ATC 70 running weird

[hummbusa]

I can't for the life of me to get this thing running good. So far I have taken apart and cleaned the carb completely 5 or 6 times. Flushed the gas tank. Put in new points and condenser. New sprockets and chain. I can get it to start and idle fine but when I rev it up just sitting there it don't seem to rev past maybe half way to where I think it should. Same thing when I drive it. It will run through all the gears but just won't rap out. My trx70 just flat smokes it....it's almost faster to walk next to it anyone have any ideas. I'm also having a real hard time setting the timing...I move it one way or the other and get it running so I figure I must be close on the the timing...help me please I want to ride this little thing around. Thanks

[Bucktorious]

make sure the ground wire has a good connection. It might be a little loose, and when the motor vibrates it loses contact with the frame.

[Hair Bear Bunch]

Thinking outside the box here, but is the throttle lever limit bolt stopping the full movement of the lever at the handlebar end?

[muthey]

Also another thing to look at there is a w clip on the throttle body which holds the needle in place, check to make sure it is there, or it will push your needle up causing throttle issues. Also have you checked the air filter, and or sprayed carb cleaner aoround the intake boots checking for air leaks?

[hummbusa]

"make sure the ground wire has a good connection. It might be a little loose, and when the motor vibrates it loses contact with the frame. "
Checked and double checked

"Thinking outside the box here, but is the throttle lever limit bolt stopping the full movement of the lever at the handlebar end?"
Just removed it but it has been replaced with a short one so it don't interfere at all

"Also another thing to look at there is a w clip on the throttle body which holds the needle in place, check to make sure it is there, or it will push your needle up causing throttle issues. Also have you checked the air filter, and or sprayed carb cleaner aoround the intake boots checking for air leaks?"
Brand new air filter no idle change when sprayed around while running.
The needle does have the clip because I have moved it up and down trying to get better results....But I just set it back in the top of the carb and screw the top on. Is there something it clips into? I thought I had it right because if I dont turn the cylinder the right way it wont screw on or it make it so it wont allow the thumb throttle to move full motion.

I have it running and it idles fine but when I rev it up it goes up maybe a 1000-1500 more rpm's...just guessing but it dont sound like its eveen pushing the engine (hence afraid its going to blow). I just got done riding it around the lot went through all gears but moves ever so slowly. It did stall once so I bump started it and off it goes again. I'm starting it with a drill if that matters just because I dont want to assemble it till its running right.
Thanks so much for the suggestions so far!!!

[R-tifacts]

Petcock choked with rust ? I have had nothing but trouble with the points on mine, if they are not set up perfect, and clean they will run like a bag.

[Hair Bear Bunch]

How old is the fuel?
I think I'd be inclined remove the whole carb, carefully and gently dismantle it so if there is something blocking the jet you don't dislodge it 'till you find it. I've had it where the jet looks clean but the crud blocking it only gummed it up when it was running, absolutely infuriating. Check the filter screen behind the petrol tap, then go to the manual and set the carb up as per the book - idle screw, jet screw and the needle clip setting ect. and start from scratch.
I'm not familiar with the geography of the U.S. so I don't know too much about Iowa, but there can be needle clip issues above certain altitudes, again, the manual should help.
If all else fails, could you swap the carb from the TRX? That would prove the timing, then put the the ATC carb on the TRX to set it up perhaps? Either way around it should define the problem to one area.
Rob.

[shortline10]

Are you using the stock air box set up ? Aftermarket open air filters dont work on stock atc70 carbs . Try running with the choke on and see if it will rev up . If the points are old replace them even if they look good , it will make a big difference and a much better spark .

[muthey]

there are two clips that hold the main needle down, reading what you responded and I may have read it wrong, but there is the positioning clip, and then a w clip which fully holds the needle into the throttle valve see detail 2 on pic

brandon

[hummbusa]

Thanks for all the suggestions!! I will work on each one tomorrow when I'm back at my shop.
The fuel is brand new and looks clean.
I did take the carb back apart and it did have some gunk (rust) I think so I cleaned that again.
I took the tank off and emptied it and it was pretty gross. I filled it with water numerous time and shook it out till it was running out clean water only.
I put it all back together and got it fired up but it only ran for 5-10 seconds then it would not start again...my drill also ran out of juice...
My questions are the smaller jet without the nut on it seems almost like it has 5 small holes in it when I look through it into the light.
Also I'm going to put a couple of in line fuel filters on the fuel lines.
I may have to reset the gap on the new points but man it seems so hard. Any good or easy way to do it...I'm sure I'm not the only one who has problems on this little 70 setting the timing...they are new points if that makes it easier.

[hummbusa]

there are two clips that hold the main needle down, reading what you responded and I may have read it wrong, but there is the positioning clip, and then a w clip which fully holds the needle into the throttle valve see detail 2 on pic

brandon

I don't really see the two clips in the diagram?

[hoosierlogger]

I think the 2 clips muthey was talking about is the E clip on the needle and the W shaped piece that goes under the spring that holds the needle firmly to the slide.

[muthey]

correct Hoosier, not to say hummbusa doesn't have it assembled right, but there is a chance that it is not there, if he has moved the clip on the needle and doesn't know what the w shaped retaining clip is. Even if it is there it is always good to double check cause I have had them move on their own before, still don't understand how and why they did it but they can.

[hummbusa]

OK that "w" clip was not holding down the needle...duh I feel stupid. So I adjusted that correctly. I also ran up to the local small engine repair shop and got some yellow/clear gas line and 2 in line filters. I used my compressed air and blew out the tank and the two outlets running out the bottom of the tank. Yesterday when I was cleaning out the tank the bottom outlets did not seem like they just flowed out a lot of fluid so I took extra care and blew them out really well...so I thought. I got everything put back together and tried to get her started but no luck! Also I can see the gas in the lines and filters and it just don't have hardly any gas to speak of. I would have though by turning the petcock on and pumping the throttle or turning the engine over with the drill it would have drawn gas through the lines? I am stuck and it don't make sense to me!!
I also tried removing the gas cap thinking maybe a venting problem.

[oneroom42]

i have delt with this before. points are wrong. trust me!!