Unbelievable Carbon Fouling!

Discussion in 'Whizzer Motorized Bicycles' started by Hal the Elder, Feb 23, 2009.

  1. Hal the Elder

    Hal the Elder Member


    This morning I removed Oscar's cylinder head to send to Quenton for milling.

    Now, I've owned 24 cars, 7 motorcycles, and one Whizzer, and I've had the engines apart on several of them, but I've NEVER seen such carbon fouling as on my new NE-5 with only 180 original miles on the odometer!

    As you can see, I've been running REALLY rich, and my 3000 ft. elevation doesn't help either! Carburetion changes are definitely in store for me!

    (What's that...SAND around the intake valve and on the piston head?)

    Now to begin scraping!


    Attached Files:

    Last edited: Feb 23, 2009

  2. RdKryton

    RdKryton Active Member

    Hi Hal
    You must have the #95 jet. Ask Quenton for a #82 or 85 when he ships back your head.


    PS That's not sand! It is serious carbon build up.
    Last edited: Feb 23, 2009
  3. Hal the Elder

    Hal the Elder Member

    Hey Jim:

    I just removed and opened my Carburetor. It has a #90 main jet.

    Quenton already said he would send me a #82.

    The black fouling seems to be firmly deposited on the piston and valve area...I thought it could be easily scraped off.

    Is there any chemical product that can dissolve the carbon buildup, or loosen it?

  4. 5-7HEAVEN

    5-7HEAVEN Guest

    Hal, I just removed my head; it looks EXACTLY like yours with carbon deposit.

    I'm at sea level with 1100 miles.

    I bought "Mr. Whizzard" last month and drove 50 miles to get the feel of it. At 40 miles I reamed out the carb's phenolic spacer.

    What a difference!

    :idea:Coincidentally, Hal, I'm copying every modification you're doing, even the WC-1 cam.

    :idea:Also need to use smaller jet.
  5. uncle_punk13

    uncle_punk13 Guest


    looks like all of the ones I've owned, and the couple I've worked on... LOL
  6. go-rebels

    go-rebels Member

    I would first use a steel wire brush mounted to a cordless drill. Then I would add a product like "Marvel's Mystery Oil", "Sea Foam" or Chevron "Techron" to the gas every time I filled it up. I had a major problem with carbon build-up on an old Cub Cadet tractor and "Marvel's Mystery Oil" does a good job removing carbon and continues to do a good job keeping it off. I've added that product for years in the gasoline used in all my small engines and have never had a problem with carbon.
  7. Hal the Elder

    Hal the Elder Member

    Hey 5-7 Heaven

    If you're going to copy every modification I make, then you'll install a WC-1 cam, run it for 10 miles, then remove it and re-install the stock NE cam!

    That's what I did, because the WC-1 reduced my overall performance, and re-installing my NE cam restored it.

  8. Hal the Elder

    Hal the Elder Member

    Hey Go-rebels:

    How about using my Dremel and a small rotary steel wire brush to get into the areas around the valves, with some kind of solvent (if any) to pre-soften the carbon?

    Last edited: Feb 24, 2009
  9. HoughMade

    HoughMade Guest

    I've seen fouling that bad..worse, but it was on a Briggs engine from 1967 that I rebuilt in 2006.

    And oh he!! no, don't use a standard (steel) wire brush anywhere near all that aluminum. Personally, I would not use a brass brush either unless nothing else worked, but that is probably OK. Remove it chemically with a nylon brush to start and give it time to work and let it soak from time to time- a mild solvent would be diesel fuel or mineral spirits- that's the place to start. Easy-Off oven cleaner will do the job, but I wouldn't want to use that unless I was completely disassembling the engine.
  10. Hal the Elder

    Hal the Elder Member

    Hey Hough-made:


    I'm glad you told me that before going in there with my Titanium Roto-Rooter!

    I'll try the Mineral Spirits (paint thinner) with a soft brush and keep at it until everything is perfectly clean.

  11. HoughMade

    HoughMade Guest

    Chipping the larger specks off with a tool is OK- and it is not so much the piston surface that I am concerned about (still would not use a steel wire brush on the piston), it is the cylinder deck.
  12. Mountainman

    Mountainman Active Member

    5 min of light scraping maybe ?

    Hi Hal

    you may just want to get the big stuff off as HM has recommended
    the old carbon buildup is just part of the engine -- comes in time
    yes - sometimes seems to be a short time

    when we rebuilt these small engines
    we didn't spend too much time knocking off the carbon
    5 min of light scraping -- should do it for now

    ride the motor bike
  13. august

    august Member

    A bead blaster with the glass beads. Five minutes, and no damage to the head.

    Just have to find someone with a bead blaster.

    Most every motorcycle shop has one, most won't charge for doing it, at least where I'm at.

    Regards August
  14. Hal the Elder

    Hal the Elder Member

    CAN't DO DAT!

    I've got to clean up Oscar's cylinder top right here in my garage!

    Wonder what Q would suggest...


    "The tail gun turret disintegrated as Bob's shells found their mark."
  15. WZ507

    WZ507 Member

    Carbon Removal


    Just get your brass "toothbrush" or any other substantial brass brush out and scrub away, being judicious to minimize stuff going down the bore (piston at TDC only).

    Little transgressions like this (running really fat) illustrate clearly why you want detergent oil in your engine. Without it, the rings would be well on their way to being glued in place. You can clearly see how the cooler side of the chamber prefentially loads with carbon, whereas the hot side has only minimal carbon buildup.
    Last edited by a moderator: Dec 15, 2015
  16. seanhan

    seanhan Member

    Man Talk about a Carbon footprint !!!!
  17. Hal the Elder

    Hal the Elder Member

    Hey Wz507:

    The Oil Guys on this forum all say to use STRAIGHT (non-detergent) SAE 40 in my ride.

  18. go-rebels

    go-rebels Member

    I've used a fine stell wire brush spinning very slowly on a drill with very light pressure. You don't want to apply any pressure that would create any heat. The scraping method will work fine too but can be time consuming. I wouldn't apply any solvent to soften the carbon first as that would only gum up the brush. Either use a wire brush at slow speed or use a solvent and scraper. A hand brass brush should work well too.

    I've shot glass bead but I would only do that to a head if I had it disassembled and in a blast booth. Shooting aluminum oxide, sand or glass bead in the open makes a big mess.

    And, of course, tape over the cylinder opening when doing any work.
  19. Hal the Elder

    Hal the Elder Member

    Hey Go-rebels:

    If I taped over the cylinder opening, I wouldn't be able to de-carbonize the Piston Head!

  20. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Hal & Oscar,

    Looks like you have several options to remove the carbon buildup. I have used, brass brush, carburetor cleaner, parts cleaner, scraped with a single edge razor blade, sand paper, oven cleaner, and too may other methods to mention. No matter which method you use, be sure to use air to remove any residue left between the piston & cylinder before re-assembly. And if you use any chemicals be sure to change oil to reduce chance of contamination.

    I will clean the carbon from your head before I return it to you.

    Have fun,