (just, it's tight) on later bikes with no pump, no idea on earlier bikes though.

  20. #20
    RRzone Elder cbr900racer77's Avatar
    Join Date
    Jan 2008
    Location
    middle tennessee
    Posts
    2,751

    Bikes:
    XX conversion is complete and kicking Busa butt

    Default Re: Carb cleaning 101

    EXCELLENT point a_morti! Forgot to mention taking it easy on the jets. They are soft and can easily be deformed with wrong size screwdriver. Don't try to clean them with a staple or paper clip, you'll scratch the hell outta them and could possibly change opening size. When you're tightening them, just a snug fit is enough. As for the fuel screws, the ones you get with jet kits already have slots for flathead screwdriver. It's just the stockers that are wierd. Do ya'll call em flathead screwdrivers in the UK? I have no idea what proper name is...slotted tip maybe?
    "Crankenstein" is a GO...

Page 1 of 4 123 ... LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

You can help to support this site by making a donation below
(even a small donation makes a big difference)
 
Make payments with PayPal - it's fast, free and secure!