YTM200E cutting out at full throttle under load

[dz]

Well, where do I begin. I found my YTM200e under somebody's deck, been there for years and years. Entire fuel system jammed up. Cleaned petcock, flushed gas tank with new gas, put on a newer working carburetor, put in a new air filter and changed the oil. Engine fired right up without a hiccup, let it warm up and got the oil flowing, ran extremely well with no smoke. Rode it around my yard for a bit, with the intention of changing the oil and rear fluid once warmed up and moved around a bit. After about 20 minutes there was a little cough from the carburetor and she sputtered and died. Started her back up and all seemed well, but an increasing problem arouse. Under load approaching full throttle the bike would severely sputter and if more throttle is applied the bike just dies like it lost spark or its will to live. If you cut back on the throttle she comes to life. I've tried adjusting/re-cleaing the carburetor to no avail. I took the fuel cap off, no difference. I disconnected the fuel line from the carburetor to check fuel flow, it flows freely and fine. I disconnected both the key switch and handlebar stop switch thinking it may be electrical with no change. I changed the spark plug coil with no change. I changed the spark plug with no change. I sprayed contact cleaner around the carburetor intake looking for an air leak, but no change. Anybody else have this type of problem before? Why all of a sudden would it hiccup and run crappy now? Could I be looking at a CDI or trigger coil problem? Any help would be greatly appreciated, really looking foreword to taking her out on the trail.

[muthey]

I have ran into this a couple of times, one the main needle is moving in the slide, or two your bowl isn't filling fast enough, which means the float level is wrong, or it is flooding out into your air filter and motor, which in turn the o-ring that goes to the float needle seat is shot or the float needle itself is shot, I know it sounds like a lot but it all mainly boils down to the carb, check the main jet for debris, a hair in there can give you some issues as well.

[dz]

Well, I've tried another needle/slide combo with the same result. It doesn't seem to be flooding, no gas in air box and no black smoke. It rev's up fine no load, but under load it just dies.

[dz]

Forgot to mention the main jet is clear, I can hold it up to some light and see through it.

[muthey]

take a piece of wire and go through all of the holes at the back end of the carb there was a guy on here that had debris in them that kept cutting out his throttle from it

[code-blue]

I had this problem with my 1985 225DR, my float bowl wasn't filling up fast enough under WOT, it would sputter and almost die unless I backed off. Try setting the float level. Good luck.

[dz]

code-blue,
whats weird about the problem is that it was running perfectly fine for 20 minutes with the current setup. It just kinda backfired through the carb. and then developed this problem. I'm still wondering about an air leak. When I moved the main needle up to run richer it seemed to run a little better.

[muthey]

have you tried a new spark plug possibly a hotter one as well, I know you said it's not smoking, but have you tried a compression test yet? On top of all that what is the actual part number on the carb you put on? it does make a difference, it can be found on the top of the intake mounting face, might have the wrong jets in it?

[dz]

Well, here is an update and hopefully someone could chime in. I've tried another known working CDI with the same results. I've tried another spark plug boot with the same results. I've tried yet another spark plug with the same results. I hooked up an auxiliary gas tank with different fuel with the same results. I've looked at the timing and it's spot on. I've installed a new carburetor intake boot and new o-rings with the same results. I've re-cleaned the carb. with the same results. After all that its still sputtering past 1/2 throttle. I know it's screaming main jet but after all I've done I don't think it can be. I tried re-adjusting the carb. raising the needle all the way and lowering the needle all the way with the same results (although I looked at the exhaust and no matter which direction I move the needle the exhaust is smoking black like it's burning rich while it's sputtering or it's losing spark). It starts right up when cold with no hesitation up to 1/2 throttle even under load. It did not have this problem when I first intsalled the carb. and ran fine for almost a half hour with no problem at all. Could this be a sign of a weak pickup coil that picks up the flywheel magnets? I really don't know what else to try, valves are adjusted properly too. Running out of ideas. Any help would be appreciated.

[dz]

Also, while I had the carb. apart I installed a new o-ring that goes into the needle pickup tube, and that didn't change anything either.

[muthey]

run it for awhile and check your oil I am starting to wounder about your valve seals as well, even with properly adjusted valve, bad seals will cause it to smoke. so many possibilities check your pickup coil then after that you might have to open the top end even as much as I hate to say it, but something is just not working right. But check the coil first as that is alot easier to check then the top end. After that all I can say is there is a starter jet in the bowl of the carb make sure that is clean and that your choke is working properly and has the right o-ring. would be awesome if it was just something with the choke so double check and double check, before tearing into a motor. The one thing that concerns me the most is the backfire through the carb as you described it.

[tri again]

Sounds like you did the carb to death altho,
I've done the same carb a couple times and found a
clog on the 3rd time through.
Very frustrating for sure.
Just because the jets are clear or new doesn't mean the internal passages are clear.

Blow thru them under water with a piece of fuel line and look for bubbles.
Heck, I've even boiled a few of mine in water with vinegar and lemon juice.
Amazing where crud can hide.

