nope. no spark. checked everything with multimeter, past the cdi i get no reading. i'm not sure what would have burnt it out. it's sealed - there's no way water got in it.
48 cc Bike not running with VIDEO
- Thread starter stroker
- Start date
you didn't need to tear apart the spark plug wire that you bought.
the original plug wire just unscrews from the cdi box, and then you can just screw the new wire in, in the old wires place.
twist the wire counter clock wise at the cdi to unscrew it.
if you had spark at the plug wire before, you should have spark at the wire now. weather you have spark at the plug is a different thing tho.
you may just have a bad spark plug.
is the white wire from the magneto hooked to anything (like a light)?
if so, this will take power away from the magneto and take away your spark.
there is a way for water to get into the magneto, which is where the power comes from to make the cdi work.
also, check to make sure that none of the wire connectors are broken or touching the frame.
the best thing to do is cut off those push together connectors and solder the wires together, then cover them with heat shrink.
those push together connectors are junk.
the original plug wire just unscrews from the cdi box, and then you can just screw the new wire in, in the old wires place.
twist the wire counter clock wise at the cdi to unscrew it.
if you had spark at the plug wire before, you should have spark at the wire now. weather you have spark at the plug is a different thing tho.
you may just have a bad spark plug.
is the white wire from the magneto hooked to anything (like a light)?
if so, this will take power away from the magneto and take away your spark.
there is a way for water to get into the magneto, which is where the power comes from to make the cdi work.
also, check to make sure that none of the wire connectors are broken or touching the frame.
the best thing to do is cut off those push together connectors and solder the wires together, then cover them with heat shrink.
those push together connectors are junk.
that's the thing. i read voltage at the magnito, at the wires comming out of the mag where they connect to the cdi. however, i get no reading at the spark plug wire, at the connecter inside the boot, or the spark plug. so i read voltage before the cdi and not after. the cdi is compleatly sealed and i had no luck unscrewing the wire.
hmmm, maybe start checking the wiring going to the cdi.
those push together connectors are known to fail....they are junk.
if the wiring looks ok, and no bare wires are touching the frame, maybe pull the cdi box off of the bike that runs, and put it on the one that doesn't run.
at least then if it runs, it will tell you that you need a new cdi.
Just a thought.
those push together connectors are known to fail....they are junk.
if the wiring looks ok, and no bare wires are touching the frame, maybe pull the cdi box off of the bike that runs, and put it on the one that doesn't run.
at least then if it runs, it will tell you that you need a new cdi.
Just a thought.
OK, I know it's been a while since I posted about this, but I've been slowly working on troubleshooting this bike.
I think I've got it narrowed down to the clutch/bottom end. The reason that I say this is because I can get the motor to run and sound like a 2-stroke should at high RPMs. But this is only with the clutch disengaged (handle pulled). With the clutch engaged the bike sounds kinda like it does in the video when you hear me twisting the throttle towards the end. It barely has any power, and sounds bogged down, almost like a 4 stroke. With the clutch disengaged I can get it revved up to that high 2-stroke whin-whin-whin. But the bike also does not want to idle with the clutch in (idle screw on the carb. also all the way in).
Another reason I think it is the clutch is that the previous owner really monkeyed with the cable to the point where the end was completely frayed and unusable so I took it off and have no cable/ clutch handle. What I've been doing to test the bike is push the bar in (the clutch bar over the motor drive sprocket, (it stays pushed in, is that bad?)) and then flick it out to engage the clutch/start the motor.
I also noticed when I pulled off the clutch cover there was quite a bit of strong smelling dirty oil/grease (maybe gas mixture?) on the inside of the cover.
I tried spinning the flower nut out a bit, but so far the did not help, would doing that more help? Is there such a thing as too much clutch engagement?
Thanks for helping out a rookie!
I think I've got it narrowed down to the clutch/bottom end. The reason that I say this is because I can get the motor to run and sound like a 2-stroke should at high RPMs. But this is only with the clutch disengaged (handle pulled). With the clutch engaged the bike sounds kinda like it does in the video when you hear me twisting the throttle towards the end. It barely has any power, and sounds bogged down, almost like a 4 stroke. With the clutch disengaged I can get it revved up to that high 2-stroke whin-whin-whin. But the bike also does not want to idle with the clutch in (idle screw on the carb. also all the way in).
Another reason I think it is the clutch is that the previous owner really monkeyed with the cable to the point where the end was completely frayed and unusable so I took it off and have no cable/ clutch handle. What I've been doing to test the bike is push the bar in (the clutch bar over the motor drive sprocket, (it stays pushed in, is that bad?)) and then flick it out to engage the clutch/start the motor.
