Bike is only firing with choke up !

[lilchunkyboy]

i have a 80cc 2 stroke. I ride it regularly. just after riding it, i went inside for a few hours and came out to start it. It only fires with the choke up, as soon as flick it down its just cranking and not firing, when i give it the throttle with the choke down it changes tone quite a bit but doesnt fire . I was first drawn to a carb problem,i checked for spark with placing it on head,and it sparked. The carb was clean, i blew through each jet,and theres nothing obstructing. I changed the spark plug, wire, and soldered connections, could it be spark ? too much resistance,e.g it fires outside, but not inside. i cant get my head around it, within a few hours it can develop a problem like this, fires quite nice with the choke up. ANY SOLUTIONS ?

 

[Greg58]

Sounds like a air leak somewhere.

 

[lilchunkyboy]

i ensured the carb and the manifold were tight, where the exhaust mounts, theres a small gap due to the frame,not sure that it matters. i recently took the head off, ensured that the head bolts are tightened down.

 

[lilchunkyboy]

the jet is loose, and off centred , i took the carb apart so, I’m not sure if that’s there because I took apart the carb, or it’s been loose the whole time.

 

[Greg58]

You have to take the bowl off to check the jet.

 

[lilchunkyboy]

I had taken the bowl off previously.

 

[Testname111]

To much oil in you're gas, dump some from tank and line, add more gas......I use 50/50 mix synthetic car oil and vegetable oil

 

[lilchunkyboy]

I thought I would have to add more. The petrol in the tank looks pretty clear.

 

[Testname111]

If all fails with the carb try new electrical system from bikeberry.com super magneto and stage 1 cdi ( the cheap China ones suck and China cdi)

 

[Venice Motor Bikes]

It definitely sounds like a carb issue... Take the carb apart & post some pictures.

 

[lilchunkyboy]

If all fails with the carb try new electrical system from bikeberry.com super magneto and stage 1 cdi ( the cheap China ones suck and China cdi)

It definitely sounds like a carb issue... Take the carb apart & post some pictures.

Ok

 

[Testname111]

Don't knock it till u try

 

[Venice Motor Bikes]

Actually... Those pictures you posted look like the 'jet holder' inside the float bowl unscrewed (& fell out)!!

Take off the float bowl & check it out!

 

[Testname111]

Turn Left danica-patrick

 

[Greg58]

To much oil in you're gas, dump some from tank and line, add more gas......I use 50/50 mix synthetic car oil and vegetable oil

Snake oil?

 

[lilchunkyboy]

Should the fuel petcock be see through ? looks like there’s something metal blocking it.

 

[Greg58]

There’s a metal strainer that is supposed to be a filter, if you have a in-line filter you can remove it.

 

[lilchunkyboy]

Ok, the fuel wasn’t flowing well, I checked the petcock and it was dirty.

 

[Greg58]

Most petcocks have a reserve like motorcycles do, there should be two openings on the petcock with one tube taller than the other.

 

[lilchunkyboy]

Yes, sir