I've bought an 07 Sunl 110, 107cc actual. Model 7sunx 110ACX.

It was not running and this original owner thought it was carb. I tried starting it just to see and it just cranked and cranked.

So, here's what I replaced:

1. spark plug (ngk c7hsa)
2. new fuel
3. carb
4. cdi
5. coil
6. regulator

Still wouldn't fire but had spark. Tried adding a half a strawful of gas to engine. After cranking a bit, it started but maybe one revolution of the engine then nothing. Cranking with choke on/off, checking all the safety devices, etc. All I could get was just a pop of the engine - no significant running engine time.

Adjusted the valves to 0.004 intake and exhaust*. Replaced the plug. Got it to fire up with no strawful of fuel, just lightly pumping the throttle a couple times and choke on. Longest it ran was about 5-8 seconds with a couple 1-2 second run times till the battery died from cranking.

Looking for advice on what to do now. Is this still a valve issue or a carb issue? The fuel line and filter looked new, but I know how that goes. However, I had good flow from fuel line when removed from carb.

* I'm not sure I had the correct marks lined up on the fly wheel. I have another post on this. I watched the youtube video on adjusting chinese atv valves. I watched for the intake valve to reach the highest point then found the closest mark on the flywheel. With the lock nut loose, I was able to hand turn the adjustment bolt so this made me feel like I was doing this correctly. But it was the same mark on the flywheel for both intake and exhaust which seemed odd to me that would be the case since you'd think one would open and the other would be shut but I am not sure. Both valves appeared to be at the highest point at the same time. Bottom line is that the atv went from NOT running to RUNNING - albeit with another new plug but the valves had to be a big reason it started.

 

Without any further changes, got it started and running but won't hold idle and have to keep pumping gas. Seems to be running really rough. Rough = bogging mostly trying to keep it running by staying on the gas. Have rear wheels in air spinning. Cranks for long time to start. Any ideas?

 

and you did say you replaced your carb, right? as this is symptoms of a clogged pilot jet and/or incorrect fuel mixture screw setting.

 

This may sound odd but it worked for me many times...take the gas cap off and while your cranking blow into the tank to pressurize it. It's crazy how good it works if it's a clog.

 

The carb is new but I'm going to take it apart to clean then adjust
Following this forum. I also don't like how they got the fuel line run. Reminds me of a p-trap without that severe of a bend but it drops down and comes back up, then down to carb. Has filter on fuel line. Again, get good flow from fuel line when unplugged from carb but will also try blowing into tank. Will report back.

 

I bought my daughter an off brand 50 just to see how she liked and it needed a carb. I don't know what kind of carb you put on it but in my experience the $25 carbs don't work they way they are supposed to. I bought one still wouldn't start so I put a mikuni carb on it and have not had a single issue it actually suprises me how well it runs with a quality carb on it. But yeah get a tight seal around the tank lid hole and get some pressure in it and see if you can force it through I actually did that the other day to another quad I was having tribe with and it fired right up

 

FYI, "if" it is a clogged pilot jet, blowing in the gas tank is not going to clear it out.

 

Unless you get a carb from the bike maker, it is not going to be set up for your machine. As it usually takes longer to set the new carb up than it would to clean the old one out properly, I never fit new carbs unless the old one has had a broken casting.

 

Merryman, good advice. I got four carbs from the seller. 2 were old and 2 new. One still in plastic. That's the one I used. All four identical. Replacements came from sunlpartsonline. However, I agree that looking for the original out of the two that are used and cleaning it may be a better option at this point. Haven't had a chance to mess with the quad this week anymore but will repost once I get back into it Saturday.

 

90% of these quads run a vm19 style carb that is made by mikuni .. There are many knock off company's that have copied this carb with cheaper more inferior metals and very poor crafted jets. So really your replacing the Chinese copy of your carb with the original higher quality carb. And the cast is essentially identical.