Is it worth fixing??

Discussion in 'General Questions' started by Tyler6357, Mar 11, 2012.

  1. Tyler6357

    Tyler6357 Member

    Hello everyone, I'm still very new here. Here is my situation. I decided to put a motor on my old mountain bike a few months ago. Unfortunately, I got a cheap 66cc/80cc 2 stroke China special. It was the only 2 stroke engine I could find that would ship to CA. I have driven it only 500 miles and today while I was coming home it totally lost power and started backfiring. I adjusted the idle screw to get it to stop backfiring but it just has lost its power, I limped it home at about 11mph. I figured it was a fuel problem so I took apart the carb but everything looked to be working fine. I then thought the problem could be that the muffler might be starving it because I could hear loose parts inside so I took apart the muffler and tightened the screws that had become loose. However when I took the muffler apart I found several small medal balls that look like ball bearings. I think these must have gone through the cylinder and out the exaust and got stuck in the pipe. I haven't taken the head screws off the motor yet. I haven't looked at the cylinder or anything yet. Have I blown something inside the engine? Is it at all worth trying to fix? Keep in mind that I got the entire kit, with the engine, for only $165 shipping included. I'm not a mechanic! Is it pretty easy to replace these ball bearings? Can I purchase these bearings and replace them myself for cheap or is it not worth it?
    Thanks to all who respond!
    Ride-on
     

  2. Al.Fisherman

    Al.Fisherman Active Member

    First of all are they actually "BALL" bearings, meaning that they are round? Or do they look like broken needle bearings? The only place you will find a ball bearing is from the 2 crankshaft bearings, and if so the engine has to be split to replace them. Here is a picture tutorial of taking the engine down.
    http://s982.photobucket.com/albums/ae309/Ron-Becker/Chinese HT breakdown/
     
    sixbysix76 likes this.
  3. Tyler6357

    Tyler6357 Member

    Thank you for your help. I am definitely going into the engine just to inspect for damage and to see if it is salvageable. If I can replace whatever is broken and if the cylinder is still ok after having pieces of medal run through it I will try to fix it myself I guess. I will purchase replacement parts from your store if I decide to try to fix it.
     
  4. Prolly a head gasket.

    Usually when something like that happens I feel like GOD is telling me to tear her down completely have a look and put er back together, it usually works.
     
  5. motorpsycho

    motorpsycho Active Member

    are you positive that they are ball bearings?
    if they are ball bearings from the crankshaft, the engine shoudl have locked up.
    besides that they more than likely would have fallen down into the lower part of the engine. For them to make it into the muffler, they would have had to find their way onto the top of the piston (which would have locked the engine up), and then out to the exhaust. since the piston is solid (doesn;t have any holes in it), i see no way for bearings from the crankshaft to make it on top of the piston. if ball bearings were on top of the piston, they would have been between the top of the piston and the combustion chamber and the piston never would have made it's full stroke....it would have just locked up.
    what i think you have is welding slag from the cheap welds when they weld the muffler together.
    if what you have are ball bearings, i'd be curious as to how they actually made it out of the engine without locking it up.
    post a pic, of these bearings so we can see exactly what you have.
    This is just my opinion, and I could be totally wrong, but i really don't see how ball bearings from the crankshaft could have made it into the muffler.
     
  6. Al.Fisherman

    Al.Fisherman Active Member

    motorpsycho...I'm with you on this. If it is actually a "ball" bearing, he's got to be one lucky guy, for the engine to not to lock up and destroying anything....oh so many things could of gone wrong. I doubt that it's a bearing to begin with. Strange things can happen.
     
  7. Tyler6357

    Tyler6357 Member

    Update

    Hi guys!
    First: I took some pictures of the small balls and pieces of metal that I found in the exhaust pipe. I took some pictures next to a tape measure so you could see how big they are (see pictures 2251-2253). Anyone know what they are from??

