yy250t not starting, due to wiring (short) By sinister008 (Read 5,345 times)

[sinister008]

Last Tuesday (June 19), I took delivery of my first scoot.
Ordered from superiorpowersports as an RK MC-54B, it arrived as a Jonway YY250T.
I promptly removed the body panels and began my PDI.

I got to the part where I was to start the scoot to warm it up and change all the fluids, and I've basically been stuck at that point ever since.

After several days of tinkering around with a scoot that would do everything but start and run...
I managed to get it started after I splayed out the wires going to the CDI and the accessory fuses (in an effort to get a nice snapshot).
This was short lived because the connection I had made vibrated loose again before I could locate it, and now it won't start again.

I have plenty of experience turning a wrench, but virtually none involving electrical issues.
I have a tester and one black wire, with power (juice) going into the CDI... but nothing going out to the coil.
Therefore, I have no power going to the spark plug and the engine won't start.
It will CRANK all day (as long as the battery is charged), but it won't start.

I found the wiring diagram for the YY250T (w/ 244cc CFMOTO), but it might as well be written in some alien language.
I'm convinced it is a short, or a bad wire but I don't know the best way to locate it.

I hate to ask for such specific help, since I'm so new.
But I hate the idea of cutting the wiring harness loose, because I'll have an even bigger mess on my hands if I do.

I'd be grateful for any help.
Thanks.

[scooteraddict]

This might be a stupid question but did you check the kill switch on the handle bars?

[sinister008]

You may think it is a stupid question, but it isn't the stupidest one I have gotten.
The answer is, of course... YES.

I also understand how it is customary to assume that all newbs are unable to
locate their sphincter with both hands and a map, but I assure you I can.

What I really need is for someone who knows the wiring on this thing to tell me
from the symptoms (which I can provide), the best place to search for the bad connection.

In other words... from where I have power, tell me where I should have power, but do not.

Does that make any sense?

Like I stated before, the last thing I want to do (with my limited knowledge of wiring) is to
cut all the wires off and try to rewire it all myself.

What a frickin' mess THAT would be..!

[damin69]

Jr Knows these wires like the back of his hand. I assure you that you are in the right place to get help with this problem.

[JR]

First of all Welcome to the forum! Now lets first establish what scooter as in the engine you have and we'll go from there. So even though it is labeled the YY250T which is supposed to be the vertical cfmoto copy it could be labeled wrong and be the horizontal linhai and here is a picture of both engines;



Now it doesn't matter which one because we have a diagram of both and they are very close to the same.

thescooterprofessor.proboards.com/index.cgi?board=250g&action=display&thread=430

It's the first one or if it's the linhai the seconds one. You will also see the differences in the two which are small.

Now lets discuss the CDI, no matter which engine you have the CDI is the same;



So here's the pin out on the CDI;

Black = 12Vdc from battery (this is a DC powered CDI)
Green = ground
Gray/white = engine kill wire
black/yellow = feed to coil
red/white = signal pulse wire from stator

Now there are several things that need to be checked and since you said you give it the old giggle the wire and it started but now it won't that's a dead giveaway so it's a matter of figuring out the gremlin that's causing this BS.

Now you are correct on the black wire having power and it is 12VDc from the key switch when it is on. The key switch is fed from the red wire from the battery that has the 15A fuse. I would remove the harness wrapping that holds the wires to the CDI and pull the plug from the CDI and put my volt meter lead on the black wire and turn the key on. The black wire form the key ignition feeds several things and splits in the harness and the Chinese are famous for using cheap brass crimp connectors to splice the wires. With the key on and volt meter connected move the wires around and see if the voltage goes on and off. If not then move on to the gray/white wire, if it does then you've got to trace it out and find out why.

Now the gray/white wire as mentioned is the engine kill wire and it works by simply grounding out the CDI when the key is off or the engine kill switch is pushed to the off position. If this wire is shorted as you say which would mean it's grounded out then no voltage from the CDI to the coil. This is possible, remember the moving the wires and it started? You got to remember these wires are in the harness all together which includes the green (ground) wire. If it is bare somewhere in the harness and touching the ground then again no power from the CDI to the coil.

