I've searched high and low, still no definitive answers, so heres my story.
About 6 months ago I bought an fl350r.
Guy claimed it was freshly rebuilt and properly broken in. Everything replaced, leak down tested
Compression at or near 150 psi. New seals, ect, ect, ect a complete motor (( Internal Combustion Engine ? )) rebuild. Only thing was the starter wouldn't engage. (It would pull start first pull everytime and run like a raped ape) but the starter would spin, just not engage. Was told it needed a oneway bearing. So I bought a brand new starter. After killing a few knuckles, I replaced the starter, got it all back together. Long story short, wasn't the starter but a bad cell in the battery. Thanks Methodical for that bit of info. After all that work and a new battery, it ran like a beast. The GPS, after 3 passes around my neighborhood, stated I was averaging close to 65mph. But on the 4th pass she starts to bogg down at half throttle and continues to go slower and slower until she dies. I searched and found a wire from the stator to the connector, fried and I mean crispy, crunchy fried. A facebook friend had a used stator in an old motor (( Internal Combustion Engine ? )) he had on a shelf and sent it to me. A little dusty but looked almost brand new. I install it and bam, back to screaming. So I'm out ripping it up, burnt a full tank of fresh gas, mixed at 32-1. And again she starts to bogg down as she did before. Thinking the stator wasn't the problem I started changing all things electrical. Replaced everything with new parts, the solinoid, the coil (twice), the CDI (Capacitor Discharge Ignition) (from a running buggy), grounded the DNR switch, rechecked the leakdown (holds pressure over 30 mins), rechecked compression(the same,150psi), cleaned the carb, replaced the fuel lines and fuel filter. Replaced the pulse hose and fuel pump.Tried running without silencer (it was clean) tried running without breather box top with a new air filter. No, there was no oil on or in the starter or stator. The motor (( Internal Combustion Engine ? )) was completely rebuilt and spotless. I've researched for months, asked everyone who would listen and answer. Ive tried everything everyone had recommended. My last attempt is to install another ground wire from the motor (( Internal Combustion Engine ? )) to the frame using a starter ground wire off of a riding lawnmower. I do have another new stator but wanted to rule out every possible problem so I don't burn though another very expensive stator.
Anyone have any ideas where I should start looking? The buggy starts (with some effort), idles (when warm) and runs, just not over half throttle. Motorcycle shop claims it's running rich and that a carb tune is the answer. My gut tells me its electrical as it ran like a beast each time I changed the stator.
Any ideas or where I should look or what I should try?

Hello new guy.
I don't show up here very often anymore and neither do many other members. Unfortunately this site is very very slow now.
You appear to be mechanically inclined.
You have also left out some important info but I will try to work around that.
In my opinion almost all of the problems are a result of shitty fuel flow and the occasional and I do mean occasional electrical problem.
You will do the following:
1) Check your fuel tank - is it rusty inside ? Are the pickup tubes clear ? Fuel filter ?
2) Flow test on your fuel pump at idle. You MUST get 4.5 oz in 10 seconds flow or better. If less than that then you're dead. You WILL lose an Engine.
3) If it passes the flow test then it could be your coil. Check ohms. Here is a thread I did on one of mine: viewtopic.php?f=1&t=18792&hilit=coil
4) Is your machine still air cooled ? If it is you must run AVGAS. The air cooled Engine gets no cooling because it's behind the seat and that causes elevated intake charge temperature and you melt a piston due to detonation.
5) Your oil mix seems to be a bit rich. My machines are water cooled so I run 50/1. I don't know if your Engine is air or water cooled.
6) You said your machine run over 60 mph ----- Yup that is correct. A stock oddy will do 63 mph. Check this thread: viewtopic.php?f=1&t=19752
That also tells me that your jetting and other stuff is correct.
CO

You said: "The buggy starts (with some effort), idles (when warm) and runs, just not over half throttle".

