The beauty of synthetic oil!

Discussion in '2-Stroke Engines' started by Steve Best, Jun 5, 2016.

  1. Steve Best

    Steve Best Active Member

    We are all used to pulling an engine apart and seeing thick buildups of carbon on the piston and head.
    Something like this:
    Even this is not as bad as we are used to. Note that is looks wet?
    This was semi synthetic oil and the deposit was actually a thick tarry goo that wiped off the polished parts.
    (note also a slight head gasket leak)
    Here is what it looked like after wiping off:
    I might have been able to clean the cast section better if I had used more elbow grease.
    We are all used to the thick hard carbon build up from conventional oil, that can only be scraped off.

    I put this head back on exactly as photographed and continued testing spark plugs on long trips.
    Instead of semi-synthetic, I switched to Motul 800 full synthetic.
    At about 70 kms (with about 500ml of semi synthetic mix fuel left in the tank) looks like this on the left:
    On the right is an aftermarket head with much of a tank of fuel (about 80 kms) on it.
    These deposits wiped off to clean metal with a paper towel.

    Notice signs of the factory head leaking at the head gasket again. It runs at faster speeds 60-66 kph (9500rpm) whereas the head on the right runs 55-58 kph (8000rpm) with no detonation.
    The head on the right has huge torque at very low speeds and keeps speeds on the hills better.
    The head on the left's tendency to detonate at speed is probably what is stressing the headgasket, as well as being weak in the fore/aft plane. The head on the right has no tendency to detonate and keeps rpm under 9000rpm, very good things for longevity.

    This is not the first time I have seen this. Here are pictures from my KTM 125:
    Left is 7 years of Ipone and Motul full synthetic and rich fuel jetting.
    Center is from a used motocross KTM 125 bike I bought, conventional oil, rich jetting.
    Right is several years and thousands of street and trail kms (note the headgasket) with Ipone and Motul full synthetic and lean jetting.

    Last edited: Jun 5, 2016

  2. I F#€£D UP BIG TIME! BUT? I immediately stopped! And pulled in clutch turned around and went right back in my garage straight up the driveway. Late last night very very very very tired I put in a plug it was a bit longer than the other plugs I have been using. But I thought hey it's honestly if it had they don't have enough clearance and I'll just 'ROLL IT' in the morning to make sure it's not hitting ER anything. SO,,,,,,, I immediately pulled the plug and it was crushed, Porcelain was cracked in pieces, It looks like I got him a lot when I reconstructed the porcelain and I noticed a little tiny piece was missing.
    Time to pull the head off. This is what I found now I don't know if they painted the inside of the head I don't think so I think this needs to be clean because the top of the Piston is the same color I believe its carbon buildup. The good thing is there are no leaks on the head the only oil at the top of the head around the gasket is from the muffler, Search Tilt the black Gunk inside the head and on top of the Piston I honestly think it was painted and I think it's carbon buildup on top of tank only time will tell as I clean it I will keep you updated thank you any input is very much appreciated thank you in advance.
  3. Frankfort MB's

    Frankfort MB's Well-Known Member

    Had that happen before... Not fun playing hide and seek with peices of porcelain and metal :)
  4. The hug barely move or the tub sorry the Piston barely moved so it's not that bad I just have to clean it up a little bit but what I'm concerned about is the color in the carbon inside, I hope you're not offended but I can't figure out how to post a God damn picture and I'm here!!!!!!
  5. It doesn't give me a choice to choose from my gallery on my phone and my camera anything it just pulled up all these ridiculous options that I can't use any picture from
  6. Oh well got to get to work Gotta clean this up and put it back together for the regular spark plug in
  7. Frankfort MB's

    Frankfort MB's Well-Known Member

    if your having clearance issues you could try a champion RJ19LM
    It's off an old stihl chainsaw but works pretty good on my bike, I had to use a different plug because of my head (the stock plug was the only thing I could find that would work because the b6hs was too long)
  8. Nanonevol

    Nanonevol Member

    I think you need to upload your photo to Photobucket or someplace like that on the web, then copy it there into this forum. It's a bit of a PITA
    WINDY CITY BOB likes this.
  10. Oh no I have plenty of clothes I've got NGK plugs E3 plugs They all work I just had to take it a step further like an idiot
  11. Typo plugs. Not CLOTHES LMAO!
  12. As long as I got you're attention what grit papaer would you use to smooth your head, 320, 220, er 400?
  13. Frankfort MB's

    Frankfort MB's Well-Known Member

    I use whatever I have, most the time it's 220 but it's better to use higher grit
  14. Those ate the 3 I have. You would use 400?
  15. Frankfort MB's

    Frankfort MB's Well-Known Member

    It would get it smoother so better sealing but any reasonable grit works fine (nothing less than 200 grit) 60 grit would leave gouges
  16. I used 400 , it's shinin like a diamond in a pigs ass! I tell yah man, after I cleaned it l? HOLY CRAP! What was once black, is now looking like chrome.
    And I SWEAR they painted the inside of the head and the top of the piston. Or, i had some major carbon build up the same color as the engine.I've got pictures but ill post a bunch of stuff when I figure that out. Gotta be simple like you said.
    Island Racer likes this.
  17. Island Racer

    Island Racer Member

    There's a button on your screen UNDER where you type and it says

    Post Reply... Upload a File.. More options

    Push the button: Upload a File ... try it ?
    Then choose file & documents...