Ok folks, need some help with my 2000 honda 400ex.

My quad is fully stock, except a K&N air filter, white brothers e series exhaust, white brothers header.

I have never changed the jets or have taken the carb off this quad. The numbers are as follows. Main jet is 158, small jet is 38.


I rode this quad with the pipe and header on it for 3 years and never had a problem. I let it sit, and today decided to get it running in time for snow. My buddy and I removed the carb, fully cleaned it, and removed the jets. The small jet was plugged with gunk, so we used a micro drill bit to get the grime out. The main jet was perfectly fine.

After putting it back to together, we started it up, seemed weird sounding. We think it is running way to fat. During Idle it chokes it self out, but in first gear, when u jam the throttle or slowly push it, it Boggs down, zero power.

We played around with the pet knock, and when it is literally in the off position the engine becomes alive and sounds perfect while in neutral. It doesn't bog.

Also, looking at schematics, we noticed a hex nut that is installed with the main jet. We didn't see one?? Is that needed? Is that our problem


Am I running too rich?

Also, I replaced the spark plug and air filter is perfect and fresh gas as well

Suggestions on the jet sizes and fuel mixture screw ?

I greatly appreciate all help for a carb newb!!

 

The small jet is called the pilot, and is responsible for idle to about 1/8th throttle buy itself. First I am thinking you may have accidentally made it a larger jet with the drill. A quick and fairly cheap solution is to just buy another 38 pilot. It looks like that nut goes to the needle jet assembly, which takes over from the pilot. yup, probably needed that, did it have one when you took it apart?

I usually just use a solvent and/or compressed air to clean out the jets if they are clogged.