2 questions

Discussion in 'General Questions' started by Rockjaw, May 30, 2014.

  1. Rockjaw

    Rockjaw Member

    Hey all

    1) how much fuel does the factory ( basic chinese kit)gas tank hold? is it 1/4 of a gallon?

    2) can the engine run if i remove the head ? or do I need to replace the metal head gasket

  2. butre

    butre Well-Known Member

    The engine can't run without a head, no. If you mean without a head gasket, then yes it can run but it won't necessarily run well unless you've planed the jug and head perfectly smooth, in which case it would still probably run better with the gasket. I ran mine without a head gasket after absent mindedly forgetting to put it back on when I had finally decided to loctite my head studs in place and compression (and power) was way low so I immediately pulled over and inspected it. My head and jug are both planed all the way up to 1000 grit and I'm still better off with a gasket. Unless you've planed to at least 1000 grit and then mated with valve grinding paste I wouldn't try it.

    You can reuse the old gasket, you don't need to replace it with a new one.

    I think the factory tank holds 1.5 liters, but don't quote me on that. I know that I can fill it from empty with a little under half a gallon.
  3. Rockjaw

    Rockjaw Member

    ok great
    yeah i mean run without replacing a head gasket after opening the head once..

    .the engine isnt running..i was getting no spark and the magneto was bad..just replaced that and now i have spark..still not running..i loosened the exuahst bolts ..so i dont believe its the muffler..when i try to start it ..it sounds like its pushing air out ..not sure what happened...maybe piston is bad
  4. Fabian

    Fabian Well-Known Member

    Honestly, wouldn't it be a heck of a lot easier to just get out the credit card and order a CR Machine Manufacturing billet cylinder head that does the job properly; and doesn't leak, and is of superior design and delivers far greater cooling efficiency, as well as producing improved power.

    Grinding, pasting, honing, gritting, mating, and you still have a poor quality cylinder head at the end of it - ahh to heck with all of that rubbish. Just get yourself a proper billet cylinder head (bolt the thing in place) and be done with wasting precious time.
  5. butre

    butre Well-Known Member

    The jug is a bigger concern than the head. The stock heads are milled fairly flat and the problem is more that they tend to warp. The jugs as far as I can tell are just cast and never milled.

    Besides that, it cost me $4 worth of sandpaper and half an hour instead of $90.

    I don't have any problems with overheating either. I don't know why you do. Maybe the humidity or the atmospheric pressure in our respective locations is affecting it somehow.
    Last edited: May 31, 2014
  6. butre

    butre Well-Known Member

    It's not getting air, fuel, spark or compression. That's all an engine needs to run.
  7. crassius

    crassius Well-Known Member

    clean the engine well, then pedal the motor a while and look carefully for seeping oil - if it's leaking somewhere the oil will show up there
  8. Rockjaw

    Rockjaw Member

    ok thanks! ..it just has a sound like bicycle pump when i try to start it..pushing air
  9. Fabian

    Fabian Well-Known Member

    and at the end of it you still have a sub standard cylinder head when a far better option is available off the shelf. It's most foolish not to exploit that option.

    Because i use my bike as a transportation tool and not as a toy. It must operate under incredibly arduous conditions as well as cruising along to the corner store.
  10. butre

    butre Well-Known Member

    I think the source of your overheating problem is that you seem spend a lot of your time in low gears at low speeds with heavy loads. Mine is transportation too, but mine is carrying a third the weight yours is. I could see an aftermarket cylinder head being beneficial in your situation, but in mine it simply wouldn't do me any good unless I was wanting to boost compression.
  11. Fabian

    Fabian Well-Known Member

    The standard cylinder head does not have a squish band which is just one reason why it's a poor choice when compared to the available aftermarket cylinder heads that are machined with a correctly designed combustion chamber, with a choice of compression ratios.

    No amount of grinding, pasting, honing, gritting and mating will fix a poorly designed combustion chamber, and at the end of the day a well designed billet cylinder head is a "one-time" investment. After 6 months you won't even remember spending that $90
  12. Fabian

    Fabian Well-Known Member

    I have to completely agree with your comment, which is why i need to seek out the best available aftermarket options for my motorized bicycle.
    I don't have a choice with respect to using substandard parts/components on my bike, because i need bullet proof reliability and functionality.