Has never started

[ImpulseRocket]

get rid of that auto choke carb for now and put the original one back on. Make sure the needle has the clip in the middle for now. As others have suggested, get an NGK plug. The ones that come with these kits are generally very poor and often bad out of the box. Even though you can create a spark in open air, it may be unable to spark under compression - known as blow-out.

A unique problem with that particular cylinder design (CDH LD100) is that the intake flange has VERY thin flanges at the corners of the rectangular intake port, and it is very well known to leak. There just isn't enough flange surface there.

 

[Amwicr]

Got this “100cc” engine kit on Amazon. Completed build and couldn’t get it to start. Carb that came with the kit was damaged when I got it so I installed the one shown above with auto choke. That did not fix the problem. Looking for any advice on what to try. I am new to motors and new to this forum. Here’s what I’ve done so far: Ensure fuel ratio 16:1, check for good spark, check throttle working, messed with idle adjuster, gapped magneto loop, checked direction of magnet, tried riding at various speeds and combinations of choke / throttle. When I try to start it I don’t even hear a single pop. Don’t have the air filter on. Any ideas what I could be missing?

Can you hear the engine turning over? Is the clutch working properly?

 

[roadbike]

Can you hear the engine turning over? Is the clutch working properly?

Yes and yes

 

[Amwicr]

#1- put brand new fuel in (20:1), drain the bowl of old fuel.

And even if the fuel isn't old, the thing might be flooded, so emptying the carb bowl is definitely a good idea