Is there any chance the exhaust plugged itself somehow?
Baffle came loose?
Is the compression good?
valve hanging open?

Try nipping the last tiny bit of the plug wire so the cap has some new wire to bite into.
Free and fast and I've seen that cause days of headaches.
or take the cap off altogether and use a piece of copper wire.

Signal breakdown?
Check all your frame and wiring grounds, esp coil to frame mount.

It may be failing at the higher revs simply because of a weak connection.

I even had an air filter that looked NEW but was plugged with the finest dust on the planet and would NOT pass air.

..and finally, here's my fav chart, but prob has nothing to do
with your issue.

Good luck.
You'll get it.

[El Camexican]

Sounds like something is cutting off air. Bad valve seals won't make it do what its doing, DON'T open the engine!. Make sure your air box isn't full of water from the last wash and that there isn't something obstructing the air filter or anything else air tract related. Too much oil in the filter can do this as well.

[dz]

Camexican, It's a brand new air filter and I even removed the air filter and it did not change anything. I've never been able to wash it because after I got it running it only ran for 20 minutes or so so it really didn't get dirty.

Drjoe171, I've isoltaed everything except what was needed to make it run with the same results. I've disconnected everything and looked at every connection, every connection was clean. I even tried jiggling the wire harness with it running and that didn't change anything either. Today I am going to look at what color the spark is, I forgot to do that yesterday and probably make a video of what it is doing so you guys can see what I am talking about. I had my buddy looking at the spark while I was cranking it over and he said it looked orange which could signify a problem. Exhaust is pretty much free flowing at this point, the baffle end was rusted pretty bad and on the first start after I put it all back together it pretty much just blew out.

Muthey, It's not blue smoke it black smoke when it starts coughing. It sounds like somebody is turning the kill switch on and off real fast, not bogging down like too little or too much fuel.

[muthey]

ok I'm starting to think it is electrical, and not fuel related at all. You can check the pickup coil with out tearing into the motor, the repair manual has instructions in it, and can you see any spot where the wiring might have been repaired or replaced at any time, ie: lots of black tape. There should be a fuse in the wiring it make look good but for the price just replace it anyways, have had far too many that were old and looked good actually turn out to be my culprit. And like drjoe said go through all the grounds again take a piece of sand paper or emery paper to them all to ensure a clean connection. Have you opened up your kill/light switch to see if there is anything in there that could be messed up that might start moving under higher vibrations? Lift tank and unplug keyed ignition, and start it see if that is the culprit, maybe there is a loose connection in there wiring is a real pain at times but not hopless

[El Camexican]

