So I finally got my quad running. 2008 TaoTao 125cc used that I bought off craigslist. Engine runs great now, but when I take the brake off and push the gas, it just bogs down and dies. If I hold the rear tires off the ground and push the gas, the quad runs like a crazed banshee. I have no freakin clue where to go from here. Please help!!!

 

Believe it or not having the wheels off the ground makes a huge difference in the actual "load" on the engine. I would start first by making the main jet richer to get more fuel in the combustion chamber. If that does not do it, you need to check compression.

 

Hello ;

I would start with doing a few things - first off I would remove the carb and give that an impressive cleaning making sure you can see through all pilot holes in every jet - I would then reinstall the carb and begin to adjust the carb with the air/fuel mix screw get the quad fired up and turn that screw closed until it dies - then turn it back out 2 turns and fire it up - keep adjusting this screw outward until you have a heavy idle - then move to the idle screw and turn that out until the thing is trying to take off on it's own then turn that inward until it's stopped by bouncing kinda trying to jump foward but not quit..

hold the break and jam the gas all the way open (does it rev out or does it choke and die?)

 

thanks or the ideas. the carb is brand new, but i guess it couldn't hurt to pull it apart and clean it again anyway. I have both screws in all the way. If I try to back them out (to the left) the quad dies. I did raise the needle with the e-clip, but no dice. I locked the front brake, but when I push the gas, it dies. I bought a compression tester, but of course the adapter is too big to fit the spark plug hole. Any idea where I could find the correct adapter? If anybody has any other ideas, feel free to share, as this whole situation is very frustrating.

 

your cam timing could be off a tooth, mine came that way stock (I bought it new). Once I fixed that it ran much better.

Also, your carb is probably too lean if it is stock. I took my jets to the local cycle shop and they couldnt match them up.. I ended up drilling them out myself with a micro drill bit set.

The last thing is the stock gearing is way too high. Get the largest rear sprocket you can find or it will die when you try and climb hills.

If you search for posts I have been in there was a long one where me and 2 other guys worked this out and there are some usefull pics in it.

I addressed all 3 of these issues and got my sons quad running pretty darn good. The torque still isnt that good, but its good enough for a child now. When I bought it it was basically unrideable (liek yours), and it was a xmas present. It took me a couple months to work out all the bugs.

If you can't find the posts I referanced, pm me and I will see if I can dig up the pics.

good luck

 

could be bad valves