TAO tao rebuild gone wrong (siezed) By case (Read 1,810 times)

[case]

Hi guys!
I have this scooter, its a 2012 tao tao. The owner had " rebuilt"
the top end with new head (he said) and piston. The guy said it had siezed up and he didnt know why....when I got it I tested the compression with the kicker and it seemed fine, so i checked for spark and decided to fire it for the hell of it.
I fired it and it ran for 20 seconds made engine noise and seized up. the piston seemed locked.....I began to rmove the head and cylinder...the head popped off and the cylinder came free from the piston easily, the piston was not scored or streaked or damaged...I grabbed it and rotated the engine and it became "unstuck"....weird, it seemed like the bottom end was stuck for a second.....When I was removing the head I realized there were no bolts intalled holding the head to the cylinder...see pic 3.....I wonder if this was the problem? did he just froget to put in the head bolts and the thing was vibrating until it siezed? Pleasehelp me decide what to do next. there is a small score on the inside of the cylider wall now, should I sand it smooth? what grit?
Should i put it back together and try it again with the head bolts attached or just buy a 80cc kit and be done?
I am worried it is the bottom end, is that likely? I can grab the piston and rotate the engine byhand and everything seems/look smooth
The guy said that he put on a new head and the one he gave me is the old one, but it is sqeaky clean new.
I hope he just made a mistake when putting it back together....what are your thoughts guys!!!!
Thanks.
the pics





Also, when i got inside and looked at the valve lash, the intake valve was set at1/4 inch....and the exhaust lash was so tight i could not move it at all.
what do these things tell me?
thanks guys for all the help

[retardninja]

Hello. I have no idea on if you want to sand and all that but I know I wouldn't. You have your scooter ripped apart just like mine for a second I thought I had hit the back button and was looking at my own video again. Anyways, I found my big bore kit for $54 and maybe you should just consider doing the same. Check out my brand new totally awesome video where I play show and tell with my stuff here (it's not like that-get your mind out of the gutter).

[Alleyoop]

WOW! He forgot to put in the TWO HEAD BOLTS, sure put those head bolts in and give it a shot. You relly do not have anything to loose.
Alleyoop

[case]

Thanks guys. i figured out the seizing problem....I think.
not only did he not put 2 bolts in, the cam chain was not around the rear gear in the block!!!! He tightened down the cam when it was clearly off, and cranked it up, the cam chain got stuck after a few rotations and blam lockup. After tearing down and reassembling the motor about 3 times, i realized that. I put the chain on the rear gear, and put the pistion at tdc, and put it back together. Now it turns and turns , no lockup, but it wont run....I am getting spark. it will crank and crank and sometimes go "put"
So I hope ???there is nothing wrong with the engine as far as seizures go, but It wont run, so Im still tryin
help valve lash set at .013
but its not "seized" anymore and seems to have good compression
stumped now and tired.
thanks guys
Case

edit; holy crap.. fired up and ran like a top!!!!!
csae closed.
thanks again fellas

[retardninja]

I wounder if that is what is going on with mine. I guess I never thought about the rear sprocket. omg idont want to tear this thing apart again

[Alleyoop]

WOW!! Unbelievable, no wonder he sold it did not know what he was doing and because it was locked up he sold it. But know you got a running scoot.
Good JOB
Ride Safe
Alleyoop

[case]

hey thanks Alleyoop, and Retradednija, tear it apart and do it again, and again and again. I spent 10 hours today on this.
Ending up in a final ride up and down the street a few times, it bogs and wont idle , but accelerates ok. I assume the carb is all jacked up as well, so fuel sysyem overhaul tomorrow. It has a racing cdi, racing coil, pod filter and new jets came with it.(in a little baggy) Far as i can tell an "upgrade kit" with new piston, coil, head, cdi, and pod was installed and somehow the cam chain slipped off the gear in the block, it was tricky, but I could tell something was "not right" with the way the cam gear fit in before tightening up.
Hope this helps someone.
Case
oh and the pics of it back together afte a 5 min ride.


