A few days past commented on eng quitting etc and figured fuel starvation was the problem, gas cap etc. Ran it today started the same thing and have ruled out fuel starvation. I think the mixture of fuel may be too lean and not enough lube to cylinder walls and seizes. It will fire right back up after only a moments rest so going to change mixture and put a little more oil mix. The engine does not have thirty miles on it probably less. Now the coaster brake started binding and has now bent the arm to a ninety degree bend. Yes lubed well and so on. I have a caliper on the rear anyway so doing away with the coaster. If the engine continues this road, going to change it out. Thought you would like to know and let me VENT some. gphil
Stalling engine
- Thread starter gphil
- Start date
Yes was running stopped with clutch engaged, fuel cap on then off as it started to lose power and it stopped, clutch held in. I have never had problems with two strokes other that a weed eater with a bad carb. lol The engine was hot........ gphil
I will recheck the clutch since this is a rather new build. It could need some readjusting although it seems to operate well. gphil
Raise the rear wheel off the ground, squeeze the clutch lever, (disengage the clutch) and spin the rear wheel. Does it spin free with only the normal chain/sprocket drag or does it try to turn the engine over? If the wheel spins free the clutch isn't dragging enough to stop the engine.
The engine isn't seizing because of lack of oil. It wouldn't start and run normally "after a few minutes". Many of us recommend an fuel/oil ratio of 32:1. That is sufficient oil for any 2 stroke, even a new one. Don't add oil to a mix already in the bike's tank. That will cause you more problems. Mix in a sepearte container and shake well.
By any chance is this one of the engines with the one piece, integral magneto/CDI? They are known for overheating and failing intermittently.
I've never experienced this problem but I've read reports of CDIs failing then working again after a cool down period. Not a common problem but no unheard of.
When you say "the engine was hot", how are measuring this? Any internal engine will get hot. Don't touch them after they've run
Tom
The engine isn't seizing because of lack of oil. It wouldn't start and run normally "after a few minutes". Many of us recommend an fuel/oil ratio of 32:1. That is sufficient oil for any 2 stroke, even a new one. Don't add oil to a mix already in the bike's tank. That will cause you more problems. Mix in a sepearte container and shake well.
By any chance is this one of the engines with the one piece, integral magneto/CDI? They are known for overheating and failing intermittently.
I've never experienced this problem but I've read reports of CDIs failing then working again after a cool down period. Not a common problem but no unheard of.
When you say "the engine was hot", how are measuring this? Any internal engine will get hot. Don't touch them after they've run
Tom
I'm thinking the same thing 2 door is... A bad magneto coil will fial intermittantly as well as a bad CDI unit. They'll run fine until the warm up and then start to cut out... usually on one second then off, let the engine rest for about 5 minutes and it fires right back up.
It's also very possible you got a bad CDI or mag coil in your new engine kit as I've had this problem before with a new Dax engine. I just got it built and installed, went to start it and it outright refused... checked for fuel and there was fuel in my carb so I pulled the plug, grounded it and pulled my start cord a few times... nothing. I was suspecting my new CDI so I put my old one back on and again, Nothing.
Next I did an ohm check on the blue and black wires where it measured dead open. Took the mag coil out and put in a known good one, connected it to the old CDI and it fired right up.
Check your mag coil by measuring the resistance between the black and the blue wire, it should be around 560 ohms, then black to ground (any bare metal on the engine) should read 0 ohms. If your blue wire is open or the resistance is really low, or zero resistance then the mag coil is bad. You may need to carry the meter with you and measure it right after it dies to catch it.
If the mag coil checks good, then check your CDI unit. I forgot what it should read, but hopefully someone else in here can help you with that part... unless you have another one that you know is good, then swap it out and see if the problem goes away. The mag coils don't like water or moisture, if water gets in there, you can pretty much kiss it goodbye. The CDI unit gets ruined by overtorquing the bolts holding it on, most the time one of the ears just breaks off, but it's potted in solid plastic so it can easily suffer internal damage. It also doesn't like vibration so solid mounting it to the frame is also a bad idea, a piece of rubber froman inner tube between the CDI unit and the frame will be enough to protect it as well as mounting it with a zip tie or 3 instead of the bracket.
One more trouble area in the ignition system is the stock spark plug boot, it can come loose or break internally and then the spark has to jump that gap plus the plug gap so it may or may not fire the plug it the stock boot went bad. Now to add more insult to injury here, if the boot is bad or broken and the spark has to jump this extra gap in there, it puts stress on the cdi and can cause the CDI to fail.
