80/66 cc engine not starting

[Petter]

Okay, thanks for the tips. I will make a video about this tomorrow. If the timing of the spark is the issue, how do I sort this out?

 

[Petter]

I can make a video on the magneto tomorrow, but when I first tried to start it when I just got it it ran for like 10 minutes, what do you think have happened that messed up the timing?

 

[Petter]

The weird thing is when I just had build the bike about two weeks ago, it started on the third attempt. I’ve left a video of my friend trying it at the end of the message. However we didn’t want to keep it going for too long as the engine was brand new. We stopped the engine after approximately 10 minutes, and let it cool off. After 20 minutes we tried to start it again but could not. The very next day I decided to look at it and start it over and over, I discovered the clutch was slipping. I went and innstalled the rubber piece so the piston was engaged with the wheel again. However i haven’t got I going since. I goes for 3-4 seconds every once in a while but no more, and definitely not when I riding it, only spin the wheel by hand. I went and ordered a new carb as the previous one started leaking after I tried to adjust it. With the new carb the bike have been running on time, but not while I ride it. I have left both videos below. I want to add that when me and my grandfather actually got it started we tried for a very long time, maybe 45 minutes. There was several incidents where it started, but just cut off after 4 seconds as in the clip I’ve sent earlier. We got lucky on time and I kept going. (Also I know the chain is loose, I have sorter this out.) Currently I’m struggling to find the problem, and appreciate your help.

 

[Petter]

Thanks for the suggestion, I ask many questions now as I want to make a detailed video tomorrow in case you can see the problem. Do I just unplug the green wire? Also do you want me to check for anything with the cdi or magneto loop set?

 

[Petter]

Okay thank you, I will send a video tomorrow. I have some issues understanding exactly what to with the cdi and magneto as English is not my first language but I will try.

 

[Wrench]

English is not my first language but I will try.

Your English spelling, punctuation and sentence structure is good, is that due to spell check?

 

[Petter]

I mean my English is okay, and the spelling correction sure helps! However the very specific concept words are a bit difficult to understand, especially when I don’t know what their called in my foreign language either. Also I’m not very experienced with engines in general.

 

[wolframore]

Do you have a multimeter?
Check the spark plug from tip to tip. Check gap = 0.6mm.
Check your CDI from plug boot to both wire (one at a time)
Check your magneto wire blue to black wire

Make sure everything is disconnected when you do above measurements

First thing I do is throw out the spark plug and replace with NGK B6HS
I also cut the garbage spark boot off and put a NGK LZFH

Make sure your magneto coil is over 300 Ω

You can’t see what magnet you have until you take the large nut off. But do the measurements above before you go further taking things apart.

It could be poor electrical contact from something above.

Silly question are you mixing oil in your gasoline?

 

[Petter]

Thanks for detailed list, here is a video where I test out different things. I’m sorry if it’s a bit confusing, or I don’t show the correct thing but I tried.

 

[wolframore]

take the spark plug and place the screw part on the engine (with everything else connected) and turn the motor to see if you can see a spark, it should be done in fairly dark area. It really sounds like you have a weak spark. I would suspect CDI, magneto or magnet. It really helps to have an inexpensive multimeter to check the electrical system. if you do get a spark, then I would suspect an air leak at the carb/ intake joint.