[SamFraser1986]

Hello all,

I have a 2000 trail boss i rode for a year. it ran very rich (plug black and exhaust smelled of gasoline) once it got warmed up the engine would bogue down or hesitate after 1/2 throttle. It would shut it down on its own eventually and was unable to restart it again. i would wait a half hour and would start up again. One day shortly after that happened it would'nt start at all.

After that day, i drained the tank and line and tried to rebuild the carb, (carb adjustments and jets were stripped) I replaced the carb with a brand new oem $$$ ouch. checked valve clearance and was tight so readjusted them to .006 at true TDC. (used gauge to check if i was bottom or top stroke @ TDC on flywheel) Still no start

Compression test at 110 psi and held all night (apparently pretty good for a motor with built in decompression valve)

installed new spark plug and coil
no start

i opened top end of motor inspected and polished valves re aligned cam gear and chain to TDC of flywheel. still no start.

I opened flywheel housing seen a lot of rust, removed flywheel and inspected wood ruff key and was good, Stator looked melted. i ordered a new one and removed stator backing plate to look at crankshaft timing gear to see if it sheared its wood ruff key. removed and inspected it was good. reinstalled everything in reverse order including new stator and pick up coil with new electrical harness back to CDI.
still no start.
FYI when i got the atv there was no battery in it and it ran fine (pull start only) i think thats wheat melted the stator, having nowere to send its charge?

when i turn it over the plug gets wet and once every 5-10 turns it fart out the back of the carb. (i believe that means timing issue?)
Mechanically i know the motor is timed and have re timed it several times

So i have spark, bright blue
i have fuel, wet plug
and i have air
it has to be timing.

**No amount of gas in the plug hole or starter fluid in the carb intake helps either**

with a new stator
a new P/U coil
new battery
new plug
new coil
all i realy have left that has anything to do with timing is my CDI?
somebody please tell me i am missing something.

 

[polman500]

The original flooding issue was probably nothing more than the choke cable being rusted/stuck so the choke was staying partially on all the time. (very common).
Running it without a battery is what fried the magneto and maybe other stuff too. Have you checked the regulator/rectifier...it's likely toast.

When timing, did you make sure it was on TDC on the COMPRESSION stroke?
If not, then it is 180 degrees out of time.

If you're sure you're getting "bright blue" spark ALL THE TIME...then it has to run.
If not getting spark consistently disconnect the black ground wire from the limiter/CDI and try it.

 

[SamFraser1986]

as for the choke cable being stuck it originally would not start without full choke, and would shut off or die if i left it like that, i would have to turn choke all the way off to get it to stay running after starting

yes i am positive the piston was all the way to top of cylinder at TDC ( i know there are 2 times the fly wheel will read TDC at fully compressed and fully decompressed.

there a tool you can use to check, however i used a small brass dowel.

i am not sure how to test the rectifier without getting it to actually run?
any suggestions?

 

[polman500]

Yep, the piston is at the top twice during the 4 strokes...Once on the compression stroke and once on the exhaust stroke. Unless you watch the intake valve open and close while turning it it's very easy to have it on the wrong stroke at the top.

 

[SamFraser1986]

hmmm, so every revolution of the flywheel equals 2/4 strokes?

i understood that as long as your flywheel TDC marks were lined up, your piston was all the way up and your cam lobes pointed down that was how to time the motor.

is that wrong?

 

[SamFraser1986]

so you were right the rectifier is also shot. i diode tested and i have very sporadic reading and no reading on 2 of the 3 charge coil wires forward or reverse polarity.
the dc output wires actually crumbled in my hands (red and Black)

so i will order a new voltage regulator rectifier today.

i ohmed out new stator and it seem to be within speck, so i haven't toasted it yet.

On this model the CDI has its own charge circuit from the stator and has no direct lead to the battery. do you think the CDI is advancing or retarding the timing to the point it wont spark at the appropriate time?
again caused by the no battery, burnt out stator and rectifier.

 

[SamFraser1986]

Finally fixed

Just an update. After replacing the the regulator rectifier motor still wouldn't run. i kinda figured as much but knew i needed a new one. I was shipped the wrong regulator rectifier several times and the whole process took several months.
I ordered a new CDI from Caltric and installed it last night.
The quad fired right up.

So even though i have spark, compression, air and fuel,know it was mechanically timed. The CDI was not allowing spark at correct time.

In my case a new CDI fixed the issue. Wow what a battle. The worst part of it all was my wife said it was the computer the whole time (she has little to no experience with motors at all) Moral of the story CDI's are magical devices, with widely ranging symptoms.

thanks for all the help