Also if you unscrew the boot off the wire and unscrew the wire off the CDI unit, cut off about 1/2" from each side and screw it all back together you'll get a better contact there.
As far as the engine being hot... Yes, these things run very hot... 280 to 320 degrees is about normal with 320 or so being right after a really hard run, with a new engine that's not fully broken in, it'll run hotter too, that's why it's not recommended to ride more than about 30 minutes then let it cool. Best way to measure the temperature is with an infrared "point and shoot" type thermometer or a cylinder head temp gauge with the probe on the spark plug base. Keep your operating temp well below 400 degrees because that's where the aluminum starts to lose it's strength... 320 to 360 is ok for short bursts, but above 360 should be avoided.
Hope this helps.
It's also very possible you got a bad CDI or mag coil in your new engine kit as I've had this problem before with a new Dax engine. I just got it built and installed, went to start it and it outright refused... checked for fuel and there was fuel in my carb so I pulled the plug, grounded it and pulled my start cord a few times... nothing. I was suspecting my new CDI so I put my old one back on and again, Nothing.
Next I did an ohm check on the blue and black wires where it measured dead open. Took the mag coil out and put in a known good one, connected it to the old CDI and it fired right up.
Check your mag coil by measuring the resistance between the black and the blue wire, it should be around 560 ohms, then black to ground (any bare metal on the engine) should read 0 ohms. If your blue wire is open or the resistance is really low, or zero resistance then the mag coil is bad. You may need to carry the meter with you and measure it right after it dies to catch it.
If the mag coil checks good, then check your CDI unit. I forgot what it should read, but hopefully someone else in here can help you with that part... unless you have another one that you know is good, then swap it out and see if the problem goes away. The mag coils don't like water or moisture, if water gets in there, you can pretty much kiss it goodbye. The CDI unit gets ruined by overtorquing the bolts holding it on, most the time one of the ears just breaks off, but it's potted in solid plastic so it can easily suffer internal damage. It also doesn't like vibration so solid mounting it to the frame is also a bad idea, a piece of rubber froman inner tube between the CDI unit and the frame will be enough to protect it as well as mounting it with a zip tie or 3 instead of the bracket.
One more trouble area in the ignition system is the stock spark plug boot, it can come loose or break internally and then the spark has to jump that gap plus the plug gap so it may or may not fire the plug it the stock boot went bad. Now to add more insult to injury here, if the boot is bad or broken and the spark has to jump this extra gap in there, it puts stress on the cdi and can cause the CDI to fail.
Also if you unscrew the boot off the wire and unscrew the wire off the CDI unit, cut off about 1/2" from each side and screw it all back together you'll get a better contact there.
As far as the engine being hot... Yes, these things run very hot... 280 to 320 degrees is about normal with 320 or so being right after a really hard run, with a new engine that's not fully broken in, it'll run hotter too, that's why it's not recommended to ride more than about 30 minutes then let it cool. Best way to measure the temperature is with an infrared "point and shoot" type thermometer or a cylinder head temp gauge with the probe on the spark plug base. Keep your operating temp well below 400 degrees because that's where the aluminum starts to lose it's strength... 320 to 360 is ok for short bursts, but above 360 should be avoided.
Hope this helps.
Thanks for all the great info. By hot, it just seemed hotter than usual but then I had ridden for a short burst down the road , not far at all and no where near wot , just puttering along then stopped and stood beside it therefor no air flow. Yes the wheel will turn freely off the floor with clutch held in. I will dig into the other areas next week . I do not know what type mag I have, never have had the cover off. Tell ya what guys going to be a full fledged mechanic after all this. Never was one to just build and go, had to always work on things. I will get back and once more thanks, can always count on ya. gphil
Wanted to add, never changed out the wire, boot or anything like that. Sill stock. I have read in the past to "change all that with good grade auto wire" etc. Should I ? The time between stop and restart was less than 1 and 1/2 minutes. Do not think I put rubber on CDI mount either.
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God, questions keep rising in my thoughts, last one. Can you take the internals ,( paws ) out of a coaster brake and reuse it that way or does it mean a new wheel and hub?
Man I hadn't messed with a coaster brake in over 30 years... I think that arm needs to stay connected tho or it'll work it's way loose internally if I remember right, maybe someone else will help and let you know if you can gut it out. If I remember right tho, those pawls have to stay in there...