I bet my rent money it's a fuel flow issue and NOT electrical.
You need to post some pics bud.
A lot of problems have been solved here by guys posting pics.
I need some pics of the fuel system area and your machine in general.
CO

I will keep tabs on this site for a few hours and then I'm gone again.
CO

Yes, its getting proper fuel pressure. (4.5 per 10 seconds)All hoses have been replaced including fuel filter. But just to be safe I tried both an new Oddy OEM pulse fuel pump and the (supposedly) higher output rectangle pulse fuel pump. (Made no difference between the two)

I have tried "everything" that others have recommended repeatedly. Like I said, my gut keeps telling me its electrical cause it ran like a beast everytime I changed the stator. (2 so far) I was told it would run like crap if the stator was bad. And it's running as described, falling on its face at half throttle.
I believe when the Engine was rebuilt they forgot to add the Engine to frame ground, as I was told no/bad ground would cause the stator and any other electricals to burn out, that it would follow the nearest ground path and short that wire out if it couldn't handle the voltage.
Plus the motorcycle shop I took it to said it was running rich. (They drove it) If it was a fuel problem wouldn't it run lean due to lack of fuel?
I've worked on many 2 stroke motocross bikes, but this buggy is kicking my butt. As for pics, the buggy is bone stock, everything in place as per factory specs. No mods. Its air cooled and never ran hot enough you couldn't touch it . I even used an infrared thermometer, never reached 250 at its hottest. It just doesnt make sense.

The fuel tank is near mint condition, no dents dings, or rust. Looked brand new until I scratched the paint taking it off and on.
The coils (have 3) 1 is stock OEM the other 2 are the bright orange high performance. New plugs as well.

You said: "Like I said, my gut keeps telling me its electrical cause it ran like a beast everytime I changed the stator. (2 so far) I was told it would run like crap if the stator was bad. And it's running as described, falling on its face at half throttle".

At this point I'm inclined to believe you in the electrical theory.
In the two threads I'm going to post links to, that's what happened to those guys based on what you're saying here. My only issue is that these stators RARELY go bad and same goes for the CDI (Capacitor Discharge Ignition) units. They're almost bullet proof.
My next question is -- did someone butcher the wiring harness ? Did someone mickey mouse new wiring in ? Just asking. If they did then I have no confidence in that job.
Here are the links (I know they are FL250's but symptoms are the same):
viewtopic.php?f=31&t=18496
viewtopic.php?f=1&t=18349
CO

Please click on this link for valuable info: viewtopic.php?f=2&t=18393&p=177700#p177700
Anything that is highlighted in blue in that thread can be down loaded.
Lots of good stuff.
CO

My 2 cents,
You said you think the Engine ground was removed... there should be a ground wire on the lower front left motor (( Internal Combustion Engine ? )) mount, also you can take a multimeter and test for continuity from your Engine to frame ground, it should read 0.
Another thing to check with a meter is the stator; the specs for what it should read will be in the service manual.
Also have you looked at the spark plug when it was running good?

This is a good read……

A stator is nothing more than a laminated iron core with copper wire wound around it. That being said there is very little that can fail on them. Typically what happens is the coating on the wire burns off causing a short to ground, when this happens the stator can no longer produce current.

Often what causes this is heat or overworking the stator. Trying to charge a battery that is bad will cause the stator to work much much harder producing amperage that the battery will take, the end result is once the amperage gets high enough the coating melts off the coils causing a short..

Corrosion takes a part in this as well, as the stator has to work harder to push current into the battery again working hard.

In a batteryless system adding more, powerful lights and accessories will cause the same issue. Generally stators without a battery designed into the system can power 35 watt lights at maximum.

A short in the wiring from the stator can also play a factor in this but 90% of the time a stator fails when the insulation melts off and the coils short out. Failing on its own without being overworked should be almost a non-issue. There's no moving parts to wear out, and most of them are bathed in oil which should eliminate the possibility of internal corrosion.

If you're burning up stators Have your battery checked as well as the wiring going to the voltage regulator. The wiring can be verified with a multi-meter set to check continuity. Your manual should have steps for testing your particular stator.

Are you running any high draw aftermarket lights? Grip Warmers? Seat warmers?

