80cc engine wont start

[Dylangunvar]

Hi all.
Bike started for 10 seconds on first use then cut out and after 3 more short starts it stopped and locked up after hours of investigating it was the chain caught in the engine sprocket it had jumped a tooth and pocked up like a triangle blocked it from moving.
Tried starting again and it now doesnt even start a little bit, i tested the spark plug and it sparks just about, fuel is getting to carb.
Not sure why it just wont start. Its also very hard to pedal when i realise the clutch when pedaling, as soon as i release the clutch it quickly comes to a stop. Would appreciate any ideas thanks

 

[Dylangunvar]

Ohh and i tested the kill switch with a multimeter, the continuity between the 2 wires

 

[Greg58]

Welcome to the forum, try taking the sparkplug out and pedal around with the clutch out, you should hear the engine cycling. This will clear the engine of excess fuel in case it was flooded. Try starting without the choke or 1/2 choke, some need very little to start. You'll have to learn what works with yours, I have three right now and all are different to start.

 

[Dylangunvar]

Welcome to the forum, try taking the sparkplug out and pedal around with the clutch out, you should hear the engine cycling. This will clear the engine of excess fuel in case it was flooded. Try starting without the choke or 1/2 choke, some need very little to start. You'll have to learn what works with yours, I have three right now and all are different to start.

I did that and ran the bike around without the compression, emptied out the fuel from the float chamber and took the bike to a big hill. Got some good speed and after about 4 attempts it finally started to spark a little, iv learnt it wont start endless i gave the throttle is on max then it starts to roll over and spark, once i got started running smoothly, apart from having soo much fun, i noticed the engine cuts out as soon as I disengage the clutch or if i go below 5 mph, no idea which screw is the idle as i see lots of people calling the brass screw a mixture screw. I have a NT Carb btw.
Thanks a bunch

 

[Greg58]

On the nt the screw on the side is idle,.

 

[Dylangunvar]

On the nt the screw on the side is idle,.

Ahh makes sense.
Only probable is now it wont start again, ran for about 10miles yesterday and now its not even starting at all, not even igniting and the piston moving back down, checked the spark and it gives spark, maybe fuel/air mixture?

 

[Greg58]

Some engines are hard to start at first, repeat what worked the first time and see it will start. After you go through a couple of tank of fuel it will get better.

 

[Greg58]

What fuel ratio are you using? The 16/1 recommended is way too much oil, I start at 24/1 with good oil for air cooled engines such as a chain saw, then after a couple of tanks I switch to 32/1.

 

[Dylangunvar]

What fuel ratio are you using? The 16/1 recommended is way too much oil, I start at 24/1 with good oil for air cooled engines such as a chain saw, then after a couple of tanks I switch to 32/1.

Im using 16:1 as advised in the build guide. But maybe i will top up with a little petrol, already got about 1/2 a tank in there. Im using 2 stroke mineral oil wilko brand (uk home and hardware) it says specifications: API TV , JASO FB

 

[Greg58]

16/1 has been recommended for years in these kits, if you read in the instructions it says you can use regular 30w motor oil. That’s why the oil ratio is at 16/1.

 

[Dylangunvar]

Should i change the oil then? Or top up more petrol and do 20/1 ratios from now on? Thanks

 

[Greg58]

It’s hard to adjust the ratio, don’t add to the tank, I would mix at 24/1 and change to it.