brand new jets...look big when you hold them up and look thru

There are alos a bunch of assorted parts in bagies, valve springs and crap
and a brand new head, didnt need it, this one looked good.
Thanks guys hope I get her purrin after the clean and jet

[Alleyoop]

Yep that is all it is now, clean the carb and pilot jet and passage out and adjust the fuel ratio mixture and you got a nice running scoot.
Good Job
Alleyoop

[case]

Ok, so I ran the scooter. It seems to start well and throttle well until it gets just a little warm and then nothing, or it will barely idle, if you give it the slightest amount of gas, it will stall.
Sometimes at that point it will backfire some gas from the carb in a spray and then act flooded......I tried 2 enrichers and cleaned the carb twice. I have adjusted my valves until i am blue in the face and still the same problem.
As soon as it gets to operating temp, you cannot apply throttle.
compression seems fine
spark is ok even when hot
Getting plenty of gas
check valve ok
makes a sucking sound when you give it gas and dies.
manifold seems ok
hoses seem connected right
Alleyoop and the rest of you wise ones
please help
arrg

[Alleyoop]

Well it appears it is a FUEL DELIVERY problem, it works good when the ENRICHER is feeding it fuel and when it cuts off the extra fuel that is when you have the problem.

Appears it is sucking to much air and not enough fuel. I see you have a free flow right on the Carb so it is getting a lot of air.

So do this after it gets warm, do not touch the throttle. TURN THE FUEL RATIO SCREW COUNTER CLOCKWISE 1/4 turns at a time and see if the IDLE GOES UP if it does REPEAT the 1/4 turns until the IDLE DOES NOTHING and give that a shot.
Alleyoop

[case]

Thanks bro!!
i had the mix screw at any setting from 1/2 to 4 turns out and it doesnt make much difference when idling hot. When ice cold it makes a little difference. This morning it fired right up, i rode it, very slow. Then it stalled and wont run all day....one time i got it runnin and it would idle no problem but stall at the first sign of throtle.

[Alleyoop]

Ok, you said the magic words turning the screw does nothing. Now turning the screw clockwise until it stops SHOULD KILL THE MOTOR(DOES IT)?

From you said you had it turned 1/2 from the closed position and 4 turns out and it did nada. THAT TELLS me the PILOT JET is WAY TO BIG and that is why it is a PIG(no power).

Wat size PILOT JET is in there?
Alleyoop

[case]

Im not sure of the jet. Is there a way to identify? there were 2. after lookng at the plug, i changed from the large to the stock?
one. Turning the screw had little fluctuation of idle even to fully closed. This made me belive the enricher was stuck , but i tried another.
I know this must be something simple
I hope......it seems like the choke is stuck wideopen and after it reaches temp it floods.
thanks for the help !!!!!

[Alleyoop]

You can test the ENRICHER and see if it is shutting off the extra fuel after 3-4 minutes.

Take the enricher off before you start it and lay it on its SIDE so you can see it.
THEN cover the hole with your thumb and start the motor and hold your thumb on the hold all the time. Now watch the enricher as it is warming up idling the PLUNGER on the ENRICHER should start to EXTEND out about 1/4 of an inch or so with 3-4 minutes.
If it does it is working and your pilot jet is TO BIG.
Alleyoop

THIS IS HOW IT SHOULD LOOK WHEN YOU FIRST TAKE IT OFF:



THIS IS HOW IT SHOULD LOOK AFTER 3-4 MINUTES OF IDLING:

[case]

what.
its supposed to come off like that? even when warm, niether of the enrichers did that, at best warm, the tip came out a millimter or 2 but niether one looked like that.
hmmm. the other enricher was from a junk bike.
also,is there an o ring that is upposed to go in before the enricher?
I willdo the experiment if the bike will run long enough....thanks, i was thinking it was the enricher, if the jet was too big it would still run fine when cold?
because it revs and runs ok when cold
dang scooters are hard to fix sometimes.
oh well, happy 4th fellas, tomorrow may be a better day, although i think the privious owner really did a job on this and its hard to fix