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it's the valves!!!!! THE VALVES!! On a hunch, I pulled the head and did a trick I read about elsewhere, shining a light through the ports and seeing if I can see light around the valve from the cylinder side. I could see light all the way around both valves, and after pulling the valves out, I saw on the exhaust valve (what seems to me) a casting defect that left a 1/8 x 1/32" hole in the valve seal.

my god.

So, the quality of this ebay big bore kit is terrible. I threw out the valves that came with it--both were thin, warped, and there's that giant casting defect in the exhaust valve. I pulled the valves from the stock head (same size, thank god) and lapped them in the big bore head, then installed them. Now there's no light visible around the valves at all. I'm going to put everything back together today, and I'll bet you a dollar it runs like a top.

BUYER BEWARE. those ebay kits may be cheap, but you'd better be prepared to lap valves and do whatever else is necessary to make them roadworthy!

It also worries me that I don't really feel resistance on the kickstarter. Back when I had a KZ750 I could stand on the kickstarter, and the compression would hold me up. I know that these smaller engines won't be able to do that, but I should feel *something*, right?? It is spinning the engine alright, however.

So the enricher doesn't put in more gas through the idle jet then, it's actually through its own outlet into the airway? Yeah, that would seem to explain the behavior pretty well. Welp, I'm not interested in taking the carb apart anymore, so I'm going to try just plunking a new carb and enricher in there and seeing what happens. This will be interesting to see.

I was pleased to see that the new carb has steel fasteners. Hopefully I've stripped my last carb screw.

Well, nuts. In attempting to pull the enricher, I stripped the brass screws holding it on. They are really on there. But maybe that's ok--couldn't we rule out the enricher just by the fact that there's a stalling problem even when it's thoroughly warmed up? Maybe the idle jet is clogged?

more potentially useful information--in attempting to get the scooter to idle, I tried moving the fuel mixture screw in and out. Screwing it in (clockwise) didn't seem to cause any change even when screwed all the way in, and screwing it out cause the motor to bog down and die around 2.5 revolutions.

aaaw, I'm back. Right back where I started, more or less. Here's the story--

Since the BBK install and ensuing hijinks, the scooter never really started very easy. That video above is the best it was, and it's been going downhill since. It got to the point where it would finally start after fifteen minutes of cranking and starter fluid, and that's where it is now.

It won't idle except very fast, and it likes to stall, even when warm. I've checked the valves, they're set at .004" intake and .005" exhaust. There's still spark, and being as it will reluctantly run, I guess there's no serious fuel issue. When it is running there's still a normal amount of power. I noticed it smoking for a few minutes once, but after turning it off and back on again I haven't seen smoke since, hot or cold. I've done the "finger test" for compression, and it feels like it always has, blowing my finger off the spark plug hole.

One more thing--it hasn't been able to kick start since the replacement at all.

My guess is maybe low compression due to incorrect piston ring gap? Would that do it? I thought I gapped the rings right, but maybe I didn't, or maybe they chipped.