This thing ran far better before cleaning the carb, replacing seals, replacing a crumbling original air filter, replacing the intake manifold with one that wasn't solidified to plastic and a new OEM reed. What gives? Can only accelerate at small throttle opening.
Check to see if the "expansion chamber " is full of oil. I had a PW80 that sat for a long time, and when they tried to start it (and me too), it would barely fire, and smoke like crazy. My assumption is that the auto lube pump kept pumping oil into a dry chamber (clogged pilot jet and other carb passages clogged) until it filled up the pipe. Once I drained the oil it ran like a champ. Is the reed fully sealing? How's the spark plug look? Brown, gray, white, or? Wet or dry?
We've got an rt100 that does the same thing from time to time,even after doing all the things you've done already. 3 times now its been cheap gas from 7/11 or some other crappy place.Once we drain it and put fresh fuel from shell or sunoco,it clears up. My daughter mixes up lawnmower cans from dirtbike cans sometimes,and thats when it happens to us,when she gets in a rush to fuel up to ride. So fuel supply?
The plug is still new with only a few miles. Light brown insulator, but wet with fuel. I just checked the carb again and I think I may have found the issue, I hope so. The new aftermarket needle wasn't seating all the way because just below the clip notches it was too thick. So it was raised the equivalent of the top notch 7 of 5. That will certainly richen it up. I sanded the needle some and it's now fully seated. I'll start it up after I eat dinner.
Wow, I learn something new every day. I've never heard of someone successfully modifying a carb needle. I always wrapped them in tissue paper so they wouldn't touch each other in the box. I was going to suggest a clogged silencer, I ran into that on a DT80 once with similar symptoms.
So after going around the block with it running great, now I can't even get it to stay running. It will run for at most a second before dying. No throttle and no choke is the closest to getting it running. I've checked the pilot jet and it's not clogged. Tried a different pilot jet and that didn't make a difference.
Put a new plug in it before trying other stuff. If it ran long as rich as it seems it may have, it wouldn't take long to foul it.
Make sure it has compression... Clean the stock brass and put it back in or atleast make sure it is identical. Check the timing and make sure the points havent closed up. Those things are pretty simple...
Yeah points will be the next thing I check. Last night I kicked it over with the spark plug removed. Despite turning over a bunch there would only be one spark per kick.
Those little carbs clog at the slightest hint of dirt. Clean it again and see how it does. And install an inline filter for protection. I had a little 50 that would plug up every 20-30 minutes, no matter what I did, even with the filter (yes, cheap filter). It doesn't take much to upset the delicate fuel:air balance in those carbs.
I had the carbs off several times over the weekend, still no crud being left behind. Still seeing light through the pilot jet. No points on this, it's CDI.
Carboned shut exhaust port? Clear path from air inlet to carb mouth? Had a few little bikes carbon up to the point there was only a 1/8" hole for exhaust gases to escape. Exciter coil could be shitting itself as well. That one have reeds?
Listening to it it sounds like the air screw is all the way in or the vents are plugged up. Could be a plugged exhaust or dirt dobber nest in air intake also. If it has good compression and spark at the right time make sure air can get in and exhaust can get out.
I've got It doesn't run like the video anymore after fixing the needle. It's just not starting now after riding it around the block with it running really well. But I think I've got it figured out. I've noticed that with the bars turned to the right I get good sparks. Centered or to the left one or no sparks. Just ran it briefly with the bars to the right and it shut off once I turned them to the left. So I'm going to being checking all the wiring in the headlight housing, could be one of the wires from the ignition switch.
It was the kill switch wire. It don't remember being that way, but insulation was missing inside the headlight housing and I had wrapped electrical tape around it. That had come loose and the bare wire was making contact. I disconnected it completely and the bike is running as well as ever. Thanks for reading and giving suggestions.