    Second: I took the engine off my bike and took the head screws off to check for damage to the piston and the cylinder. I noticed some nicks in the piston from when the medal pieces went through the engine. There are 2 on one side (see pictures 2254-2258) and 1 on the other (see pictures 2261 and 2262). You can see scratches down the side of the piston too (see pictures 2254-2258). Does this piston looked too damaged to use or are those scratches and nicks no big deal? The cylinder itself looks pretty clean with no scratches on the inside (see pic 2259).

    The piston seems very loose. I can turn it about 25 degrees or so. I took a picture of it (see picture 2255), then turned it as far as I could and took another pic (see picture 2256). Also, the up and down has a lot of play in it too. Is this normal or is there something wrong? Also, I don't see any piston rings, shouldn't there be rings around the piston or am I wrong?

    I haven't taken the rest of the motor apart yet but before I do I was hoping someone could give me an idea of what I might be dealing with and what could have happened. Any recommendations on what I should do next? I'm not really a mechanic and I'm a total rookie taking engines apart.

    Thanks
     

    Attached Files:

  8. motorpsycho

    motorpsycho Active Member

    well, your piston rings are there (they are the 2 rings in the slots cut into the piston).
    by the looks of that piston, i would have to say that something definitly went past the piston to cause those grooves in the sides. But, you say that the cylinder bore is not scratched?
    hmmm, those peices don't look like bearings to me tho. they look more like peices of broken piston ring in a way.
    the piston is trashed in my opinion.
    i still don't see how peices of anything made it past the piston and out the exhaust tho, unless the rings are broken and that's what those peices are.

    was the cylinder really easy to slide off of the piston?
    if the rings are right, you should have had some resistance when sliding the cylinder off of the piston, because the rings are what ride on the sides of the cylinder, not the piston.
    the piston doesn't actually touch the bore of the cylinder, just the rings do. by the looks of your rings tho, i'd say that there's no way that they could be touching the cylinder bore all the way around. they appear to be sticking out of the grooves only a little bit and only on one side. the rings should be sticking out from the piston all the way around. when you slide the piston back into the cylinder you should have to compress the rings slightly to get them into the cylinder bore.
    look closely at the rings and see if there are any missing peices.
    If i am correct, there should be pins in the piston ring grooves to keep the rings from rotating, but i've never had one of these apart that far.
    I think either you broke the rings, or the ring pins came out, but that's an aweful lot of metal for it to be the ring pins.
    I'm guessing broken rings...but you never know, that stuff could actually be from the crank shaft bearings.
    since i've never had one this far apart before, i'm just guessing.
    I'm really surprised that it ran after this happened because by the looks of the rings, it probably had very little compression.
    thinking more about it, i think if it was the crankshaft bearings, it would have eventually locked up.
     
    Last edited: Mar 12, 2012
  9. Porkchop

    Porkchop Member

    Yes, strange things do happen. Looks like the bearings found their way up between the cylinder wall and the piston and out through the exhaust pipe. Looks like someone is in need of a new engine. As cheap as these things are, I wouldn't try to rebuild it. I'd just throw it away and buy a new one !
     
  10. Tyler6357

    Tyler6357 Member

    Update2

    Okay, I can see the rings, I just had to wipe the grease away, haha. The rings each have one break in each of them. I'm not sure if that is by design (so you can get them on?) or if they are broken. I suspect that they are broken. They don't rotate on the piston but I can make them flex out slightly around the breaks. I don't see any pins but it's possible my eyes just can't see them but I don't feel any. Also, the cylinder did have some resistance when I slid it off the piston, not alot, but it didn't just slide off. I took some pictures of the breaks in the rings the top one (see pic 2064) and the bottom one (see pic 2065). However, I agree that there was too much medal in the exhaust pipe to simply be only the pins. The pieces of medal look like round balls. Some of them got crushed going through the piston but one of them looks like it is hardly banged up at all and it is a perfect ball like a small ball bearing (see the one on the right in picture 2253 above). I should say that I had to zoom in with my camera to get the pictures of the nicks and scratches on the piston above, they are actually very small (less than 2 mm wide) and less than (1 mm deep). The largest one (picture 2262) is about 2mm wide and at just over 1mm deep. They might look larger in the pictures than they actually are. Also, the cylinder surprisingly has no scratches for grooves, it only has one very slight nick that is so small I can barely feel with my finger. How this can be I don't know.
     