Now we can test for this, unplug the gray/white and black 2-plug and take your volt meter, set it to ohms and do the following;

(1) put one volt meter lead to the gray/white wire and the other to ground
(2) turn key on
(3) Check the meter to see if you have continuity or ohms resistance, with the key on and the engine kill switch in the run position you should have no continuity as in no ohms resistance. If you do then you have one of 3 problems;
(A) gray/white wire is shorted out to ground
(B) key switch is bad and not opening the kill circuit with the key on
(C) engine kill switch on handle bars is bad and again not opening the circuit when in the run position.

Now there is also a easy way to check out the gray/white on the CDI to see if it's the problem. When you unplug the 2-plug look at the end of the plug, all these plugs have a little small slot in the end by each wire in the plug. You can take a very small screwdriver and insert it into this slot and it will force the locking ear on the connector to let go and you can remove the wire from the plug. Remove the gray/white wire and then plug the plug back into the CDI with the one black voltage wire still in the plug. I would remove the spark plug and lay it on a grounded spot and turn the engine over to see if you have spark. If so then re-insert the gray/white wire and see if the spark fails, if so then you've got to determine which one of the 3 possibilities it is and fix it.

The reason I say remove the plug is if this is the problem then with the gray/white disconnected you can't kill the scooter with just turning the key off if it started.

Now if these two wires check out then the next wire to check is the green ground wire, if the CDI isn't grounded then no voltage to the coil.

If it is good then the next wire to check in the black/yellow to the coil from the CDI, they are famous for having bad end connectors on the end, I personally soldier all of mine.

That should head you in the right direction and remember we're here to help.

JR

[sinister008]

Jun 29, 2012 21:46:45 GMT -6 JR said:

...and remember we're here to help.

JR

JR, I don't know how to thank you and Cruiser and everyone else who contributes to this community.

After I had no choice but to cut into the wiring harness and trace out the problem...
I found half a dozen or so other "issues" that would have become problems eventually.

I guess I just needed convincing that there was no other way.

So, the problem I seem to be having NOW is that in the two weeks since I took the fool thing apart,
I have forgotten just how, and in what order, all the body panels get bolted back onto the frame.

Do you happen to know of a "reassembly cheat sheet" I could get for my YY250T?

If you do please let me know, because I have just completed failed attempt number one
since I'm not going back in that garage until it cools down some.

I just seem to be having trouble getting everything to line up,
and I'm sure it's because I'm putting things together in an out of order, awkward way.

Again, thank you very much for your help. ;D

[JR]

Yes to a degree. Here is the Honda manual section and click on the Reflex service manual ;

thescooterprofessor.proboards.com/index.cgi?board=ncmanuals&action=display&thread=415

This scooter is a copy of the Honda Reflex and on page 42 is starts the body panels and an order to what they are in. Now Honda usese clips and other things to put their panels together while the Chinese use these millions of screws! But the panels and body parts, even the windsheild is identical.

This should steer you in the right direction. Also a suggestion is when removing things the first time take pictures and also use bags or cups to put the right screws with the right part, believe me it's a lot to remember and sometimes I look down and have to say "wonder where that screw came from!"

Also we thank you so much for the compliments. We truly try our best here to help folks with these sometimes difficult scooters.

JR

[bobf]

I have a YY250t, 2008 MC 54 250B, with the Honda clone. I recently had my covers off to fix the seat latch. I don't know just how far down you went to fix the problems. So I start at a lower level.

If removed, first is the floor cover, then the foot pads. Also if removed now would be the time to install the side dress panels under the foot rest area. Then arrange the rear side panels, mine were both connected at the rear so they went on together. As you are getting the side panels arranged find the tail light cable connecter and attach it to the cable on the right side under the right rear panel. Also make sure you have replaced the key lock and cables on the left side panel. Then complete the rear side panel arrangement and put in the screws. Put the small panel in above the tail light assembly. Move up to the two tubs above the engine. Put in the rear tub first then place and mount the front tub. Now you need to install the spring bracket for the seat. And finally the seat itself.

The last step would be to install the carrier and trunk. All together they only need three bolts installed to hold them. This can be done before or after the seat is installed.

I hope I did not miss anything.
.