CO
Yeah, I've read every thread on these forums and checking them as I go. The main reason I thought it was electrical or the stator, because the first one the wire was fried from the connector all the way down to where in goes into the Engine. At finding the burn wire I did a search and read about a bad or missing ground and spent weeks checking and rechecking every wire on the buggy. Nothing was out of place. As far as the spark plug, it was wet (as I expected it tobe) but looked good. I cleaned it just to be safe. After removing the seat I did find the ground wire bolted to the motor (( Internal Combustion Engine ? )) mount . First chance I get I'll follow it, that's also where I plan to add another ground from the mount to the frame. Mounting to a rubber motor (( Internal Combustion Engine ? )) mount didnt make sence time so I'll add another one.
Yes I upgraded the lights to LED but never hooked them up, wanted to find and fix this problem before adding lights. Also why i checked all the wiring. Believe me when I say I've done my research and gone thru everything.
All I know do to next is add the extra ground, replace the stator, cross my fingers and hope it works. If not, going to sell the motor (( Internal Combustion Engine ? )) and tranny yank out the wire harness and install the 800cc fuel injected, 4 stroke V twin water cooled rotax from a snowmobile. Just hate this problem is kicking my ass.

Just keep in mind that doing this is a really big project.
These frames were engineered for a small two stroke Engine and the sled swaps had frame cracking issues. In fact even the stock Engine will crack the frame. Also if you remove the gearbox you got no reverse. If you leave the gearbox you have reverse and they do handle rotax conversions. The weak spot on the trans is the A/B gear bearings. They get no lube if you are not moving, it's a splash lube system so don't rev the pizz out of it doing a "driveway tune up". If you blow the A/B it's over. I did rebuild a blown trans A/B gear by welding the teeth and totally re&re the bearing part of that gear. Have not run it yet as it is just an emergency spare. Also you are limited as to the rear shock length. You must run stock length or you will get u-joint bind. I did a thread on it.
At the end of the day stock set up is by far the best.
If you are a power guy then I suggest you read this thread (Please read the entire thread): viewtopic.php?f=2&t=15887&hilit=crsah
CO

Why I was trying so hard to repair this problem before attempting a Engine swap. I would really like to keep the original Engine as this buggy is complete and original.
Thanks for the feedback.
CnB aka It.only.sputters.now

Just for fun try another ignition coil.
I had a similar issue and the coil wire for the plug was corroded inside. No way to tell. I only found it by accident when I cut a small piece off the end to re-install the plug boot.
Symptoms were similar to yours but as soon as I got on the gas the Engine would die.
CO

This is the fried wire on the first stator I replaced. It WAS the green wire. Now you see why I think it's an electrical problem.

CO:
I tried an aftermarket coil, 2 high performance coils and an oem coil from a running buggy. All ran the same. I've replaced everything electrical at least twice. The last stator I bought was test before it was pulled from the motor (( Internal Combustion Engine ? )) and tested again before it was shipped to me, so I know it's good. This will be the 3rd stator. I'm a little worried about putting it on only to fry it. Now I'm told if I keep running it like it is ill fry a piston and then I'm really screwed as it's already bored out to its last bore 82mm

This is a pic of the ground at the Engine mount,
Where the arrow is pointing, isnt there supposed to be a wire from that location to the frame? As in from Engine to Engine mount, from Engine mount to frame. Or is it just 1 ground wire from Engine to Engine mount? Thought maybe the people who rebuilt the Engine forgot one. A missing ground wire would explain the two burnt stators a burnt coil and the two
burnt diodes on the FNR switch wires.

Here is a picture of mine, I cant guarantee it is 100% correct, but it works for me.
The small green wire connects to the belt guard bolt with a ring terminal.


Also there are some resistance checks you can try as well:
The Black/Red wire from the stator to the green wire from the stator
The Black/Red wire from the stator to the Engine case somewhere with the green wire unplugged.
The Black/Red wire from the stator to the battery ground terminal.

Manual calls for 50-180 ohms. Each test should read the same if your ground is good.

