What makes a carb go bad?

[GIJoeBob]

I have an ATC70 I am restoring for my daughter and I can't get it to run. I have traced the problem to the carb. The motor is stock as is the carb.

I ran the carb through a carb cleaner dip and put new O-rings and gaskets on it. I have ran carb cleaner through all the holes several times and blown out all the holes with compressed air as well. I can't find any obstructions but the thing still won't run.

The bike turns over and pops when starter fluid is shot down the intake and I know I am getting a good spark.

So my question is - what can make a carb go so bad that it can't be cleaned to work right?

[Liquid-Darkness]

Carbs that come from running bikes usually don't break. Either some nut has crammed the wrong jets and needle into it, or its working parts get worn. That or plugged holes ect. Usually a complete carb rebuild kit and the right settings makes almost any carb come back to life. If the carb is getting fuel and is rebuilt and set up right, then the problem is not the carb. This kit below should fix any carb problem. When my old 200x wouldn't idle I thought I would never get it fixed. The carb had been taken apart and blown out many times and it still wouldn't idle. I bought one of these kits and rebuilt it. WHAM the bike fired and idled. Sometimes they just need a rebuild. Good luck.

http://cgi.ebay.com/ebaymotors/HONDA-ATC-70-BEST-CARBURETOR-REBUILD-KIT-ATC70-CARB_W0QQcmdZViewItemQQ_trksidZp1638Q2em118QQcateg oryZ43979QQihZ020QQitemZ300182528277QQrdZ1QQsspage nameZWD1V

[GIJoeBob]

Strange, those O-rings are not the right shape for my carb. This one looks like mine-

http://cgi.ebay.com/ebaymotors/NEW-BCIs-ATC70-ATC-70-CARB-KIT-SAVE-A-CARB-CARBURETOR_W0QQcmdZViewItemQQcategoryZ43979QQihZ00 7QQitemZ170180219471

[Liquid-Darkness]

Yeah that pic is just for reference. It supose to come with all parts to rebuild an atc 70 carb. The kit you show looks better but they both do the same thing. Your kit probably comes with more parts. Either kit will give you new gaskets, orings, needle set, jets, idle screw, mix screw springs and float valve. The throttle slide valve, I am not sure about the kit I mentioned. Shoot if you can the kit you posted would be ideal. Then you just gotta adjust everything on it right. Go for it dude.:beer

[3Wheelers4Life]

is the engine getting fuel? pull the engine over a few times, and take out the plug is it wet with fuel?

[rally4x4racer]

right - that was my first thought. is your petcock plugged? are you running a filter?

[GIJoeBob]

right - that was my first thought. is your petcock plugged? are you running a filter?

So far the only gas being sent to the carb is out of a K&L fuel bottle so I know it's clean and it makes it into the bowl because I have to drain it to get the carb off.

I want to say that the spark plug had fuel on it when I pulled it but I was working on two bikes at once so I may be thinking of the other one. I'll check again today.

[rally4x4racer]

you are on the right track then...

Next time you have to take the carb off get a flashlight and look down into all the ports and passages - see if you find something.

[GIJoeBob]

I bought and installed a carb rebuild kit and got the thing running more or less. After it sputtered for a while and I fiddled with the carb settings I decided to change the oil. That is when I mistakenly removed the bolt holding the cam tensioner in place and the springs and rod plopped out onto the shop floor. :(

I reinstalled the parts in the proper order, changed the oil successfully and now the thing won't run. I am wondering if just by removing the tensioner the timing could have been changed.

Any thoughts? Thanks for your help.

[GIJoeBob]

I bought and installed a carb rebuild kit and got the thing running more or less. After it sputtered for a while and I fiddled with the carb settings I decided to change the oil. That is when I mistakenly removed the bolt holding the cam tensioner in place and the springs and rod plopped out onto the shop floor. :(

I reinstalled the parts in the proper order, changed the oil successfully and now the thing won't run. I am wondering if just by removing the tensioner the timing could have been changed.

Any thoughts? Thanks for your help.

Turns out the key on the magneto rotor was worn off. One trip to Lowes and some work with the Dremel tool fixed that issue. I put it all back together and it's running!

[Bryan Raffa]

good deal ..good to hear you found that..so its running good now?
your probley out rideing it.........:) now is it really the kids or yours?:lol: :welcome:

[GIJoeBob]

good deal ..good to hear you found that..so its running good now?
your probley out rideing it.........:) now is it really the kids or yours?:lol: :welcome:

It's running but certainly not running well. The carb needs adjusting and it needs a new copper seal for the exhaust at least.

I have all the fenders for it but I think I will be ordering the pink plastics from Dr. ATV and painting the rest of it as well since this one will be for my daughter.