New bike doesn't start

Gerard Andrade

New Member
Joined
Nov 3, 2016
Messages
14
Hello everyone, I have a problem with my 50 cc 2 stroke engine not starting. First a little background to help paint the picture. I'm a car enthusiast and love engines, but due to financial complications I can't afford to get my license and decided to build a motorized bycicle since it's a lot cheaper to maintain and I had a bike lying around. So I ordered one (a 50CC) and it shipped quickly. Installation could have gone smoother but the engine is on and everything is in place. When I got gas and oil I mixed it to a 16:1 ratio. (That's what the instruction manual called for) But anyway, I start pedaling my bike and let the clutch out and it puffs and sounds like it is started but when I pull the clutch in the piston starts moving. At first I though the fuel wasn't getting to it but that was short lived when I saw gas dripping out of the exhaust. Then I thought my spark plug wasn't firing and this may be the case but not sure. When I try to get spark it doesn't show but when I use my finger the jolt is very strong. Can someone help point me in the right direction?
 


Frankenstein

In memory of Frankenstein 1991 - 2018
Joined
Jun 24, 2016
Messages
5,077
Hello everyone, I have a problem with my 50 cc 2 stroke engine not starting. First a little background to help paint the picture. I'm a car enthusiast and love engines, but due to financial complications I can't afford to get my license and decided to build a motorized bycicle since it's a lot cheaper to maintain and I had a bike lying around. So I ordered one (a 50CC) and it shipped quickly. Installation could have gone smoother but the engine is on and everything is in place. When I got gas and oil I mixed it to a 16:1 ratio. (That's what the instruction manual called for) But anyway, I start pedaling my bike and let the clutch out and it puffs and sounds like it is started but when I pull the clutch in the piston starts moving. At first I though the fuel wasn't getting to it but that was short lived when I saw gas dripping out of the exhaust. Then I thought my spark plug wasn't firing and this may be the case but not sure. When I try to get spark it doesn't show but when I use my finger the jolt is very strong. Can someone help point me in the right direction?
Perhaps too much a gap or not enough spark, I think it's about 3000 volts or so to jump a 1mm gap in plain air. Under pressure in a gas and air environment it's significantly higher. If the cdi only gives you 2000 volts you might not see anything outside a motor, but that's still way more than enough that you could feel easily. Now you say it's a very strong jolt? It should have felt like something you won't do again for several months if you can help it, not just a strong jolt. . .

I remember when I had an air leak in my intake, I pulled the spark plug cable to stop the engine but since it got so lean it just kept running and proceeding to shock my hand using my inner leg as ground. That definitely sucked and I was absolutely awake for the rest of the day. Never want to repeat that fun adventure .
 

66ccCruiser

New Member
Joined
Aug 4, 2014
Messages
24
Change the plug, possibly fouled, 16 to 1 mix is pretty oiley and maybe the plug didn't like it..Reminds me of a story, I had someone on Craigslist have a problem with their bike not starting after putting it together and were going to sell it..I lived nearby and stopped in to see whatsup,,,the clutch wasn't engaging enough to turn the motor over even though it sounded like it was when this guy was trying to start it...I got on it and thought the same thing for a moment myself then we took the clutch cover off and could see it not working enough...cured it and it started right up....This guy had spent all week end trying to start it with all kinds of people helping him and never though about the clutch slippin, just one of those things...
 

skyash

Active Member
Joined
Jun 26, 2015
Messages
755
Do you think it's flooding if you got petrol out the muffler ? ..and yes a shock from a 66cc is like a gun shot I will never do it again in my life .I have had to pull the plug wire before that's a couple of shots lol
 

crassius

Well-Known Member
Joined
Jul 23, 2012
Messages
4,572
when motor is running, there's a lot of voltage there, at cranking speeds not so much
 

Gerard Andrade

New Member
Joined
Nov 3, 2016
Messages
14
Perhaps too much a gap or not enough spark, I think it's about 3000 volts or so to jump a 1mm gap in plain air. Under pressure in a gas and air environment it's significantly higher. If the cdi only gives you 2000 volts you might not see anything outside a motor, but that's still way more than enough that you could feel easily. Now you say it's a very strong jolt? It should have felt like something you won't do again for several months if you can help it, not just a strong jolt. . .

I remember when I had an air leak in my intake, I pulled the spark plug cable to stop the engine but since it got so lean it just kept running and proceeding to shock my hand using my inner leg as ground. That definitely sucked and I was absolutely awake for the rest of the day. Never want to repeat that fun adventure .
What should the gap be?
 

Gerard Andrade

New Member
Joined
Nov 3, 2016
Messages
14
Change the plug, possibly fouled, 16 to 1 mix is pretty oiley and maybe the plug didn't like it..Reminds me of a story, I had someone on Craigslist have a problem with their bike not starting after putting it together and were going to sell it..I lived nearby and stopped in to see whatsup,,,the clutch wasn't engaging enough to turn the motor over even though it sounded like it was when this guy was trying to start it...I got on it and thought the same thing for a moment myself then we took the clutch cover off and could see it not working enough...cured it and it started right up....This guy had spent all week end trying to start it with all kinds of people helping him and never though about the clutch slippin, just one of those things...
How do I know if it's slipping?
 

66ccCruiser

New Member
Joined
Aug 4, 2014
Messages
24
How do I know if it's slipping?
Ya when the cover is off on the clutch side you will physically see it not turning over or partially turning over when pedaling and dropping the clutch...you can confirm with taking the plug out and turning over and then with plug in, to see the difference if it is just slipping enough to create not enough rpm's to get running..
Do you think it's flooding if you got petrol out the muffler ? ..and yes a shock from a 66cc is like a gun shot I will never do it again in my life .I have had to pull the plug wire before that's a couple of shots lol
Your flooding and possibly plug is fouled and won't spark to burn that fuel running through your system all the way through to the exhaust, sorry to see your having that issue....make sure your choke is off by taking the air filter off and making sure lever is in the right position to be open ..even try to start with air cleaner off as well...and attempt to start with choke off...throttle open...If trying to start it repeatedly with choke on it got too much fuel and has propably fouled the plug and too much fuel in the system....Good Luck Partner..
 
Last edited:

66ccCruiser

New Member
Joined
Aug 4, 2014
Messages
24
# 1. How to Adjust Clutch if signs of slipping or squealing is encountered: A) Disengage clutch by pulling handle bar clutch lever inward and lock into catch lock. B) Remove right side engine clutch cover and remove small locking screw on center *Clutch Adjust Nut. C) Pull clutch arm on left rear engine inward. Back off *Clutch Adjust Nut ¼ turn counterclockwise. D) Release handlebar clutch lever and check for slight 1/16” free-play on engine clutch arm. E) Readjust *Clutch Adjust Nut as required to get required 1/6” clutch arm free play. F) Tighten *Clutch Adjust Nut on clutch plate clockwise until just snug. G) Then re-install small locking screw in outer edge of *Clutch Adjust Nut . Just make sure that when you adjust your clutch that it rolls relatively freely when clutch lever is pulled in lock position....
 
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