Every half hour my bike decides we need to take a break.

[yellowoctupus]

So, as the title says, about every half hour, my bikes starts sputtering and popping and eventually dies, at which point it won't restart. Eat a sandwich, let it cool down (15-20mins), and it runs great again. What's up??? I have a KLT200 (12V DC system with points). The only thing I can think is that the carb is vaporlocking on me, as the exhaust pipe on the early models is RIGHT below the carburetor. I didn't think to check the bowl to see if I could touch it when it was giving me problems, so I haven't tested that theory yet. Any other ideas?

I also put the condenser under the points cover, as it was convenient for wiring, but could that be getting too hot too?

Thanks

[R-N-D]

My buddy had a similar issue. Took the gas cap off, solved the problem for about 15-20 minutes and then did it again. Got a new gas cap, no more issues. Vapor lock.

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[82 250r]

Most fuel related problems turn out to be electrical.
I had a similar problem that was a stator that worked fine until it got hot and shorted out.

Check the stator and coil.

[yellowoctupus]

My buddy had a similar issue. Took the gas cap off, solved the problem for about 15-20 minutes and then did it again. Got a new gas cap, no more issues. Vapor lock.

So, I'm pretty sure I tried this when it konked out on me the first time. (That and I was checking to make sure I still HAD fuel left in there.)


Most fuel related problems turn out to be electrical.
I had a similar problem that was a stator that worked fine until it got hot and shorted out.

Check the stator and coil.

Stator shouldn't be a problem, as it's a battery fired coil, but the coil or condenser themselves, although new, could still be suspect. I need check for spark RIGHT when it dies on me next time.

[Trackburger]

I'd put my money on the gas cap as well.

My 250SX would idle great and ride good but when riding for about the same amount of time as yours (or shorter if I was riding faster) it would sputter and die out. The vent hole is most likely 90% plugged.... by sitting for 15-20 min it allows enough air to get in and equalize the pressure and allow fuel to flow again. I could literally hear the vacuum in the tank when it would die out and I vented the tank by cracking the cap open. New cap problem solved. If you don't have a full tank of gas leave the cap loose and ride around and I bet she runs fine.

[gimmeamidget]

Stator or plug cap faulty.

[yellowoctupus]

Ok, so to come clean, I don't even have a vented cap. I can change that though. Not to hard to make one. Again, I think I had opened the gas cap and it still wouldn't restart, but I DO need to make a vented cap sometime, so I'll do that before my next ride.


Stator or plug cap faulty.

Stator comment has been covered, it's a non issue here, as it's a 12VDC battery fired ignition. When you say "plug cap faulty", you actually mean the spark plug cap? I've never had a cap go bad. Can you explain further what you've seen as far as caps going bad?

[yellowoctupus]

Oh, and Trackburger, my dad and I have a '63 K-70-D as well. Sno-Traveler (http://people.clarkson.edu/~mitchepj/traveler.html)

[El Camexican]

Ok, so to come clean, I don't even have a vented cap. I can change that though. Not to hard to make one. Again, I think I had opened the gas cap and it still wouldn't restart, but I DO need to make a vented cap sometime, so I'll do that before my next ride.



Stator comment has been covered, it's a non issue here, as it's a 12VDC battery fired ignition. When you say "plug cap faulty", you actually mean the spark plug cap? I've never had a cap go bad. Can you explain further what you've seen as far as caps going bad?

It's very common for the copper wires that the cap screws into to fray, brake or corrode, but it wouldn't be something that works 30 minutes, stops and than comes back with regularity. Sounds like fuel tank vacuum to me.

[big specht]

Do you have another cdi? Try that I had a klt250 that did the same thing and it end up being a cdi

[yellowoctupus]

It's very common for the copper wires that the cap screws into to fray, brake or corrode, but it wouldn't be something that works 30 minutes, stops and than comes back with regularity.

Oh, yes, I've certainly seen that. Get nice spark when the plug is out, then as soon as you put it back into the cylinder it gets no spark. Yeah, a real fun one to diagnose. I have a NGK plug cap with a new coil/wire. And agreed, that failure is not a 30 min fix type of failure.


Do you have another cdi? Try that I had a klt250 that did the same thing and it end up being a cdi

Not a CDI bike. Points, Condenser, Battery, Coil.

[Dirtcrasher]

Did anyone say fuel flow??

Lots of these older petcocks have a filter thats plugged up; I rip them out and put in a clear inline fuel filter.

Fill your tank and put the carb feed hose in a container and use a timer on your smartphone. You may get 1 gallon every 6 minutes, I don't know.

The key is to see if the flow is a constant.

Just a suggestion.....

[Rob Canadian]

^100%

Rules out venting problems. Petcock, lines to the carb.

I would like to add make sure the gas cap is on while doing this test. See what the carb is getting.

[yellowoctupus]

So, I do have a snowmobile (inline) shutoff, as well as a snowmobile vacuum pulse fuel pump. It seems weird that the pump would/could be a cause of a problem, but it is in there.

Fuel flow goes--> Blitz Can Tank with welded in bung, 90° fitting, barb fitting, clear hose to shutoff, clear hose to fuel filter, clear hose to Mikuni Rectangular fuel pump, clear hose to carb. Lines show fuel in them, but I didn't check when it overheated/shut off on me.

Picture of the tank arrangement. It's not ideal, but there's nowhere else to run it. It's slightly above the carb, so it could gravity feed for most part, except up long hills. So far, it's ran fine up long hills, so I'm going to say that setup works ok. Kawasaki ran the tank below the seat and used a vacuum or electric pump to get fuel to the carb. Real wonky setup that I understand was only somewhat reliable.

Gas Tank Picture (http://www.3wheelerworld.com/attachment.php?attachmentid=235121&d=1474666056)

[Dirtcrasher]

Yup, that's the problem, :lol: J/K.....

[OZQUAD44]

Wow, that was not what I had in mind when I started reading this thread. Just goes to show, is always going to be hard to diagnose a problem with only a portion of the information.

That fuel can is not designed to breath, so unless you have a vent in the top of that tank somewhere your going to have the exact troubles your talking about. As the fuel drains from the tank there is no air going back into the tank replacing the space that was occupied by the used fuel, thus creating a low pressure inside the tank, and stopping the fuel flow.

I suspect, that since you have some alternate or suspect pump arrangement in the fuel line. That it will take some time for the fuel system to re prime the carburettor once it has run out of fuel.

To test this, go for a ride and wait for the bike to stop running. As soon as this happens, take the fuel cap off the tank. You will find that the fuel cap is a little hard to remove, and that you will hear the audible sound of the vacuum being released as you get the cap open.








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[yellowoctupus]

Wow, that was not what I had in mind when I started reading this thread. Just goes to show, is always going to be hard to diagnose a problem with only a portion of the information.

So I SOMEWHAT tried to leave that out at first, to make sure everybody didn't immediately jump on the gas tank solution (as I'm not sold that's the problem, I'm 95% sure I DID take the cap off to check the fuel the first time this happened, with no 'sucking burp of air' in or it restarting any quicker). Sorry for being ... misleading... :banned:

One of the reasons I haven't reported back yet with results is that I've been riding by myself on a bike that has reliability issues, so if it dies, I'm stuck somewhere in the woods, with my fingers crossed I can get it started and get back home. So be patient, I'll gather up the gumption to do another solo ride, eventually.