Breaking Down a China HT Engine in PICTURES

Discussion in '2-Stroke Engines' started by Al.Fisherman, Oct 9, 2009.

  1. Al.Fisherman

    Al.Fisherman Active Member

    Here in Alabama, we have probably the most relaxed laws in any state concerning MB' is spelled out, nothing ambiguous, no interpretation, just ride. The chances of getting pulled over is nill. However my son has been pulled over twice, riding home from work at 3AM, however I don't agree, but understand. It was 3:00 in the morning, should something been going on the officer has a suspect..Like I said I don't agree, if he wasn't doing ANYTHING wrong, he had absolutely NO reason to be stopped. If it happened one more time I was going to lower heaven on the police department in this small town. We live in a free state, and those were really unwarranted stops. Then we have the police that just want to look at them...had never seen one here till we built out two builds.

    !. 150cc or less
    2. NO tag needed
    3. NO title needed
    4. NO registration needed
    5. NO insurance needed
    6. NO license needed
    7. Must be at least 15 years old
    8. Follow the rules of the road
    9. Lights, front and rear if riding at night
    10. And wear a helmet.

  2. joeltrain

    joeltrain New Member

    crankshaft replacement

    After discovering my 2009 gt5 crankshaft will not fit in my 2010, I reinstalled it. The 2009 has main bearings pressed into case. The 2010 has bearings pressed onto crank. Here's what I did:

    1. Push small gear side of crank through rubber bearing protector. See pic crank1_104_1533.

    2. Place 16mm short socket on chain gear, LEVEL cases to each other and GENTLY hammer socket to get bearing started on clutch shaft. See pic crank2_104-1534. Once both sides of case are close enough together I started the 3 flat head machine screws near the clutch shaft, the two flat head machine screws at the front mount and the 1 machine screw at the bottom of the case. I tightened them in a counter clockwise fashion starting at the lower front mount location. DO NOT tighten any one screw too much at once. You are trying to slowly work the two sides of the case together. See pic crank3_104_1535. Once you have both sides of the case pretty close together start the two phil/flat machine screws at the top of the case. I saved these for last b/c they tend to strip out at the head.

    3. Turn case over and install woodruff key into small gear shaft. Use appropriate socket, line up slot in gear and GENTLY hammer into place. See pic crank4-104-1539. Place star lockwasher into place and install large flathead machine screw. See pic crank5_104_10544. Install nut on magneto side and tighten all the way down. 14mm o/e wrench on magneto side and tighten large flathead machine screw all the way down. See pic crank6_104_10545.

    4. Repeat step 3 on clutch plate. To tighten down nut, jam nut the other side of shaft.

    5. Turn case over again. Install chain gear using same method as above. See pic crank7_104_10546 and crank8_104_10547. To tighten nut this time you can jam clutch plate and small gear using a screwdriver.

    6. Flip case over again. Install clutch spring, and push pressure plate onto shaft. Use needle nose pliers to tighten star nut a little past snug. Keep pressure plate from turning by running your chain around the gear on the other sdie 2x to jam it. Install small screw that keeps pressure plate from loosening.

    7. Now the fun part. Flip case one more time. Install backing plate using magneto screws with nuts to compensate for overlength. See pic# crank9_104_1552 . Install woodruff key. Pull connecting rod all the way up. Keyway s/b at 1 oclock. Install magneto as seen in this pic crank11_104_1557. Make sure magneto is in this position with shaft all the way up or your timing will be wrong! I found it helpful to use a flat screwdriver to keep key from falling out of slot while i gently hammered magneto onto shaft. See pic crank10_104_1556. I used a socket to hammer into place once I was sure magneto was going to go on key straight.

    Hope this helps somebody!

    Attached Files:

  3. Big Red

    Big Red Active Member

    California Legal

    Hey gera, I live in San Jose, Ca. and have been riding M.B's for about 5 years now. I have been checking out Ca. law for almost that long also.
    DMV sec. 406 describes what a M.B. is.
    DMV sec.5030 says SPECIAL PLATE required.
    DMV sec. 12804.9 M-2 license required.
    Helmet required and also lights at night.
    With all that said, I have never been asked to show an M-2 license. I have never been asked to show proof of reg. on my M.B. Cops mostly think it's just too petty to mess with. BUT, There's always a chance of getting pulled over by THAT cop. Just be VERY polite to the officer and you should be OK. Pleading ignorance generally gets you off the first time with the A- hole cop. I had a Sargent from S.J.P.D. tell me I needed a license and reg. for it.(no ticket.) That was last year and have'nt had any problems since. Study the law for yourself and decide if you want to be a rebel or law abiding citizen. I'M A REBEL and will be untill the day I die. (or get my first ticket.)
    Big Red.
    Last edited: Sep 19, 2011
  4. remichi

    remichi New Member

    This is a very helpful post with clear pictures! Thanks. Hopefully it will help me understand the engine better and get it finally running. As explained in my other post I have not got my engine running yet and have the problem that the engine is permanently disengaged. If anyone has any solutions to my problem, al thoughts are welcome!
  5. V 35

    V 35 Member

    I appreciated the slide show, learned a lot, love the logical order, and the use of ' other ' engine shots to simplify things.

    The best tip ... 8 case screws, two under clutch that will save some cases from getting busted up during teardown.

    One ' minor ' improvement I'd suggest ... A photo of the tools needed . Thank you for sharing that confidence builder,
    now we've got less excuses for busted motors.
  6. Big Red

    Big Red Active Member

    Three screws under the clutch, No big deal though. If you get far enough to see two of the screws you'll see the third.
    Big Red.
  7. ajm

    ajm New Member

    My bike wont start trouble shot all the way to towing it still nothing let sit still nohing. I think my headgasket blew need info
  8. crassius

    crassius Well-Known Member

    look for signs of oil leaking around head gasket & case seams - if clean, check the crank seals
  9. Pablo

    Pablo Motored Bikes Sponsor

    It won't start without compression.

    Got spark?
  10. V 35

    V 35 Member

    Head gasket troubleshooting

    Pour a small amount [ teaspoon full ] clean engine oil [ 4 cycle engine oil, car oil ] down spark plug hole, with plug out release clutch, and ' roll ' motor by pushing . After hearing what sounds like corn popping [ compression ] Replace plug, and try motor, a bad gasket will blow oil until it seals, if it ever does ? An oily film will form around marginal gaskets. If all is tight, pull mag cover, check seal, clutch side seal is harder to access, but you should spot the oil drip. Hope that helps
  11. KCvale

    KCvale Motorized Bicycle Vendor

    Here is a new video U-tube animation video of exploding, then re-assembling a typical 2-stroke China 66cc engine.

    Just turn your sound off unless you are a Rocky fan hehe ;-}
    Last edited by a moderator: Dec 15, 2015
  12. Fly1

    Fly1 Member

    That's slick! That should help even a person that never opened a engine before. Some one did a nice job.

  13. KCvale

    KCvale Motorized Bicycle Vendor

    Ya, I got a couple of bare engine kits gasbike had, one for spare parts, and one I assembled.
    The video leaves out a couple of really important parts like seals and keyways but overall a really fine job.