Scoot died, NEW STARTER, still doesn't start  By  murkyapricot (Read 14,863 times)

when you first checked the valve lash , what was it set at ? or did you just redo them without really checking .

i may have missed it , but did you already know how to set the cam or did some here tell you how ?

I already knew the orientation for TDC for the cam ive done the valve lashing quite a few times, I was more concerned that maybe i put the chain back on wrong, ill have to go back and check the Freewheel marks

The valves were already .004 and .005 intake/exhaust

That was the first thing i checked when diagnosing this issue

At this point Yes, pony up.
If your Compression test is Correct this will complete a Top End Re-Build.
A Decent sealed up GY will have about this for PSI.



I got in on your issue late I would have recommend this Cylinder Head First and or in the Addition to the new Cylinder and Piston Assy.

I have not, this is not something I previously knew how to do, hence this topic, so I can learn

Also I never said I replaced the coil, just tried a different cdi, but it was giving spark

Also would a short in the wiring cause it to have low compression? Or would a weak starter cause the scooter to shut down mid ride? Sorry this questions might seem stupid but I'm still figuring out exactly how everything influences each other.

Also if you look at the pics I posted there is some chipping on the head near the valves, not sure if you're saying this is fine or not?

well, now is the time.
a top end rebuild is the perfect time to "get it right"

like i said earlier, the CDI works or it doesn't.
it's the coil that can appear to work, but it fails to work under load of compression.

no, but it will keep the engine from starting, even though everything else was perfect

no, but a short would.

a short in the wiring robs your system of the power it needs for the spark.

didn't you say you did a top end rebuild?
this to me implies a replacement of the head, cylinder, and valves.

what i'm trying to say here is, if you can't get it running sitting on the bench, then it will never run in the scoot.
now is the time to inspect and verify all of the components.
this not only includes the top end, but also the stator and pickup, especially the pickup, because this is what provides the pulses to the CDI.

now, for a little in depth.
get yourself a DC CDI for bench testing the engine.
also, provide a kill switch for the pulse pickup, do not attempt to short any of the CDI outputs.
use this kill switch to shut off the engine.
wire the CDI, pickup, and coil, and leave the stator wires open, do not ground them or connect them to anything.
disconnect the autochoke.
use an ohmeter to check for grounds between each of the stator wires to engine.
these readings should show an open circuit, or with a digital meter a very, very high number.
leave everything disconnected except for the following items used to start the engine.
you will need a battery charger, and keep the battery on this charger except when using it.
wire all the stuff up (kill switch, CDI, coil, and spark plug) and attempt to start the engine.
you really don't need to bolt up the carb or exhaust for bench testing.
also, keep your area clean around the engine, no rags, paper, gas, bird nests, or anything else that can catch fire.
make sure the engine is solidly mounted, put it back in the bike frame if you have to.
remember, all you are trying to do is get it to start and run, you aren't checking that the lights, horn, fans, signals, gauges, or anything else works.
ONE THING AT A TIME.

scoot batteries have screw terminals.
get a piece of black heavy gauge starter wire and connect it from the battery to a suitable place on the engine, one of the starter mounting screws would be perfect.
get another piece of red heavy gauge starter wire and connect it to the starter terminal, you will touch the other end of this wire to the battery positive post to start the engine. (beware of sparks, this wire can become quite hot if it isn't heavy enough. wear a leather glove on this hand, get a heavier wire if it gets hot. also be aware that you need to "stick it on there" don't be scared, this will cause the wire to weld itself to the battery).
an even better approach would be to use the existing starter solenoid.
in this case connect the red starter wire to the solenoid and run another heavy gauge red wire from the solenoid to the battery positive post.
run one of the small solenoid wires to the battery negative.
touch the other to battery positive to engage starter. (this will be a lot better than manhandling a direct to starter wire)
wire up the pulse pickup, kill switch, CDI, coil, and plug.
squirt a little gas into the carb inlet or direcly into the intake manifold.
flip the kill switch to run and touch the red wire to the positve post.
the above process will start the scoot.
use the kill switch to shut off the engine.
this isn't a "brake", all it does is remove the spark.
if any of this isn't clear then let me know.

*WARNING*
gasoline is serious stuff. it ignites easily.
only have small amounts around your engine when working on it.

Don't have the patience to go back and read all that crap I wrote -- but certainly didn't mean to say it's "smooth" or easy to turn the engine by hand (unless the plug is out).  All I meant to say involved using the starter motor.

The question I have is if there really IS low compression.

If when checking the engine the starter turned it over as it did in the video --- or if compression was tested with the throttle closed ---- we do not even know if the thing is bad compression wise.  Need a proper and accurate compression check.