eastsideTim said:
Replacement CDI and Coil did not do the trick. Pulled the plug and checked it, too. I pulled the cam cover, and checked valve clearances. Intake was fine, exhaust was on the low side, but still should be good. Pulled the carb again, rechecked the idle and main jets, and backed out the idle air screw. I've hit the point where I can get it to start after a hit of starter fluid, and fast idle, but when I try to adjust the idle speed down, it bogs and dies. Been doing this all by ear, so it's possible I'm trying to get it to idle too slow, but since it doesn't want to start without starter fluid, I doubt it.
In doing some searching, in at least one case, someone was having idle problems, and replaced the stator, and that fixed their problem. Seems an odd fix. Debating tearing into my rebuilt engine to grab the stator off it, but not really motivated to do that right now.
Don't know how I missed this thread over the years. I want a pit bike/something for me to do stupid stuff on. I would have bought that mini bike from you.
In reply to Stampie :
I'll let you know if I decide to involve myself in any more stupid ideas, and then divest myself of them. 
Carkid has dibs on the Buddy right now, but if I decide to swap my spare Buddy engine into the Elite E, I may have a total rat of a Honda Spree to get rid of.
It's not the stator, either. Had a thought as I was about to wrap up, that maybe the intake manifold was cracked and there's a vacuum leak. Didn't see anything visible, got the bike running again, and sprayed some brake cleaner around it. Thought I heard a bit of a surge at one point, but it is possible it was just the way the bike is running. Since it is getting a bit of popping when I give it throttle, maybe the bottom of the intake is cracked and letting air in, and the bike is going lean then. Couldn't pull it apart tonight while it was hot, so I'll wait until tomorrow or the weekend to check out that theory. After that, though, I'm out of ideas, other than throwing it up for sale cheap just to get rid of it.
Pulled the intake manifold this morning. Looks good to me. A little gasoline in the manifold and in the head. Making me wonder if I am chasing the wrong thing, and it is too rich. However, if it were so rich it wouldn't idle, I'm pretty sure I'd be seeing exhaust smoke and smelling a lot of unburnt gas when I have it running.
Maybe I'll get out the multimeter and start checking wiring for high levels of resistance. Or maybe it is time to give up, since I have other projects to work on.
The troublesome engine is the 125CC Buddy, right? You mention changing the oil, so I'm assuming it's a 4 stroke. Any chance the woodruff key sheared and the timing is all out of whack? These mystery conditions you describe remind me of countless 2-stroke issues where the key on the crank gets sheared in half and every other component on the engine is correct except it won't run or won't run well because the timing pickup is just in the wrong place for the engine.
In reply to Mezzanine :
This one is a 150cc, but basically the same, improved version of the GY6 design. Timing should be good, the key was in perfect shape when I swapped the stator out. From the looks of it, I'm probably the first person to have the engine apart this far. Not too surprising, since I think it only had somewhere between 4-5K miles on it when I did the swap. It might still not hurt to throw a timing light on it. I haven't reinstalled the cooling ducts yet, so I could pull the cam cover again, find TDC, and mark it on the flywheel. I'd still be running somewhere around 3000 RPM would be my guess, but if it is really out of whack, maybe I'd notice. That was part of the reason I swapped the CDI, figured there was always a chance it was failing and screwing with timing. May be time to make sure I was right on the valve clearance, too. 0.004" fit under the intake just fine, and was snug under the exhaust, so I figured even if it could benefit from an adjustment, it didn't need it yet.
I may also cap the vac line to the petcock, and see if I can start it up with just the fuel in the carb bowl. Just to make sure I'm not flooding it somehow.
Tests this morning:
Tried running with no vacuum line to the petcock - no dice
Checked compression. Its 120 psi cold. A little on the low side, but still should not be having this problem. Was also using the rubber stopper on the compression tester, since it did not include a threaded adapter of the right size.
Checked continuity for the coil wires. Ground was fine. Positive to the CDI was fine. Both showed between 0-0.3 Ohms of resistance, so that does not seem to be the problem.
I pretty much have nothing. If I really want to get serious, I have a intake manifold riser that I could use with the brand new GY6 carb I bought a ways back, but it would not be a permanent solution, only a way to confirm or eliminate the other carbs as the problem. I suppose timing could be out, so I could pull the cam cover yet again to find TDC, and give that a shot, but none of that is adjustable, so there's be nothing I could do to fix that, as far as I know.
Stampie - if you are looking for something two wheeled to mess with, this may be showing up in the for sale forum soon. However, I'll be selling it to whoever can come get it out of my sight fastest.
Tossed the timing light on, and started swapping CDIs. Lowest I could get it to consistently idle was about 2800-3000 RPM (5600-6000 on the timing light tach, wasted spark system). If I tried to adjust the idle down any lower, it'd start to stumble, then die. Sometimes a quick rev, and tightening the idle screw could get it back up to speed, sometimes it didn't.