Ok, now I'm on a computer I can type on. Process of elimination:
You say it did run well at the start, so that’s a great thing
Its smoking black, excess fuel is the ONLY thing that can cause that, but that does not necessarily mean you are getting more fuel than normal, just too much fuel for all combined conditions. You've eliminated the clogged air filter theory, but if your model is like my 83 YTM it breathes through the backbone tube of the frame. You said it was parked a long time, so there could be a wasp nest in there of a small family of raccoons, check that out. Before you say it, yes I did see you tried running it without the air filter, but these engines don't like to run unfiltered and will die out as yours is without the filter, but there would be no black smoke if all else was copasetic. So with good air flow determined and, a highly likely mechanically sound engine you are left with only electronics and carburetion. Given your carb tinkering so far and your last comment about the on/off symptoms leave the carb for now and focus on the electronics (unfortunately my Achilles heal) It does run, so turn the headlight on and rev it as much as you can. If brightens a lot and is not some puke yellow color at high revs that tells me you are making all the electricity you need to run the beast. If it flickers off and on we are on to something. Note: It will be very dim and yellow at idle, that’s normal. At that point I’d start tracing wires starting at the alternator/generator/magneto where it first connects just above the chain/shaft (Keep in mind I’m still talking 83 YTM 200K). Pull it apart, check for half cut wires, loose connections, corrosion, etc. Repair any flaws and spray it with dielectric grease before assembling. NOTE: After working on each connection start the trike again to make sure you did it right. One change, one test, no exceptions. If you jack with 10 different connections and then trike won’t fire at all you’ll end up slitting your wrists and mentioning me in the suicide letter! Keep advancing on the wires and pay carful attention to the grounds. Pull the bolts, remove corrosion and replace them. Check the cables where they connect to the eyelets as well. I’ve seen a two year old Ducati die on the road from a loose ground connection. I don’t know if your model has a key, or just a kill switch, but if you make it all the way to there without finding a problem this may be it. Look close for anything less than perfect, including loose wires that could touch while vibrating. Regardless of whether or not this fixes the problem check the color of your spark again, but pull hard and fast as I think the spark plug is like the headlight; weak at low RPM. Make sure your gap is no more that .028”. Now if all this still does not work you are heading back to the carb (don’t feel bad, you still will have ensured future reliability in your toy) Ok, first stop is the choke. Make sure the lever/cable is allowing it to close. I think the cable tension is adjustable. If it is closing fine pull the carb off the engine and take a good hard look at the rubber intake tract. I cracked one once and it was sealing at low RPM and vibraiting enough to let air in at revs. Lots of popping and backfiring, but no black smoke. If that checks out get to a clean bench, sweep the floor around you and surround yourself with small empty plastic containers, or egg cartons to store parts. Remove the choke piston and check that the O-Ring is in perfect condition and that there is no crud in the hole. Q-Tips work great, but you have to spray carb cleaner in after to blow out the “fuzz”. Put a dab of Vaseline on the O-ring before you put it back together and make sure it feels like there is resistance, or suction as it moves up and down in the bore. This is a must! Now pull the bowl. Wipe it with a clean white cloth and look for anything and I mean ANYTHING. I had an RD350 that would die at the most inopportune times and it ended up being what looked like a small piece of steel wool that found find its way into the main jet and coiled up under load. I couldn’t even see it the first time I looked in there! Anyway, if at some point you used anything inappropriate to clean the holes in the jets now is the time to admit it. If you saw so much as one speck of brass as you were cleaning the orifices you need to replace that component. Make sure you are not missing and small jets. That would cause all kinds of hell and black smoke. Pull the all the jets and carefully clean out all the small holes (if this has not already been done). Now take a good look at the inside of the tube that the main jet screws into. I’m blessed with nearsightedness, so if your not find someone who is and ask them to look for scuffing, or any signs that it might be oval in shape, it has to be smooth and round up at the top where it enters the intake tract. I think there is supposed to be a small piece of plastic in there as well, make sure yours has it. Look at th eneedle jet where fuel enters. Put a hose on there and simulate light pressure by blowing into it (yes BLOW, don’t suck, it totally different!) while moving the floates up and down to see that you are getting a seal before the floats contact the body of the carb. I don’t recall seeing any thing about leaking fuel, but if this is an issue you should have seem some while it was either running or parked. Put it all back together, set the air screw at 1-1/2 turns, put the needle clip back in the middle and check the gasket on the cap for any signs of imperfection. You can play with the air screw and idle speed as soon as you start the trike, but leave that needle clip in the middle until the motor is working. Playing with that is part of fine tuning, not a fix. Note: raising the needle by lowering the clip richens and lowering the needle by raising the clip leans) And what about that needle? I think you said you changed carbs, did you change out the needle too, or just the carb body? Regardless, take a good look at it and make sure its smooth and round and that no rocket surgeon cut the tip off it. If after all this it does not run correctly the only thing left is the power source itself which I think is a magneto (at least on mine it is) They can be checked, but I’m not the guy to tell you how. One last thing. Was there any indication that someone was messing with this thing before it was parked? i.e. dents or hammer marks on the float bowl, or messed up float bowl screws? Good luck!

[dz]

Elcamexican,
Good info. I have checked every connection on my wiring, and pulled every connection apart to double verify everything was at least looking ok. I've gone with my gut feeling and pulled the carb. off again. It is now soaking in some mild vinegar water, and later tonight I will probably boil it and hopefully it will dislodge whatever may have gotten stuck in there. It looks as though the bike was never messed with. The original carb. that was on it was destroyed, the gas was so bad it started eating away at the aluminum and brass jets. My head light is good when rev'd up. I cleaned a spot on the head to make good contact and checked the spark again, its nice and blue. It looks and when it ran good felt like a low hour machine. I can't find my compression checker at the moment to check compression but it feels decent to say the least.

[muthey]

hey dz you know just out of the blue did you guys pull and clean the fuel tank at all or replace fuel lines? Just maybe it isn't in the carb but something inhibiting fuel in your tank from filling the bowl up at the right rate?

[Tuff]

sounds like a float level issue or a worn out needle/seat. also you said you checked for air leaks with contact cleaner-NFG. use carb cleaner to check for air leaks. spray the intake and the carb itself. I had a sled of mine that had a crack in the carb itself. if you find a leak the engine will pick up rpm's when you spray it..

[Headsup]

Also u said its not the original carb. Could be one of them Cheap O Carbs thats Storming All over the internet, And Even i know they cause hellish problems. Even when Everything is brand new, What your Jet Number says May not be the actual size.
Also u never know what all it went threw prior. I would Look into that sucker. Should have a part number on it.

Anyway nothing much else to say after every1.
just wondering what could have Happened to Maybe the Throttle Needle when it Backfired threw the carb Maybe Got a little bent or something?
Maybe it blew air Really hard into the float Chamber and Messed up the Float Settings. Which that would not be something you would just be able to see with your own 2 eyes.
Idk Much but i Try threw my Experience.
i know u said it hard to get the manual, But maybe try to Go somewhere and print it out. Its a Ton of New Information everytime u read it i think. I would have been Lost without it, Diagrams right down to Troubleshooting

[code-blue]

Hello dz,
I ran across the same problem you have. When I took my carb apart to clean it, I forgot to reinstall the spring that goes on the pilot screw. When the engine was running, it would let the pilot screw back out a couple of turns making my DR 225 run lean. I think you have the same problem. I took my carb apart so many times, I over looked the missing spring. Like you said it would pop and sputter like it was losing spark. Good Luck, Timothy