It should be like the picture Lanix posted.
Try the suggestions he posted.
This is definitely a tough one and you have obviously gone over everything.
I really wish I could be more help but I'm not an electron mechanic I'm a millwright. Electrical is one of my worst talents, I really suck at it.
As for being on the last bore of 82mm ---- that don't bother me a bit. I have an Engine that has a welded piston in it and it's still running fine. It also had melted aluminum on the cylinder and 3 small gouges on the sleeve that I just scrapped out and honed. It's also the same Engine that exploded on my dyno run. Like I said, it wouldn't scare me until I see monster gouges in sleeve.
Something is causing that stator to put out a lot of juice. (I think).
CO

Edit: The oddy system puts out 13 amps, so that's 156 watts.
CO

Hi every one.
The green wire Burt up due to you using your starter.
When the chassis ground from the Engine is missing the starter is looking for a ground at a high amp draw. That wire can not support that much current. This will put the stator wire in series/ parallel with the small ground wire and burn it up. This usally will cook off you voltage regulator as well. Replace both at the same time.
You must have a proper sized cable going from the negitive terminal of the battery to the frame and the same size of wire going from frame to Engine case. Or do not at any time use you starter. This is why you do voltage drop test on your cables every year or should.
DO NOT RE-JET. Untill your fix then you will find your most likely lean with proper spark and timing. In the a/c world there what's called a lead and lag to which the stator is an ac system.
Other stuff to keep in mind is a battery. This is a buffer for the electrical system. You must use a good battery all the time even if you have a bad starter and don't use it. Yes it will effect jetting. How you ask. It effects the coils output or voltage/ current to the plug and the spark it's self. The plug most run are resistive and the wire it's self has a fixed resistance. There for the voltage must fall with in a range with a given amperes. Too low and you jet down than bang it cooks off and you chase your tail.

Any way hope it helps.
Look at the wireing diagrams in the manual. Make sure all is correct
Replace with good parts
Then check your jetting.
Do you voltage checks
Do your volt drop checks
Last but least new fuses and check you voltage drop across them.
Clean all any terminals and chassis points
See any rust, deposits, dirty connections on any thing clean it up and install the proper lube to all connections.


Then enjoy

Basically you new starter was looks for a way back to the battery. That little green wire was not big enough. To much current draw across the wire and it got hot and melted the insulation and the insulation on the stator wires.
Now look the the spark it's self, ummm
The plug can only spark if there is a ground. What ground? The green stator wire. That's a lot of current across the stator as well. This most likely is what burnt up the starter and stator in the first place.
The spark plugs has to complete a circuit as well or no spark. Once there is a short in the stator spark suffers in two ways. Lack of line side voltage and load side voltage(ground).
The neither circuit can function properly.
See you all around.
Rich

And there is your answer.
I was hoping adnoh would chime in.
He don't show up much anymore on this site, just like the rest of us old timers.
Thx for chiming in adnoh.
CO

pics of the bable
hope it helps
Hi CO

The two last pics show the issue.
Pic four shows normal path from starter to battery via the ground on Engine in pic 3
pic 5 shows the path it is taking and burning up the wire.
Basically the ground will take every path available and the green wire from the stator is the fusible link in this case.
this can damage the whole wiring system that contains this ground connection. The hole wiring harness could have been effected and should be checked.

Bad day for you. if you don't this will be a gremlin for ever if with an Engine swap.

Looking at the diagram you can trace out that green wire from the stator up in ot th e harness and every thing is touches will go bad. The coil for spark may be the only save if tests are with in spec. Me I would replace all with new. and check harness.

New fuses, lamps,CDI (Capacitor Discharge Ignition),coil, plug wire,voltage regulator and stator. Hopefull you did not damage your new starter. the winding could have over heated from voltage drop and burnt one or 100. testing will prove that one or not. plus once you get to point to do voltage drop test you will have your answer.

Take your time and no short cuts, no pun intended. One short cut and its a long term issue and battle.

Ill check in now and then if you have any questions as you go and other struggle with answer.