I also noticed when I pulled off the clutch cover there was quite a bit of strong smelling dirty oil/grease (maybe gas mixture?) on the inside of the cover.
I tried spinning the flower nut out a bit, but so far the did not help, would doing that more help? Is there such a thing as too much clutch engagement?
Thanks for helping out a rookie!
The clutch arm should not stay in after you push it, it should rebound back out when pressure is taken away, so it does sound like you have something going on with the clutch...
Kinda hard to diagnose what could be going on with a second hand bike through words in a forum, some pics would probably be helpful. That said, you want to make sure the bearing is in there under the bucking bar first off. Second, go get yourself a new cable and connect back the clutch, YOU NEED A CLUTCH!!! LOL I find it hard to conceive of how you would start and ride a MB properly without a clutch. After you get your clutch lever working see how it rides then and report back....
Kinda hard to diagnose what could be going on with a second hand bike through words in a forum, some pics would probably be helpful. That said, you want to make sure the bearing is in there under the bucking bar first off. Second, go get yourself a new cable and connect back the clutch, YOU NEED A CLUTCH!!! LOL I find it hard to conceive of how you would start and ride a MB properly without a clutch. After you get your clutch lever working see how it rides then and report back....
The chinese grease does smell bad but if it smells like fuel it's not normal and you might have a clutch side seal failure. When that happens you will notice oily stuff coming out of the crankcase throught the seal, it might be hard to see since it's behind the small gear but in most cases you will an oil film sipping down under the gear; I mention this because a seal failure can let air in and primary compression out making the engine underpowered and prone to failure.
Bought a replacement cable on ebay but it was too short. So I'm going to hold off on that until I'm sure I can get this motor to work, or else I'm gonna buy a whole new kit (that comes with a new clutch cable!).
The clutch arm does rebound if I don't push it in all the way, but I push it in real far (it hits the carb.) so it will stay in so I can pedal and flick it out to start the motor.
The clutch arm does rebound if I don't push it in all the way, but I push it in real far (it hits the carb.) so it will stay in so I can pedal and flick it out to start the motor.
Just go to a local bicycle store and buy a cable from them that is long enough. The inner cable and the outer cable housing that comes with the kit is crap anyways. You can get a much better cable from a bike shop, a better cable will also help reduce the amount of force required to pull in the clutch. Just ask the bike guy about cables and they should lay out the differenced for you, the lined ones work real smooth compared what comes with the kits. If your worried about it being strong enough or the right length just bring what's left of your old cable with for measurements...
heck, just go to wal mart and buy yourself a whole cable kit for a multi speed bike.
these kits come with 2 shifter cables, 2 brake cables, and ends to cap the cable and cable housing (if you cut the housing to shorten the length, you need to cap the end of the housing or the housing will start to unravel on you.)
I think the whole kit was $9.96...can't beat that because these cables are better quality than the clutch cables that come in the engine kits.
even tho they are brake and shifter cables, they'll still work as a clutch cable.
they are the same size and have the same end that goes into the clutch lever on the handlebars.
these cables will also work as throttle cables, but you have to make the end lugs because the ones that are on the cables are too big.
the end on the throttle cable that goes into the carb slide is pretty small, so you'd have to make a new one with silver solder....very simple to do.
these kits come with 2 shifter cables, 2 brake cables, and ends to cap the cable and cable housing (if you cut the housing to shorten the length, you need to cap the end of the housing or the housing will start to unravel on you.)
I think the whole kit was $9.96...can't beat that because these cables are better quality than the clutch cables that come in the engine kits.
even tho they are brake and shifter cables, they'll still work as a clutch cable.
they are the same size and have the same end that goes into the clutch lever on the handlebars.
these cables will also work as throttle cables, but you have to make the end lugs because the ones that are on the cables are too big.
the end on the throttle cable that goes into the carb slide is pretty small, so you'd have to make a new one with silver solder....very simple to do.
Last edited:
I was having the same problem sounded just like that, maybe no compression,.?
my head (4 top nuts) wasn't seated correctly to the cylinder, 1 side was tightened before the other I guess, so I loosened it up, got the head seated real good, hand tightened the nuts then rotated the socket as i tightened them all down, started right up,..! good luck,...!
my head (4 top nuts) wasn't seated correctly to the cylinder, 1 side was tightened before the other I guess, so I loosened it up, got the head seated real good, hand tightened the nuts then rotated the socket as i tightened them all down, started right up,..! good luck,...!
Welcome to the forum ajslim...
http://motorbicycling.com/showthread.php?t=24873
http://motorbicycling.com/showthread.php?t=10560
