ATC70 More Power wanted

[sstark82]

Hello guys, been a while since I posted but I just scored myself a 1985 ATC70 and would like some help.

She starts right up and purrs like a kitten, however, she hesitates a little on the low and mid range. The petcock leaks unless it is in the perfect position. I have yet to clean the carb or change the plug (which I bought all the goodies to do so). I was wanting to know if there are any tricks to get as much out of these little guys as possible. I dont wanna swap motors I would like to stay true to the 70.

I see guys roosting away on these little gems and popping wheelies but she doesnt seem to have the power needed to do it. I weigh 165lbs.

The choke position is good as well so I know it isnt that. However with the petcock leak I am wondering if the mixture may be off as well and there is too much gas getting in. 176726

Any input appreciated.

[fastatc70]

The best way to get the most out these little things is easy. Install a new motor!!!. All joking aside you can install a tb big bore kit made for the little atc. The kits are 88cc and rock and roll pretty good. The 124 cc china motors are good but you may need to install a Manuel clutch lever and a different foot peg mount. Change the coil and adapt your pull start. On the p.us side you have cdi ignition.

[Worden18]

Sounds to me like you have to start from the top. Drain the tank and remove the petcock. The gaskets are probably shot. Look at your spark plug. Is it black? Maybe it's running too rich. Rebuild the carb, make sure the float level is correct, etc. Test your ignition coil, too. Maybe it's getting weak. I had that problem on my 185 before it finally gave out. Those are the easiest things I would say that you have to start with. I'm sure others will agree.

[3wheelers]

I've got a couple ideas. First, I could clean the carb, and rebuild it if you want. A good and easy way to get power out of them, is to sand down the inside of the carb boot. (The metal tube between the carb and the head). If you look inside the boot, you will see a bunch of little bumps. If you sand down he inside and get it smooth, it adds power. A guy who used to race atc70's told me about this trick. I tried it on my 110 and I noticed a little boost in power. This is an easy way to do it without spending any money. Just an idea! Looks like a nice little atc70! Good luck!

[sstark82]

Thanks everyone for your replies. I plan on cleaning her out tomorrow and checking the coil.(didnt think about that) I will update on progress. This is why I love this site. Great guys with great ideas. Keep em coming....

[jb2wheels]

Tune up.

Points, condenser, plug. Set the points with a test light per the manual. This is the most important thing to do with the 70s.

Clean the carb (don't forget the filter behind the petcock) and tank. Fresh fuel. Clean air filter. Etc.

But the points are the thing.

[sstark82]

Well i cleaned the carb out today and was not to surprised to see it had some laquer build up inside. Soaked it good in toluene blew the jets out and also the filter behind the petcock. I also checked the air filter and there was nothing left of it cause it deteriorated over time. Just as a temp solution i had some foam lying aroumd and checked out what the filter elelments deminsions were and exactoed out a filter. Carefully drilled a hole to fit the spacer through and vwala! New filter! I also took the baffles out and ran it a while to "clean the pipe" at least thats what i said to the neighborhood. Lol i was surprised at how much lowder it got. She is running like a champ now though. I will definitely check the points next chance i get.

[sstark82]

Thanks again everybody for your input. Greatly appreciated.

[88RGuy]

$300.00 on Ebay. a 125cc lifan engine that will bolt right up to your 70.. it comes with the cdi,kicker,shifter ,carb,intake tube,,slutch cable ,throttle cable,etc,etc...everything u need to ride.. tho, u cant do this unless u are a mechanically inclined person as, some things need to be slightly adjusted or modified.. but man is it fun.. 300.00 bucks delivered right to your door.. and it is a blast to ride then...even tho u have to modify some things,, its nothing that will ruin the originallity of the 70.. its just a motor swap..

[88RGuy]

also this engine does support a 12volt system.. i.e. headlight on your 70..:) happy riding

[88RGuy]

nice lookin 70!!! great shape for an 85' !!