Does this seem like a fueling issue? *video included*
 

It just started doing this the other day, it would cut out mostly at slow speeds modulating small amounts of throttle or when giving it a fistful. At first it seemed like an electrical issue but after watching the video it seems more like a fueling issue...

I had some odd misses a couple weeks ago after I lost the front tire on some debris, but when I replaced the old coil it seemed to fix it (it ran like crap in pouring rain). Maybe it was just gunk floating around? I have noticed that the cold start in the morning has been more difficult. With full choke out it would run for a few seconds and then die, but would be okay after the second time. It used to start on the first try no matter what until recently. Also, if I stop at the gas station in the morning I would need to give it throttle to restart. The valves should be okay but I need to check them this weekend.

http://youtu.be/i-HxGe8qcIg

The first clip was going to work, the rest are after I tried riding home. After I got off the freeway it backfired once and seemed okay again when I got back to work.

Clean carb. Specially remember to check filter inside.

Certainly seems like a fuel issue :(
Clean carb, check if fuel tap has a vacuum line & check for a leak, then I would remove fuel tank, turn it upside down to drain & flush also.
It could be some junk from the fuel station doh

strip and clean fuel tap as well.

Ughh this bike...

I took off the carbs last weekend, the float bowl filter was clean except for two tiny little black dots of something. The main jet was spotless, no clogs in any of the tiny holes. Overall the carb was very clean inside but I sprayed every nook and cranny multiple times. The carb boots are okay, on one the front lip has a tear from taking the carbs out multiple times (the mating surface from the carb/boot is fine though). I cleaned the over run valve as well. Valves are in spec. I cranked it over and it started immediately, and it ran better then it ever has.

I rode the bike all week and it ran and idled perfectly. I was pulling up to work today and when I stopped behind a car it died and refused to start. After I pushed it back into the warehouse and let it sit for a while, it started after cranking and using the throttle. Idle seemed fine but as soon as I gave it any throttle it died. I got it running again and it idled for a few minutes before sputtering out.

It STILL seems like a fueling issue. What the hell is constantly blocking fuel flow???? I have an Acerbis tank with twin petcocks so it's unlikely they both are clogged up (they flow fine if I just remove the hose). I adjusted the float a little but it ran all week and a few hundred miles before crapping out again. I swear I'm THIS close to buying another commuter bike this weekend. I need a bike that is 100% reliable and trustworthy, my commute is way too dangerous to do it on a bike that can die randomly. It's been fine for 30K miles, why now??? ARGGG

It's electrical probably, unless the pilot circuit isn't actually clean, but that should act up constantly not just random.

something is clogging a jet. When you cleaned it it cleared up . After you ran it a while you went back to a fuel problem. Are you using a fuel filter? I had a problem like that and found that my old fuel like was crumbling a little every time I pulled it off and on and was clogging the jets I just clean. Also check the rubber on the under side of the fuel cap. The one on my clark tank was crumbing from age and dropping black bits into the fuel. THUMPTHUMP

I'm not running a fuel filter at the moment, I had some bad experiences with a high flow inline filter on my old bike. Maybe I should put one in anyway.

It doesn't seem to be an electrical issue, when the engine dies it feels more like a lack of fuel. I got it running later that afternoon and at first it would only start (after cranking for a while) with the choke fully on, and when any throttle was given it would die. With the choke on I could rev without issue. After a while it seemed to be warmed up enough to rev without the choke, would idle perfectly but would sputter out after a minute or two.

I drained the float bowl after it died and also just removed the screw with the petcocks on, and the bowl was full of fuel. Even though it seems to be starving of fuel there was plenty of flow.

This seems to be an ongoing issue, before it started dying I had two times when riding around town that it would give the feeling of running out of fuel. The tank was more than half full and it would give the same symptoms of being low on gas before turning on reserve. It passed after a few seconds though so I kind of mentally wrote it off.

I ordered some new boots, the ones on there are kind of ratty (one has a tear on the very outside surface but doesn't effect the mating surface). When I first reinstalled the carbs the edge folded over some causing a big air leak. Before I fixed that it had the similar hard to start and dying issue (felt different though), I reseated the carb and tightened down the clamps and it was fine for a while. It seems strange that it would suddenly cause an issue again if it was that.

I guess the plan of attack is do a really good cleaning (soaking in Berrymans), spray with carb cleaner and compressed air, replace the boots and any old fuel line. The Acerbis petcocks look clean but I'll check those as well.

Someone on ADV rider suggested that the issue may be the CDI unit. I've been doing some research and the symptoms of a dying CDI match mine almost perfectly... I'll try cutting mine open and reflowing the solder this weekend and give some updates here.

Did you ever find a solution for this issue?

Not yet, I haven't had the time to tear it apart yet.

I watched the videos in your thread btw, I have been getting the little stutters while idling too for a long time now. My bike also dies out now just like in your video. Ugh. I'll take a look at the enrichener circuit too, I remember cleaning that out some because it was a bit dirty. Maybe the washer on mine is backwards as well?

I had some time to work yesterday and tried to start the bike before taking off the carbs. It wouldn't start at first (cranking slowly, the battery was a bit low) so I gave the TCI quick tap with a wrench... After that it started up immediately after hitting the starter button again.

I have the carbs torn apart, might as well clean them to be sure but I also took out the TCI. Looking under a bright light I can see what looks like two dry joints on the board. They aren't nearly as bad as some examples on Google but there is a very faint circle around the post on at least two soldering points. I dragged the tip of a sharp knife on it and I can definitely feel an edge on there.

They look fairly minor but that could definitely be why it would run for days without issue before crapping out. I'm working for the next 7 days so hopefully I can reflow that solder and test it out next weekend.

Edit: there are a few other joints where I can see cracks starting to form. They look like very light circles (a few half circles) around the post. There's maybe 5 of them and one that is for sure bad.

That's how Honda XR cdi's fail also(same symptoms) . Common fix is hitting all the points with a hot iron to reconnect them then filling the case with epoxy. The solder the Japanese used must be fairly brittle and too little applied for longevity. Could very well be the same company that makes them both .

Iam no fan off filling them up with epoxy, thats the last time you fixed it if you do. Redo the bad spots and check the box once a year.

So it's still not fixed :thumbdown:. I installed the new boots, sprayed the carb, hit it with compressed air and reflowed the questionable joints on the TCI. The bike fired right up on the first crank and was running great. I test rode it around the neighborhood, ran it full throttle through fourth gear and then let it idle for a few minutes in a nearby parking lot.

I took off to go around again and when I left a stop sign the engine just died. It's not a stumble like fuel, it just shuts off instantly. It restarted with the button, tried to roll on the throttle and it cut out, backfired loudly and went back to idling. Every time I would use more then 5% throttle it would cut out dead for a split second and then catch if I let off.

So it's definitely an electrical issue... It can't be the carbs, it ran great until it was hot, if it was the float level it would have given me issues from the start, same with the jetting.

I doubt it's a wiring harness issue, I've jiggled it before and did nothing. So it's either the TCI is still bad, the coil (I'll try replacing with the old one), plug wire/boot or the plug (which looks fine). Is there a pulse generator or something under the cover with the stator? I'm running out of things to check...