(Not scooter) Engine runs horribly, help

[utp9]

SOLVED!
www.reddit.com/r/MechanicAdvice/comments/8rie9q/please_read_any_help_is_appreciated_engine_is/?utm_source=reddit-android

Hello everyone, please go through the post and if you have ANY advice please feel free to give. On mobile.

I just installed a big bore kit 50cc to 75cc. Only other thing I changed is in my 16mm PHBN Dellorto carburator I replaced the 110 to a 138 jet and went from 1.5% premix to 2-2.5% (manual states 1.5% for synthetic and 3.0% for mineral, so I don't believe too much oil is the issue.) I started the engine, but you could tell it was too rich.

After some riding this happened: youtu.be/zRAw7uffxtQ I changed to a 128 jet, which slightly improved it, but not greatly. I pulled out the spark plug: imgur.com/gallery/WKGOZE7 It seemed to be oil fouled. So, I put a new one in and it worked for awhile perfectly.

After a bit more of riding this happened: youtu.be/VqW-ZmgnxjA It will not run on anything except full throttle and it randomly starts working normally.

Currently, the plug looks like this: imgur.com/gallery/1TDJGMY I tried putting a 110 with no air filter, didn't help. So, I do not understand if it's too rich/lean.

Lastly, there seems to be a back liquid (oil)? Accumulating near the exhaust port and near the spark plug as it was slightly loose: youtu.be/QCTqA6EiH0Q

Now, it doesn't start at all, I believe the plug was fouled again.

If you have any idea how do I fix this PLEASE comment any ideas, thanks!

EDIT: Seemed to be just a too large jet, now I put a fresh spark plug and the 110 everything seems to run fine. Thanks everyone!

Previous posts:

www.reddit.com/r/MechanicAdvice/comments/8radbd/how_come_it_bogs_and_dies_after_giving_gas/?utm_source=reddit-android

www.reddit.com/r/MechanicAdvice/comments/8re19w/how_do_i_fix_this/?utm_source=reddit-android

[2stroked]

It would help tons if you were to type out your issues here as well. That link didn't work for me from mobile. Just a heads up.

[jackrides]

More engine details needed. It's obvious there is too much oil or gas in the mixture. If you did nothing to increase he oil to engine flow, there is too much fuel. Back off the fuel jet numbers and see what happens. Does your carb have a drain line to the float bowl?

[utp9]

Jun 17, 2018 1:14:09 GMT -5 jackrides said:

More engine details needed. It's obvious there is too much oil or gas in the mixture. If you did nothing to increase he oil to engine flow, there is too much fuel. Back off the fuel jet numbers and see what happens. Does your carb have a drain line to the float bowl?

Yeah, I just had a too large jet size, thanks.

[ThaiGyro]

It would help to know if your entire system was clean...intake, filter inside air box? (pod?) Ignition timing OK? spark advance/retard working? Most important...is your exhaust pipe clean and have fresh packing?

The answer could be in one of those.