    Attached Files:

  11. Porkchop

    Porkchop Member

    The “break” you’re referring to in the rings is called the “gap”. If the rings were solid with no gap, you would not be able to spread them to get them onto the piston. As far as previous remarks about the rings sticking out further on one side of the piston and not symmetrical all the way around is normal. The rings will move from side to side, so to say, until they are inserted into the cylinder. Once inserted down into the cylinder, the cylinder actually keeps them compressed so they fit tightly against the piston all the way around. And yes, the piston holds the rings in pace inside the cylinder, not the other way around. That and to provide compression. When the rings are on the piston and all is inserted inside the cylinder, there is still a minute gap between the ends of the rings. The ring gap is so small, all the compression will not travel through them as the piston is going up and down is so fast. The pins in the side of the piston is to keep the rings from rotating around on the piston and lining up with each other. If they were to line up with each other then you most likely would experience a considerable loss of compression. Most automobile engines I’ve ever fooled with have three rings. The gaps are equally spaced from one another. In a three ring application that would be 120° from each other. In a four ring application it would be 90° from each other.
     
    Last edited by a moderator: Dec 18, 2015
  12. motorpsycho

    motorpsycho Active Member

    yes, i forgot to mention that the rings will "float" inside of their slots in the piston.
    they should not rotate tho, and that's what the pins are for.
    porkchop is 100% correct.
    To me, it doesn;t look like the rings are broken and the pins appear to be there.
    so, what are thos peices of "bearing"??
    i find it hard to beleive, but they just may be crank bearings as suspected.
    something obviously went through the cylinder between the piston and the bore.
    the only way to really find out if it is crank bearings is to split the case and have a look.
    if it were me, i'd just buy a new engine (not a complete kit, but just the engine) but i have no idea what your $$ situation is.
     
  13. Porkchop

    Porkchop Member

    I haven't priced Crappy Time bare bones engines lately, but obviously the piston & rings need to be replaced. Probably has serious cylinder damage along with what appears to be crank and/or rod bearings which might incur a need for a new rod and crank shaft along with rod and/or crank bearings as well. As previously said, you’ll never know unless you take the whole engine apart. I have not taken one all the way down in years. I don’t remember all the details, but it was pretty simple and easy to put back together. Of course with this engine, what have you got to loose. I think it would be cheaper and less hassle to rebuild this one even if it is rebuildable. If and when you do take the engine all the way down, please post photos and keep us posted Just my $.02 !!!
     
  14. motorpsycho

    motorpsycho Active Member

    not the best vendor according to some (i've had good luck with them) but the price is right in my opinion. a lot less hassle than re-building, and making sure that it's right when done.
    http://www.ebay.com/itm/Motorized-B...436?pt=LH_DefaultDomain_0&hash=item27bd9552d4

    here's another one, but I'm unfamiliar with this vendor.
    http://www.ebay.com/itm/BRAND-NEW-6...035?pt=LH_DefaultDomain_0&hash=item35b867efd3

    you can get a new cylinder, new piston and new rings from bgf too.
    but, the price is about 1/2 of what a complete new engine is. then of corse if you old engine has crankshaft, connecting rod and bearing damage, you'd probably have the same amount of money invested to re-build than to just buy a whole new engine. you'd have to get all new gaskets, bearings, possibly a connecting rod and possibly a crankshaft, plus the hassle of doing the work. I know, it can be a learning experience and it isn't a bad idea to re-build to learn. but, if time is a concern, then a whole new engine is the way i'd go. but if you've never re-built one, and you end up doing something wrong, your money spent on parts is down the drain.
    http://www.ebay.com/itm/Motorized-B...Cycling_Parts_Accessories&hash=item27be886503

    of corse these parts all depend on what engine you have now because i've read that some internal parts are not interchangeable even tho these engines are pretty much all the same basic design externally. buying a whole new engine will also give you a brand new magneto, intake manifold, sprocket, and clutch. but that's not saying that you'll get a good one, because as you know, ALL of these engines can have issues and it's a **** shoot whenever you buy one.
    just my opinion.
     
