Need help with repair

[jtennant]

Hi,
I live in a city who has no repair shop for gas motorized bikes. We need to repair a throttle assembly and cable and the piston is stuck. We found a on the side job guy that changed the throttle assembly and cable but did not hook up the white wire he 'does not know what it goes to'. omg, I am upset about this and want to learn to fix this myself and need help fast. I need to know how to repair throttle assembly and cable and hook it up correclty. Also he did not 'know' that the piston was stuck and at that point we took the bike and left fast. I cannot find any manuals or instructions, help!!
Thanks

 

[JonnyR]

the good question is what is stuck locking up the piston it could be alot of things have you looked in the clutch side to see if you lost a gear tooth and its jammed in gears if thats not it you have to pull the head off and look down into the cylinder to see if its screwed up in there

and yea most of us dont know what to do with the white wire so we ignore it and hope it goes away

 

[Harold_B]

Before we start dumping on the repair guy I'm curious if the engine ran before you brought it to him? If not, perhaps he assumed it did. If it did then it would be important to know how much he dis-assembled the motor.

 

[littletinman]

Tape or cap off the white wire. As to the throttle, can you post a picture of whats wrong with it?

As far as I know, the only place there are MB repair shops is out in Cali or finding a close MB member. The forum is the best help for everything though!

 

[bairdco]

if the piston is stuck, the throttle and white wire are the least of your concerns.

pistons don't get "stuck." it's either seized, or a bearing's destroyed, or something else that's probably not repairable. you can take the 4 nuts off the head and look inside, or pull it apart. it's pretty simple.

just to ease your mind on the white wire, it supposed to be used as power source for lights or something, and some older motors used to use it to wire up the kill switch.

the kill switch is better wired through the blue and black wires, and these engines have a hard time powering lights.

i actually go in an un-solder the wire and throw it away. most people just tape it up. it's basically useless.

 

[Harold_B]

"pistons don't get "stuck." it's either seized, or a bearing's destroyed, or something else that's probably not repairable. you can take the 4 nuts off the head and look inside, or pull it apart. it's pretty simple."

Pretty much what I was thinking with the possibility that if the engine was running before it went to the shop and the jug was removed maybe the repairman didn't know to align the rings before re-assembly.

 

[bigbutterbean]

Myself and a few others here do actually run headlights off the white wire, some also run tail lights. My tail light runs on AAA batteries, but my headlight is all white wire. I think some of the older engines did not do well with powering lights, but I think the newer style magneto is better, and that makes a difference. The trick is getting the right light to run off the white wire, and adjusting the idle may be necessary as well. I bought my headlight from wonderful creations on ebay.

 

[Bikeguy Joe]

telephone!

Where has all the good help gone?

 

[jtennant]

We bought from sons friend. We think that the gas/oil mixture caused it, because it was running before we put in gas and oil mixture, which was not a full gallon to the approx 7 oz that was put in, then it quit working. We took it to the bike guy not running. He did not do a diagnosis to why it was not running, only repaired the throttle assembly and cable, when we went to test it out it did not work so he opened the head and the piston does not move when the back wheel is moved (siezed?). He says to spray it with some liquid wrench and see if it will loosen and then clean it out, that it happened to him before. If it does not work, what parts would we need to buy to fix it? Is there any instructions to fix these types of issues any one may have?

 

[jtennant]

by the way, how do I locate a close MB member, I live in Tucson, AZ
Thanks for all of your support!!

 

[jtennant]

how much oil should we use per gallon for 60 cc engine?

 

[Bikeguy Joe]

If the piston doesn't move when the back wheel does, it's more likely a clutch problem or a sheared pin.

You want to mix the gas at between 24 to 1 (break in) or more like 40 to 1 for normal running. You'd better fire you "bike guy" if he fixed the throttle, but couldn't figure out the real problem.

 

[Dave31]

by the way, how do I locate a close MB member, I live in Tucson, AZ
Thanks for all of your support!!

Welcome to the forum jtennant from the West side...

 

[jtennant]

Hi,
Thanks for all of the input and support! We put some liquid wrench around the piston and it loosened, removed the case around the piston and can see that the piston looks good, it is something below it making it not move correctly. I am wondering if it is the bearing or other parts. Any ideas?
Thanks:

 

[jtennant]

Thanks Joe. My son took it apart last night with a little help with liquid wrench. The piston was not actually stuck on the casing around it, it is something below it not allowing for it to move freely. From what we are learning from all the great replies here, it seems to be a bearing or clutch part. The clutch engages and releases as it should so not sure it would be that causing it, but maybe so?

 

[nightcruiser]

Well, you shouldn't mix your gas willy-nilly like that, you should put X amount 2-stroke oil in 1 Gallon gas (or multiples thereof) so your mix is right. It seems if your mix was "not a full gallon to the approx 7 oz" of 2-STROKE(??) oil then your mix didn't have anything to do with the failure, best I can figure is your mix was around 16:1, which is too much oil. That mix may make the motor run funky but it wont make the bottom end seize, it would actually lubricate it better. For the record, on a motor that is already broke in I run 32:1 mix ratio, which is 4oz oil in 1 gallon gas. Others may run more or less oil (usually less), but something around 32:1 is proper. During break in of a new motor you should run something in the neighborhood of 18:1 to 24:1 (there are lots of theories on breakin), you run extra oil for the first couple hundred miles to help lubricate the dry parts on a new motor.

Since you have the top end off and the motor is still locked up, you either have something in the bottom end gone wrong, or something wrong on the gear side of the motor. I would pull the gear side cover and take a look in there, make sure there is nothing in there that would make those gears jam. If the problem is inside the case then you are up against a lot more work, so hopefully you will find something wrong with the gears. If you have the puller tool that comes with the motor you could pull the small bevel gear, this disconnects the crank shaft of the motor from the clutch (big bevel gear). If the piston wont move freely with the small bevel gear removed then something is hosed inside your crankcase....

Since this is all speculation I wont go on further, you'll have to dig in and provide more information on what you find. The good news is your gas/oil mix didn't kill your motor, bad news is a problem in the bottom end is not an easy fix.

 

[nightcruiser]

The piston was not actually stuck on the casing around it

BTW, the casing around the piston is called the "cylinder" or "jug" and the top that came off of it where the spark plug threads in is called the "head".
There is a little learning curve with these motors, but they are not all that tough to figure out, there really aren't all that many parts in these motors. If you are willing to work and learn you should be able to figure it out pretty quick.....

 

[jtennant]

Thanks so much! My son got the jug off and the piston looks ok, a little black on the top of it, but looks clean around the rest of it. When he manually tries to move it, it seems reluctant with the bearing, gear or something below it. I am trying to find parts somewhere, but they are very hard to find. I was thinking we can buy the parts for below the piston and replace them, but not sure yet what they are all called. The motor is 60cc do you know where I can order the parts?
Thanks!!

 

[jtennant]

can anyone provide me with the name parts of the lower end of the crankcase for me? Also, where can I get these parts for a 60 cc?

 

[Kcip]

http://www.grubeeinc.com/USA/Skyhawk Instructions.html check this site. Don't get frustrated. These are not terribly complex engines.