I have a new motor and after I installed it she ran good for the first 8 rides or so. And then all of the sudden it will not stay running. I can get it to start but as soon as I disengage the clutch to let it idle it dies. If I leave clutch engaged and try to give it some throttle it also dies. Can someone please help me.
Won't stay running anymore
- Thread starter BoogieMan
- Start date
Welcome to the forum, start with the basics first. Make sure everything is tight, head nuts and carburetor can loosen. Clean or replace the spark plug, if you replace the plug a b6hs gapped at 25-26 works well. I assume you have a 66cc 2 stroke, if not tell us what you have and someone will help.
Everything is tight, plug is clean and gapped at 24, I have even drained gas tanked and used new, clean fuel. And I have an 80cc.
What they call a 80cc is actually a 66cc, I would start with cleaning the carburetor, you could have debris restricting fuel flow. What fuel mixture are you using? 24/1 is good for the first couple of tanks and 32/1 after that with a 2 cycle oil for air cooled engines. Try turning the idle screw in a couple of turns to see if it will run long enough to warm up, a carburetor engine has to warm to run right. Remove the plug and connect it to the cdi and lay it on the head to check for spark, roll the bike with the clutch out and watch the plug for spark. It should have a good spark you can see.
Last edited:
Boogie Man, Welcome!
For starters , take Gregs advice and confirm spark.
"What I don't get is when I engage the clutch it immediately dies".
Are you aware you must be peddalled up to speed before engaging the clutch? This is not a featherable clutch. Clutch is Engaged or Disengaged. You can't start from a complete stop. You must be in forward motion (a couple miles per hour or so) before engaging the clutch. I know a fella that thought it was that much like a dirt bike.
"It actually starts running it just won't stay running."
Twist the throttle control and let it snap back. You should actually hear the function of the barrel in the carb. Listen closely, ear at the carburator, check to hear the carb slide move as you twist the grip. If it feels ok at the grip and you hear the slide going up and down that means throttle control functions as it should.
"It actually starts running it just won't stay running."
I would then pull the bowl, 2 screws at carb top. Carefully remove the bowl, don't hurt the gasket and look to see that the jet didn't fall out and is laying in the bottom of the bowl. Seen this a couple time lately. If all looks as it should, carefully reassemble. Stay in touch.
For starters , take Gregs advice and confirm spark.
"What I don't get is when I engage the clutch it immediately dies".
Are you aware you must be peddalled up to speed before engaging the clutch? This is not a featherable clutch. Clutch is Engaged or Disengaged. You can't start from a complete stop. You must be in forward motion (a couple miles per hour or so) before engaging the clutch. I know a fella that thought it was that much like a dirt bike.
"It actually starts running it just won't stay running."
Twist the throttle control and let it snap back. You should actually hear the function of the barrel in the carb. Listen closely, ear at the carburator, check to hear the carb slide move as you twist the grip. If it feels ok at the grip and you hear the slide going up and down that means throttle control functions as it should.
"It actually starts running it just won't stay running."
I would then pull the bowl, 2 screws at carb top. Carefully remove the bowl, don't hurt the gasket and look to see that the jet didn't fall out and is laying in the bottom of the bowl. Seen this a couple time lately. If all looks as it should, carefully reassemble. Stay in touch.
Last edited:
Ok carb is cleaned, I have spark, choke is not on but still won't stay running. I can get it to turn over but will only stay running if I am peddling the bike. I do not know what else to do. Any and All help in this matter will be greatly appreciated.
Forget compression for now! Remove the Bowl, 2 screws at carb top. Carefully remove the bowl, don't hurt the gasket and look to see that the jet didn't fall out and is laying in the bottom of the bowl. Seen this a couple times recently on the new 80's (66).
Excellent carb info found here on this forum at this link.
https://motorbicycling.com/threads/motorized-bicycle-carburetor-install-and-rebuild.302/
Excellent carb info found here on this forum at this link.
https://motorbicycling.com/threads/motorized-bicycle-carburetor-install-and-rebuild.302/
Last edited:
Follow this thread on compression. I hope it helps ya. Good Luck.
https://motorbicycling.com/threads/what-is-an-acceptable-compression-of-a-stock-motor.40642/
https://motorbicycling.com/threads/what-is-an-acceptable-compression-of-a-stock-motor.40642/
Oh and one more thing just occured to me. On the drive side of motor, pull the 4 screws holding the mag cover. remove the mag cover and check to see if key in rotor is not sheared or slightly off from where it should be. Here's a thread concerning the Magneto which may or may not answer some questions.
https://motorbicycling.com/threads/magneto-problems.59247/
https://motorbicycling.com/threads/magneto-problems.59247/
Last edited:
To answer directly NO. This being a new engine and it only having 8 rides or so - I doubt you have an issue with compression UNLESS you didn't put oil in your gas. Or, to ask What would cause NO Compression? A blown out seal. There are 2 to be concerned with. One behind the clutch plate and one behind the Magneto rotor. Pull the clutch cover - remove 5 screws. is there fuel in this area at the bottom of case? If so could be a blown out seal there resulting in loss of compression. If not pull the magneto/rotor cover. I'm assuming you have checked this area already because a sheared or slipped key will give you a spark but timing will be off, creating a no Start Condition.
Is there is fuel / seepage / wet in there? If so, could be a blown out seal there resulting in loss of compression. Look all around the engine case halves for seepage. Check your engine Head Gasket. Is there seepage where the head meets the cylinder if so, pull the Head off the engine and inspect the gasket for a blow out. At this point to settle your Compression question without a compression gauge, rotate the engine so piston is at its lowest point, then with a flashlight Inspect carefully the cylinder walls for scars. If you got scars in there, you got bigger problems.
Once again - I provided you with a link specific to compression and how much of it is needed for these engines to run.
If you insist - in your belief compression loss is your problem.Save yourself time and frustration. Buy or borrow one of these.
https://www.harborfreight.com/compression-test-kit-8-pc-62638.html. Go to your local auto mechanic / service station and offer to pay for a lunch
if they would check it for you.
Is there is fuel / seepage / wet in there? If so, could be a blown out seal there resulting in loss of compression. Look all around the engine case halves for seepage. Check your engine Head Gasket. Is there seepage where the head meets the cylinder if so, pull the Head off the engine and inspect the gasket for a blow out. At this point to settle your Compression question without a compression gauge, rotate the engine so piston is at its lowest point, then with a flashlight Inspect carefully the cylinder walls for scars. If you got scars in there, you got bigger problems.
Once again - I provided you with a link specific to compression and how much of it is needed for these engines to run.
If you insist - in your belief compression loss is your problem.Save yourself time and frustration. Buy or borrow one of these.
https://www.harborfreight.com/compression-test-kit-8-pc-62638.html. Go to your local auto mechanic / service station and offer to pay for a lunch
if they would check it for you.