    Last edited: Mar 13, 2012
  15. Tyler6357

    Tyler6357 Member

    What to get

    I am totally willing to purchase a new 2 stroke engine (crappy time?). It's not like buying one of these things is going to break me. My current engine is this one (T80) --> http://www.ebay.com/itm/BRAND-NEW-6...035?pt=LH_DefaultDomain_0&hash=item35b867efd3. I don't mind spending a little more for a slightly better built engine. My engine is only 5 months old and I have driven it less than 500 miles. I was pretty disappointed that it broke so quickly. Are most of these 66cc, 2 stroke engines so poorly made? I was thinking about getting one of these Grubee Skyhawk motors---> http://www.kingsmotorbikes.com/grub...bike-motor-only-standard-finish_2909_prd1.htm Has anyone gotten one of these? Are they any good? Are they better than my T-80? I saw this one ----> http://www.bikeberry.com/jet-silver-66cc-80cc-bicycle-engine-kit.html It seems relatively inexpensive but I don't know anything about it. This one looks cheap----> http://www.ebay.com/itm/Motorized-B...436?pt=LH_DefaultDomain_0&hash=item27bd9552d4 but it is a pile of junk? I don't mind spending a little more if the thing will go 3000 miles before it breaks.
    My second problem is that I live in CA and none of the best vendors will send these engines to CA. We have an oppressive leftist government here that have outlawed sending 2 stroke engines into the state. The thing gets 150 mpg and they still claim it is bad for the environment. Leftists Suck!!
    I have a friend in NV that I might be able to send it to and then have them send it to me. What do you guys recommend? Which engine would you get if you were me? One of these or something else??
    Thanks
     
  16. Tyler6357

    Tyler6357 Member

    hmmmmm, none of my links worked. please copy and paste them into your browser. Sorry about that
     
  17. Porkchop

    Porkchop Member

    Yo Tyler, I'm by no means an expert on these engines. But from all that I've gathered here in the past couple of years as a member on this forum, people say that Grubees are the best. Thy may be, but how much better are they than all the others. Most folks say the 48cc engines are a little better in general than the 66cc engines. Mostly when it comes to vibration factor. Do a little research on Don Grubee if you haven't already. That will enlighten you on the Grubees and how they came about. As I said, I'm by no means an expert, Me personally, I have a friction drive with a Honda, 4 stroke 35cc engine. I have also used the same set up with a 52cc 2 stroke from the all time classic Harbor Freight auger. No quarrels with either engine. Good luck, and don't forget to post photos of what you find if you take the engine all the way down. You've got a good cliff hanger here that I think a lot of folks are interested in seeing and finding out what the problem is, or was ! Good luck !
     
    Last edited by a moderator: Dec 15, 2015
  18. Tyler6357

    Tyler6357 Member

    yeah, I don't know if I'm going to mess with this engine anymore. I don't think it's worth my time for an $80 engine. I will probably just see if I can get my friend in NV to send me a Grubee for $150. I just hope it really is worth 2 $80 junk engines.
     
    Last edited by a moderator: Dec 15, 2015
  19. Porkchop

    Porkchop Member

    If you're going to get a new engine, do us all a favor at tear down the bad one and post photos so we can all know what happened and/or know where those bearings came from. I think you hve eveyrone's curiosity up on this particular issue !
     
  20. Tyler6357

    Tyler6357 Member

    Al... I need your expert help!!

    Okay, I have gotten to step 29-30 where you take the 10 tooth gear off. It says:

    I don't think I have this tool. Is there any way to get it off without that tool or do I have to buy one? What exactly is it called? A "gear multi tool"? Where do I go? Home Depot??

    Thanks!
     
Loading...