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Removing carbon

Discussion in 'The Garage' started by 59Tebo, Nov 6, 2018.

  1. 59Tebo

    59Tebo 59Tebo Top Contributor

    After reading everything I could find (which, to my surprise was not that much), I'm still somewhat in the dark as to how to remove the carbon from the valves, combustion chamber, piston domes, etc. I gave the pistons a soak in a 50/50 of kerosene and brake fluid, then scrubbed with bronze wool and a bronze brush. They came out clean-er-ish. :umm: When I did the same with the valves, the solution barely touched them. :doh:
    (I didn't even try doing anything with the combustion chambers) Could this be the difference between the aluminum in the pistons, and the valves being steel? Should I just say " :wtf:" and spring for new, stainless steel valves? I've also heard of using oven cleaner and ammonia (not at the same time! :eek: ). So, keeping it simple, cheap (important, 'cause that's me!), and efficient, how do I get that damned carbon out of there?! And how clean does everything have to be (during a top-end rebuild) for me to get the most out of my efforts? I understand where I'm at now is going to be better than where it was the last time it ran (20+ years ago! :yikes:), but does anyone have any other ideas/techniques? Am I just being impatient? Do I need to leave the valves in "the dip" for days/weeks for the carbon to soften enough to remove? Thanks in advance for your help...
  2. willis

    willis xsive compulsive disorder XS650.com Supporter Top Contributor

    paint stripper. 5twins recommended this and it worked beautifully for me. I used a gel style and took a couple of applications but turned out great.

    IMG_0531.JPG IMG_0538 - Copy - Copy - Copy.JPG
    IMG_0532.JPG IMG_0563.JPG
    Camilo, Wulfbyte and 59Tebo like this.
  3. 5twins

    5twins XS650 Guru Top Contributor

    Yes, paint stripper. It also works well for removing the old stuck on gaskets. As mentioned, several applications will be required. You can help it along by scrubbing with an old toothbrush after it's soaked for 10 or 15 minutes. I finish up with chrome cleaner. That will remove most of the staining and discoloration left by the carbon. Thread strips of oiled up rags through the valve guides to protect them. Any small bits of carbon remaining after the stripper soaking are usually easily scraped off because they have been softened. Last step is a good scrubbing with hot, soapy water to removes any stripper remnants and chrome polish residue. The oiled rag strips in the guides get replaced with fresh ones because the washing has no doubt gotten them wet.

    The paint stripper won't do much on the valves because that carbon is really baked on, especially on the exhaust valve. But, the valves are hardened steel so you can safely wire wheel them clean.
    59Tebo likes this.
  4. weaselbeak

    weaselbeak XS650 Junkie

    When rebuilding old cars back in the 60's we just tossed the carboned up stuff in a bucket of water overnight. Water dissolves carbon.
    gggGary likes this.
  5. aldo5468

    aldo5468 Redleg XS650.com Supporter

    Just be mindful of the ingredients, use with plenty ventilation - "classic" strippers usually loaded with methylene chloride, which is not kind to the human organism. Dry cleaners had to eliminate it many years ago.
    Wulfbyte likes this.
  6. fredintoon

    fredintoon Fred Hill, S'toon. Top Contributor

    Hi Tebo,
    Chuck the valve stem in a drill press set to a high speed and hold a strip of emery tape to it.
    Never mind the seal area, it gets lapped into the head on reassembly.
    Loose pistons:-
    Clean up the crowns with a scraper then shine them up on a polishing wheel.
    Pistons still in their bores and cylinder heads:-
    Gotta scrape 'em by hand, I use the curved end of a hacksaw blade with a squirt of kerosene.
    59Tebo likes this.
  7. 59Tebo

    59Tebo 59Tebo Top Contributor

    Awright, guys! These all sound good! Now that I know the valves are "hard", I will use more aggressive methods to clean them. The whole top end is off, and apart, so I'll do all of the above. I don't have a polishing wheel, but I do have a Dremel...
    Oh, and not to change the subject :offtopic::hijack: , but what do you think if I replaced all the washers with copper washers?
    Jim likes this.
  8. 5twins

    5twins XS650 Guru Top Contributor

    You mean the ones on top under the 8 big acorn nuts? It's an unnecessary expense really. Only the outer 4 need replacing with the copper (or brass). The 4 inner studs are dry so don't require a sealing washer.
    Jim likes this.
  9. 59Tebo

    59Tebo 59Tebo Top Contributor

    Understood, 5T, but they look cool... :laugh: And, I'm thinking about all the washers (for the sake of uniformity. And they look cool... Did I say that already?)
    gggGary and Jim like this.
  10. Jim

    Jim Beyond the edge, is the unknown. Here be Dragons XS650.com Supporter Top Contributor

    95 cents each at Ace hardware. For an extra 4 bucks..... go ahead... do 'em all.:D
    gggGary likes this.
  11. fredintoon

    fredintoon Fred Hill, S'toon. Top Contributor

    Hi Tebo,
    Yamaha's sealing washers are plain steel with a layer of rubber bonded to one face.
    Which means the more you tighten the head nuts the more the rubber squeezes out so they can never seal properly.
    Yes, plain copper or aluminum washers work kinda OK but Dowty washers work perfectly.
    They are plain steel washers with a rubber seal bonded to their inner diameter so that they let the head nut be fully torqued down
    onto a steel washer while the seal in it's bore gets tightened onto the head studs to prevent oil leaks.
    Drummond-McCall sells them by the ten-pack.
    59Tebo and Wulfbyte like this.
  12. Camilo

    Camilo XS650 Member

    I'm having the exact same problem! Thank you for your suggestion and photos willis, will give it a go and see how it goes!

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