I recently got a NS90ATV-t which I believe is made by Nusun ? I got it partially running with spray and eventually now on gas. Won't idle but will run if you keep giving it throttle. So, it's alive. It's a 50cc 2 stroker and has a new carb. Is there any repair type manual or wiring diagrams out there? The wiring on these is insane! I'd like to replace some components but, for example, I don't see a conventual CDI type plug in box on it. Plus, the throttle cable splits into 2 and drives the clutch also which is throwing me for a loop. Any advise, help is appreciated!

 

The throttle cable dividing into two is more likely to be connected to the oil pump and carb. Are you sure it is a 50, NS90 would indicate a 90cc engine, and a common 90cc two stroke scooter engine was used by many makers, including Polaris and Apache. These are distinctive in having an emergency kick start lever (sometimes just the spline) sticking out of the belt cover. You may find a manual and/or wiring diagram on-line. If you have fitted a new carb, it will need setting up.

 

There is a kick-start on it. I saw the NS 90 sticker on it and originally thought it was a 90 but, the only info I found was a small ad for one in dated 2006 and specs said 50cc. The motor is tiny. In new to atv's. Lawn tractors no problem, this thing is a new animal. I set the carb enough that it runs, but can't get it to idle yet. Has new gas in it. Have no clue about all the wiring yet. Bypassed the fuel valve for now and went right from the tank to get it to run. Right now it needs a shot of spray to get going but will run after that.

 

Before you do anything else you should do a compression test. Low/bad compression can give you those symptoms.

 

Will do compression test later today.

 

 

Most of these 90cc two strokes have an electric choke, you haven't mentioned if the new carb has, or if it is connected. You did mention a disconnected "fuel valve," what is that?

 

Yes, electronic choke is connected. Fuel valve is the valve controlling the main, reserve and off positions from the tank. I bypassed it to go right from the tank to carb.

 

Bypass:: you know that you would need mixxed gas/oil to do that.
Fuel valve= petcock.

 

I mixed the gas that I put in the tank just in case the oil injector wasn't working.