atc 70 help

[tx200m]

Hi all. Rebuilding a 1983 70 for my buddy. I have some questions. What is the torque spec for the nuts that go on the 4 long studs that hold the head and cylinder on? I have the trike running, it seems ok at idle, just has no power. When you rev it in neutral, its fine till it gets in the high rpms, it bangs out. I can put my fingers over the carb inlet and block the air flow, and it runs better. Do I need to lower the clip on the needle? Thanks for your time.

Tx200m

[Vealmonkey]

The torque spec for the "cap nuts" is 7-9 ft lbs. Make sure to use new copper washers behind them to help get the right set for the torque spec. Not sure, but usually easier to set the carb with a filter of some kind instead of wide open carb. Usually seems even more critical on the 2 strokes. Not sure if needle setting would affect the carb running but try an airfilter or stock airbox being hooked up first. Also you shouldn't be revving the engine to high right away on a fresh rebuild. Be careful, hope this helps.

[RedRider_AK]

It's running very lean. Does it run better with choke?

[tx200m]

Yes, it does run better with the choke on. Air filter is in place, still the same result. The spark plug is a little dark, not sooty. I wish I had my manual, I gave it to the guy that bought my 200 and 110.