Scoot suddenly won't run

[drbob]

My scoot is a 72cc roketa. Didnt ride it last week due to weather. Went to ride it the other day and it would start but would bog and spurt if given throttle. Checked air filter, carb, spark plug etc and switched them all for back ups and still same issue so I figured it was bad gas or water in tank so I drained the gas and put new gas in and now it will not start at all. I've checked for fuel flowing and spark and its good. I'm so stumped. Was thinking valves maybe but not sure

[spaz12]

It very well could be your valves.
Here's Brent's video on adjusting valves:



Welcome to the forum btw!

[Fox]

Did you take the carb apart and clean the jets yet? That would be a likely suspect. Could have water in it or some dirt/grit clogging a jet.

Could be that a vacuum hose fell off somewhere or cracked or a cracke intake boot. That could cause it to sputter and die.

[drbob]

Yeah I took the carb apart and cleaned the jets, I also put on my other carb before I drained the gas and it had the same issue,would start but then want to die if given throttle. But now since I drained the fuel i can't get it to start at all with either carb.

[drbob]

I also checked the intake when switching carbs and only vaccuum line is the one from intake to petcock and its Good. Also checked petcock. Beyond stumped, my scoots been a strong runner for years, I've let it sit before for longer then a week and this is the first time it has had an issue like this. So frustrated

[Fox]

Could be electrical. CDI's do go bad sometimes and they control the spark timing.

Coils go bad.

Pickup coils go bad.

I have also seen a couple times where the leads on the coil were very loose so the spark was intermittent. Squeezing them a little so they grabbed tight fixed that. Sometimes the smallest detail is the culprit.

Only other thing I can think of is a possible burnt or warped (leaking) valve so your compression has finally dropped too low to run or worse a cracked head or piston. If you work the kick lever with your hand does it fight you strong or is it weak? A loud hissing sound on the compression stoke is a telltale sign of a leaky valve.

[scott7]

Did you check and see if fuel was going from petcock through intake line to intake?

[drbob]

Cdi and coil were next on my list before opening it up to do the valves. Kick start has same amount of compression as normal, or at least feels like it. I have an extra engine in storage, but its a true 50cc so I'd want to get a bbk. Wondering if I should go to a bigger kit this time if I go that route. I only drive to and from work 10 mins each way.

[drbob]

Update. Realised today after cleaning the carb I didn't put the drain hose with screw in it back on when fuel started to leak everywhere ( for some reason it didn't leak the other day, odd) got some starting fluid and she started right up. Not sure if the drain hose being off had anything to do with it. It's around 20 degrees today but she will start right up and run. Still stumbles some after warm up but doesn't do it all the time. Not sure why.maybe cold weather? Going to check valves after all the ice and snow is gone

[drbob]

Finally was able to mess around today. Was able to get the starter going to be able to start it. Was still getting nothing at all, was getting spark and everything but not starting. Switched out orange cdi to stock and bam, started immediately. Rubber mounting bracket thing was broken so may have been due to bouncing around. Only issue now is fixing the kickstart, ordered a new case since other busted but I think I need to replace the inner gears also. Kicks keep skipping and grinding and not working.

[Fox]