Adnoh

I have to ask. You battery hooked up right. No reversed
I did notice in the book it said to remove the negitive cable from the starter. Oh my.

The end of your cable may need to be reworked and the pic of your ??

If memory serves on the ody and other please chime in here. The main ground from battery runs to Engine block from the battery and than the green jumper from there grounds the rest of the machine. If his ground on block is bad and green jumper or bonding jumper is missing this will cause the same issue. A #10 would be the minimum jumper I would use. I would also replace the crimped end of that cable if it looks loose or corraded the insulation in the pic points me that way.

Found this on ebay

adnoh:
You described exactly how my problems started.
Finally someone busted this mystery and proved my suspicion about the missing ground wire after the Engine rebuild.

This is the condensed version (no its not) of the whole event:
After the break-in (ring heat seating procedure) the buggy ran like a "raped ape" but no electric start.

Due to car accident and a weak shoulder I was unable to pull start it.
Has about 150 PSI at cylinder.

New starter would spin but not engage or turn Engine over (was told starter needed one-way bearing, false, bad cell in battery, needed new battery)

New battery turns new starter over, (now have 2 new starters, one on buggy both tested ok).

Fried the green wire on original stator, replaced stator, buggy ran like a "raped ape", reached an average of 61 mph on 4 full WOT (Wide Open Throttle) passes (ran out of road never reaching top speed)

Now I'm getting excited until it fried original coil, no spark at coil or plug, replaced coil, again ran like a "raped ape" (love that saying lol)

Fried second coil, (think I broke my toe, new ding in front rim)

Replaced with high performance coil.
Again ran like a... you guessed it, a "raped ape."

Fried second coil. (No kicking this time, toe healing nicely, still have dent in front rim as a reminder)

Now I'm testing everything again and again while/as I'm replacing the fried shit. If I NEVER see an ohm meter again it will be too soon.

Bought 2 more performance coils and an oem one. (they were cheap on ebay).

I found all fried electronics via ohm testing.

Due to others recommendations in repairing this mystery and so I could rule those parts out as a possible cause. I've replaced the CDI (Capacitor Discharge Ignition) as well as pulse generator/rectifier. "NEW" not used, even though originals tested fine.

Took a few days off due to dwindling bank account and my sudden urge to burn this bitch to the ground and swim in the ashes.

Currently all electronics have been replaced, twice (yes, all new stuff tested and in working order).

Now I'm going to add a another ground wire (like the green one in Lanix's pic thanks Lanix) from the Engine mount to the frame (that's the wire I had suspected was missing and what I now think was the root of my problem all along).

So sometime during the week I'll get to this and let you guys know if it worked.

I want to thank "Canadian Oddy" for poking his nose back in this forum and getting the ball rolling on this adventure and for helping me find "adnoh" who busted this mystery wide open.
(Starts humming the Scooby Doo theme song?)

I feel like a ton of bricks has been lifted off my shoulders.
Thanks guys

And thanks to all those who commented and at least tried to diagnose what it could have been without even seeing pics.

I'll be sure to pass on all I've learned from this so others don't have to go bald pulling their hair out.
(In case you wondering, hair is growing back nicely)

Ride safe, wear your helmet and your seat belts and no driving over cliffs.
(Looks over at Canadian Oddy with that "you know what I'm talking about look")

Peace my brothers and thanks again.
CB

PS: I'm not really going anywhere as I have, will have, a gazillion questions as I upgrade this buggy. So you old farts pop in every now and again and help a brother out.

PEACE!!
(Holds up the Vulcan gangster live long and prosper hand sign) that's right I'm gangster like that.

Adnoh is our resident electrical guy (propeller head).
He don't show up very often anymore either but knows his electrical stuff.
Don't be cheap on the size of that ground wire ---- adnoh did comment on that.
Make sure the ground connection area is scraped clean. There is always rust and corrosion in that area of an oddy.
Hopefully you'll have some fun now. Word of caution: At top speed the oddy is very twitchy. If something goes wrong just remember these things do highway speed. Lots of people get killed on the highway. I got close with my helicopter ride.
CO