missing ground wire? By millsc (Read 8,195 times)

[millsc]

I'm doing a job on angel 50, it had no compression, the person took it to a local shop here in town and was told they need a new motor and it would cost 700 bucks. So they brought it to me instead i put in a new cylinder, piston and head all went smooth and compression returned. But it won't start it cranks fine but doesn't attempt to start, i changed the coil cdi and carb still nothing, it only has one ground wire on the battery and i cant tell where it goes. Theres no ground wire on the valve cover or frame i'm thinking this is why its not firing, but the plug does spark when i put against the valve cover in the coil.

[tvnacman]

Pull a heavy wire from the neg battery to the frame and to the engine . I would splice into the greens in the harness and make sure it connects to the ground wire you add .

John

[millsc]

wonder why it didn't have it grounded to frame stock? All the others i've worked on at least had a green wire on the valve cover.

[tvnacman]

I don't know, why not ask Alley ?

John

[millsc]

hopefully that's the issue, it cranks fine just won't start.

[rob63]

If you`re getting a spark when placing the plug against the valve cover then I would think that there is some earth connection between frame and engine somewhere. On most gy6 motors I`ve come across the earth lead bolts to the crankcase just above the fan cover.
Out of curiosity what compression reading are you getting ? I`ve had a couple of brand new Chinese heads recently where the inlet valves were leaking, compression seemed to be there but when I popped the tool in the plug hole a low reading came up.
Assuming that valve timing is correct and you`ve got a spark and correct plug fitted, then that only leaves fuel and air.

[millsc]

compression is 150 the gas doesn't flow out the gas line as strong as id like but the carb is full when take it off. I tried four cdi's i had had in my stock pile i'll try the one off my scoot since i know it works for certain. What is scary is that it had a compression reading of 40 before i replaced the piston and head it was ran out of oil, is why i'm worried other stuff is destroyed even though it cranks fine.

[Bashan]

I'd run a good ground from a bolt near the plug to the nearest frame bolt and then make sure there's another cable from there to the neg battery terminal. It may be grounding back through the case somewhere and the spark isn't adequate. I had just that problem before. I think that is what John is also suggesting. It's worth trying.

[bo]

are you sure it isnt 180 degree out of time sound like it if its gitting fire and wont start my 2 worth bo

[millsc]

update i put a different cam in it and it fired right up, its gone, job complete.

[Alleyoop]

What I believe is that you had it timed wrong, for a cam to not let it fire it would have to be a very high profile cam. And for the 50s they just are not that aggressive.
Alleyoop

[millsc]

could be, i like to think it was perfect since ive done it at least 30 times, i could be wrong though lol. The cam i took out rolled rough like sandpaper

[Alleyoop]

30 times or 50 time if your off 1 link that is 10% off timeing in either direction. That is why I always tell people before they take the cam or chain off bring it up to TDC PUT A MARK on a chain link and the tooth of the cam and also mark the FLYWHEEL where the timing is pointing at. That why you will not be off 1 link.
Alleyoop

[millsc]

I believe it was correct i check tdc with piston in the jug , it did line up to the t mark on this scoot, i had problems with timing on my big bore kit the first time i did a kit i make sure its exact.

[Alleyoop]

Whatever, but it was not the cam.
Alleyoop