OK, so I added a new 30mm carb to a 150cc.
It is a PZ30.
The problem is when running it has rough idle and when I throttle up gas sprays out of the carb throat towards the rear of the bike.
Is it possible to have too much carb/jet?
The gas is coming from the main jet as the needle connected to the cable begins to slide upwards to allow more fuel and air in.

Answers? I'm stumped on this one.

PS. Bike runs hard at full throttle like it should, just continues to spray gas outwards.

 

I am thinking the carb problem is that this bike has a 22mm intake and a 30mm carb. I think the gas is slapping off of the intake spacer, but am unsure.

My newest problem is today for no apparent reason I lost spark. I took some readings with the volt meter but they are all over the place. This 150cc has the GY6, but a 6 wire CDI. The CDI has a 2 wire plug with a Black/white wire and a Black/red wire. The other plug has 2 green wires, a blue/white wire, and a yellow/black wires. The yellow/black wire goes to the power side of the coil. This wire has voltage jumping everywhere from .5v~30v. The black/red wire has 30v on the cranking.

Shouldn't these voltages be higher?
This plug configuration is also very square VS. the rounded 5 wire plugs. I ordered a CDI but did not unplug the original and ordered the 5 wire. I needed to look a little harder and next time assume nothing is standard about these bikes.

 

BTW, the bike is a 2008 150cc Tao Tao Sport ATV.

 

Update:
I can not get the PZ-30 carb to work right. It idles great, but no mid-range and no WOT. It blows gas outward when this happens. I tried 2 carbs and the problem happened on both carbs.

My train of thought was that the intake valves were out of adjustment but they are not. So the newest idea is to change the intake pipe to a 30mm tube and then use a different brand of carburetor at 30mm. I want the bigger carb to get the most out this 150cc.

The spark amazingly returned like it never left. I am still confused what happened there. Hopefully I have this quad running by next weekend. Will update again soon.

 

Somehow I missed this post from a long time ago. I wasn't ignoring this post - I just missed it somehow.

I've never measured a "square" 6 pin CDI but am assuming it is the same as the rounded two connector CDI inside except for the connectors. You said you ordered a 5 wire CDI? Is this the standard 5 wire 1 connector version? If so, I don't know why you did this unless it was a mistake - but having taken apart the 5 wire CDI and the 2 connector 6 wire *AC powered* CDI I can tell you with certainty that they are exactly the same inside except for the connectors. It will work, but you will have to wire around the connector mismatch.

To those that are coming here through search engines: Note that the 2 connector 6 pin CDI's come in DC powered and AC powered versions. They look identical. This post only applies to AC powered 2 connector 6 pin CDI's.

30 volts is low for the AC power on the black red wire. I get 80 volts AC while cranking on mine. Did you make this measurement while the CDI was disconnected? The CDI yanks this voltage around even when things are working normally so when you are having problems you want to measure the stator power output AC voltage when the CDI is unplugged.

I've never seen as low as 30 volts AC on a GY6 quad (CDI disconnected) while cranking on the black/red wire. I've had others report that 35 volts AC on a 110cc quad works (5 wire CDI - but remember that the 5 wire CDI is the same as the AC powered 2 connecto 6 pin CDI). Maybe 30 volts is OK. I don't know where the lower threshold is.

The voltage to the ignition coil is very narrow very high frequency pulses. Your meter isn't designed to measure this type of voltage waveform, so what you usually get is mostly zero volts with random AC voltages interspersed when the meter happens to sample while this AC voltage spike is happening. It may capture some or all of it, hence the varying voltages. And different meter designs measure these pulses differently. This isn't ideal - but we have to use what we have.

Let's hope your spark continues to work. If it fails again then we can look into it.

 

On these chinese bikes their is a certain amount of vacuum required for the venturi on the carbs to work right. I gutted the factory air box that had a 7" air tube, this restriction may of been what the carb needed to build enough vacuum pressure to work right.

That is why I am changing intake and carb design. I will keep you posted on that front.
When I get time I will take another voltage reading, maybe this weekend. I will see what it gets with a hot spark.

I ordered the performance parts assuming that they were pretty typical of a 150cc GY6 motor. Not so, I will not make that mistake again. Shame on me for assuming anything! LOL