81 Atc200

[Yammerhead]

OK, my friend gave me an ATC200 that wasn't really running very well. I tore it down and put a 1.5mm oversized piston in, ground the valve seats, put in new valves and slapped her back together. Didn't want to start. So I checked for spark, which seemed to me to be very weak. I put in a new source coil, then a new CDI, and finally a new hi tension coil, sparkplug cap and plug. Little better spark now, but still not as good as I expected. If I pull it over with the sparkplug body grounded to the engine block, you really have to look hard to see the spark. I bought one of those spark testers and it sparks much better when using the tester, so I am assuming I have sufficient spark. I got it to run for a short while, but it would not idle and eventually died. Now it only fires once in a while and won't run for much more than a second or two. Choke doesn't help. If I give it a little shot of starting fluid, it will usually fire but then stops. I have cleaned the carb three times, all of the passages are clear. The needle and seat hold pressure. When I pull it over with my hand over the carb, there is good suction and my hand gets wet from gas. There is 140PSI compression on my cheap guage. I did a leakdown test and it is less than 15%. The timing has been checked with the valves both being closed at "T" on the flywheel. The timing marks on the rotor and pulse coil are lined up when the mark on the case lines up with the "F" on the flywheel.


Any ideas on what the heck could be wrong??? It is acting pretty much like it did when I first got it. Makes me think there is still something fundamentally wrong that I haven't addressed yet.


Help!!!!!:confused: :confused: :confused:

[Yammerhead]

Well, good news. After just about giving myself a stoke trying to figure out the problem, I found it. The new spark plug cap I bought was a 5K resistor type. Big mistake. I bought a new non resistor type and the thing fired up on the first pull!!:w00t: :w00t: :w00t: Adjusted the carb and she purrs like a kitten.


Now, I took it out for a short rip and it pulls good in 1st and second but when you give her gas in third, it feels like the clutch is slipping. I have never had the clutches apart on one of these things, but from what I read, you adjust something by turning the slotted bolt on the right side of the case in until it bottoms out and then back it out a 1/4 turn and tighten the nut. Is this correct? What does this slotted bolt adjust???

[erectordale]

IT adjusts the clutch pressure on the clutch discs