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Timing question

Posted: Tue Nov 26, 2019 2:36 pm
by Jodaddy
88 elite sb50. Has spark fuel and 120psi at wot. Tired of kicking. Pulled the flywheel and the key was in place. Bummer. Hooked up my timing and cranked the motor. Timing light flashes on the pickup and not the “f”. Seems like it’s 180 out. Is that possible or is the cdi just busted? Thanks. Joe

Re: Timing question

Posted: Tue Nov 26, 2019 5:20 pm
by bonesv
How could timing be out? There’s a lack of info to go on. Did you just acquire this scooter? Give us something to speculate on.

Re: Timing question

Posted: Tue Nov 26, 2019 6:02 pm
by Jodaddy
Just picked up the scooter. Supposedly just died one day. Has fuel compression and spark but it won’t catch. Won’t even run with the cylinder primed. Spark is blue battery is charged. Spark plug is gapped .025. Cleaned the carb twice. Tried to start it with exhaust loosened but no luck. Fresh fuel. Air screw 1 3/4 turns out. Tried airbox off no luck. Filter is clean and oiled. Pulled the reeds no daylight peaking through. After all that I pulled the flywheel thinking maybe the timing is off. The key is present. I hooked up the timing light and and turned the motor over with a drill. That’s where I saw the light coming on in the wrong spot. If I did something wrong or stupid please let me know. Thanks. Joe

Re: Timing question

Posted: Tue Nov 26, 2019 6:54 pm
by bonesv
Well, if you use something to gauge top dead center thru the sparkplug hole then you would know the timing mark is just past the timing notch being correct. 2-stroke fires on every stroke so to think it may be firing at bottom dead center is incorrect. Possibly the exhaust pipe is clogged or has a serious leak? Possibly an air leak at the intake somehow?

Re: Timing question

Posted: Tue Nov 26, 2019 8:29 pm
by Jodaddy
Two marks on the flywheel”t” and “f”. I put a paint stripe on the F and cranked the motor. I assume the light should flash when the f passes the the timing mark in the case. It does not so I was wondering if the that would in indicate incorrect ignition timing or whether this is not a valid test since the cdi could Change spark timing during cranking speeds. Thanks. Joe

Re: Timing question

Posted: Tue Nov 26, 2019 8:51 pm
by vintagegarage
Left side crankshaft seal has blown out. Pull off the front belt pulley and put the seal back in place.. then take the scooter for a ride with a grin on your face..

Re: Timing question

Posted: Tue Nov 26, 2019 11:00 pm
by Jodaddy
I wish I was that lucky. There was some oil so those seals will be replaced. Thanks. Joe

Re: Timing question

Posted: Wed Nov 27, 2019 12:33 pm
by nateberrier
Will it start with a little ether? I know that people say not to do that too much but its worth a try. if it sparks to life then it could be the bystarter or the little passage in the carb bowl for the bystarter circuit. It can make it really hard to start esp if youre kicking

Re: Timing question

Posted: Wed Nov 27, 2019 12:54 pm
by Jodaddy
No luck with it primed unfortunately

Re: Timing question

Posted: Tue Dec 03, 2019 4:41 am
by kuromi
Is fuel definitely getting to the cylinder?

Here's a link to some stuff to try (some already suggested above)

https://www.2strokeengine.net/2strokeen ... ooting.php

Re: Timing question

Posted: Tue Dec 03, 2019 9:33 pm
by harleyracer59
has the flywheel ben replaced? I think other model flywheels have same taper as af05e and could possibly be swapped in. that's the only thing I could think of if you say all else is correct

Re: Timing question

Posted: Wed Dec 04, 2019 12:46 am
by bonesv
harleyracer59 wrote:
Tue Dec 03, 2019 9:33 pm
has the flywheel ben replaced? I think other model flywheels have same taper as af05e and could possibly be swapped in. that's the only thing I could think of if you say all else is correct
Now that's thinking outside the box! He would need a correct flywheel to do comparison.

Re: Timing question

Posted: Wed Dec 04, 2019 7:31 pm
by harleyracer59
bonesv wrote:
Wed Dec 04, 2019 12:46 am
harleyracer59 wrote:
Tue Dec 03, 2019 9:33 pm
has the flywheel ben replaced? I think other model flywheels have same taper as af05e and could possibly be swapped in. that's the only thing I could think of if you say all else is correct
Now that's thinking outside the box! He would need a correct flywheel to do comparison.

lol. thanks.
I mark all my flywheels and rims with what they came off of. I think it was my abo7 flywheel that I put on one of my af05e's. the pick ups are in 2 locations and will mess with timing.
I know the cdi can be swapped between models. the 83-84 ab07 aero cdi is the fastest stock unit ive found. the 84 nn50 gyro cdi is close but not quite as fast. they both put all the af05e (variated or not) to shame.

Re: Timing question

Posted: Thu Dec 05, 2019 8:22 am
by vintagegarage
Jodaddy wrote:
Tue Nov 26, 2019 11:00 pm
I wish I was that lucky. There was some oil so those seals will be replaced. Thanks. Joe
Joe,

1. Please confirm that you actually looked at the left crankshaft seal with the front pulley off and have confirmed that the oil seal is properly seated. Your answer wasn't clear to me.. thanks..

2. When you measure the vacuum pressure at the nipple where the hose to the fuel valve connects to the intake manifold, what does it say. Does it fluctuate properly?

3. Does the engine fire when you remove the exhaust system and turn the engine over with the key on?

Re: Timing question

Posted: Thu Dec 05, 2019 3:10 pm
by Jodaddy
Seals got here replaced left side. Installed new coil and cdi finally made it run it needed quite a bit of coaxing and it won’t idle on its own. The coil failed the resistance tests so I bought a new one and the cdi just came with it. Tried all combinations of new and old parts but it will only run with the new stuff so far. Right now I am in the midst of resealing the intake so I can check that off the list. Have to buy some new gasket paper since the stuff I have is really thin or cork which is probably too thick. Any thoughts? The starter is probably worn out. It does spin but as soon as it catches it stops and the solenoid clicks. I wanted to make sure the motor runs before replacing the starter.