87 Aero 50 won't start anymore

[sickelf]

My 87 Aero 50 puttered out on the way to work last week (riding it for about a year and has 7k miles). It's puttered out a couple times in the past, but cleaning the carb has always fixed it. Not this time.

The scooter just makes a pup-pup-pup sound when I try to start. It won't turn over at all. I cleaned the carb several times. Same thing. Pulled off the bystarter and plugged it with my finger. Same thing. I took off out the exhaust even. Same thing. I don't have a compression tester but I put my finger over the spare plug hole and it pushed my finger off. I pulled the plug. It seems to be dry. I grounded the plug and started. Its dark but I got a little shock and see a blue ark. I tried swapping in another plug. Same thing. I finally bought one of those chinese carbs and installed it tonight but it does same thing. I tried pouring a little gas into the spark plug hole to see if it would start, but all I hear is the pup-pup-pup sound.

Anyone have an idea of what to try next? My dad said it could be the head gasket. It did seem to be running a little rough recently. It was idling out alot and the engine just sounded rougher than it used too.

Thanks for any help.

[patthesoundguy]

Pull the head and inspect the condition of the cylinder and piston, its likely toast. If it doesn't sound right it probably isn't right with out a compression tester and with out pulling the head you will just trouble shoot in circles. And spark plugs can spark outside the cylinder and not fire when installed. Did you check all of the intake system, air filter element, airbox and the connections. Maybe it went lean and killed it. I find if a two stroke starts to run rough you are on borrowed time usually, because something has changed to cause the rough running.

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[sickelf]

Yes I checked intake and airbox. I'll pull the head this weekend.

[treekiller]

Remember the holy trinity whenever diagnosing a No start condition.
Fuel
Compression
Spark

First fuel.. (starting fluid is best to test this) squirt a bit in the airbox, if it starts, you know your problem is fuel related.

second Compression, Thumb over the hole is one test, but an auto parts store will loan out a compression tester for nothing. Many argue on what engine should have what Number, but typically anything over 80 PSI will start. even if it does not run exactly well.

Third spark, Ground out the plug AND CRANK, should have a nice hot blue spark, even kicking it over.

Fuel could also be a leaky case seal, or a failed reed valve. Reed valve you'll feel air blowing back out the carb when cranking. case seal is harder to diagnose. (I built a leakdown test fitting that goes in place of the oil pump that can compress air into the case) you'll be amazed how many scoots are running around running like crap. with leaky cases. even mine until all my parts arrived.

But I always leave tearing down the motor till after all these items are checked. Don't forget Honda Vacuum petcocks love to stick in the shut position, a lot of times once I start the engine on Starting fluid THEN it will generate enough vacuum to yank open the petcock, and the scoot will be fine.

JL

[swimmingfree]

starting fluid it will strip out the oil and may fry the jug!!!!!
I USE GAS OIL MIX DOWN THE SPARK PLUG HALE NOT STARTING FLUID....
swimmingfree