1992 CR250 2 Stroke Not Reving HELP!!! (PART 2)

check timing, swap ignition coil/wire/plug cap with a known good unit would be my next steps.

If this were my bike i would first determine if it was an electrical or carb related problem. An easy way to check for electrical problem is to use an automotive style timing light and rev the bike until it runs poorly and see if the stobe on the timing light stays consistant with its flashing or does the light cut out when the motor runs poorly. You will need to hook the light to a seperate battery for power but this is a very easy test and helps you to narrow down where to look for the problem. To check for fuel issues start the bike and then shut off the fuel and see if it starts to run better with less fuel in the carb bowl.If it does then that tells me that it is getting to much fuel so check float level, needle and seat, or jetting If none of this makes any difference start with the basics and run a compression test.Also be carful when running a two stroke low on fuel,they can really start to rev high with a lean condition so be prepared to turn the gas on or hit the kill switch if it getts out of control. If it really revs high hitting the kill switch wont shut the motor off and you will need to quickly put it in gear and kill it that way.Just dont run it very long if it does start to rev up and you should be ok.Sorry for the long paragraph I dont type much.

You said before the bike sat for a while. I've seen on 2-strokes that have sat where the crankcase gets really gummed up with old 2-stroke oil sludge and varnish. When you shut off a 2-stroke there will be a pool of gas/oil in the bottom of the crankcase. If the bike sits the gas evaporates and the oil gets really sticky. Then when you run the bike, it will start and idle but when you try to rev it the old oil sludge gets sucked up through the transfer ports and either fouls the plug or just runs like crap trying to blow all the spooge out. I watched your videos of the bike running and it sounded like other bikes I've seen with this prob before. Yours could have been even worse if the r-side crank seal was sucking tranny oil as you suspect.

Sometimes this prob will clear itself over time as fresh gas loosens the gum up and it gets burned out. Other times it will not clear up. When I have had this happen before I have had luck taking the plug out of the bike, turning the bike upside down and kicking it over a bunch of times. Lots of black drool came out the plug hole. I've seen other guys actually pull the engine, remove the cylinder, and flush the crankcase with kerosene or diesel a few times. Shake it around and dump it out.