New carb - still not running

[cardinalsfan]

Hey everyone, back from my Hawaii vacation and weather has cleared up here so I'm back to working on my scoot (details below in my sig).

Last I left it I was having problems getting it to start - I can eventually start it but I have to keep it at 3k rpms for it to continue running.  Any lower and it sputters and dies.  

I plan to check my valve clearance today after work and set it to .004.  I also plan to change out the gasket between the carb and the block.  

All of this is happening with a brand new verified keikin 20mm carb.  Bought from a certified seller that was recommended here on the boards.  It was running fine on the stock carb.  I did find that the tube that connects the air filter housing to the carb inlet was busted but I fixed that with some epoxy and now it's sealed again.  

Any thoughts on where I should start with carb tuning to get it to run or is it some other issue?  

[niz76]

Carb tuning is basically getting the air/fuel mix correct, so you can do little things like cover your airbox with your hands a bit to restrict air intake (making the mix richer) and see if that makes it runs better or worse. You can also remove a couple screws from the airbox cover and crack it open a bit to let more air flow in (making the mix leaner) and see if that helps or hurts...

Once you figure out if you need to go richer or leaner, you're off and running and time to order some jets!

[oakleyscoot]

Check for air leaks on engine side of carb.
sealing on intake to carb and seal intake to head.

It is possible that the mixture is lean because of air coming in after the carb.


My .02¢

[FrankenMech]

Checking compression etc is first. Getting the idle jet and throttle set right is the next thing. Once it will idle properly then you can start working on the main jet mix.