starting/running problem

[timsatx]

I have never seen this problem until this week. Starting and driving in the morning is not a problem. The afternoon is where the problem has occurred. When I get out from work I start the bike, after a minute or so I take off. The bike then acts like it has a fuel starvation problem. It would just shut down like it ran out of fuel.

I mange to get it pulled over, play around with the choke and starting it up and finally it works. That was the first two times. The last time it was a bit more of a problem. I even turn the petcock to prime and it didn't fix it. Then I opened up the gas cap to see if I could hear fuel sloshing around ( had already gone on reserve) but was unable to with the helmet on. Closed it up and tried starting it with the petcock still on prime. Got it started and it seemed to run fine, same as the other times. What do you think it could be?

[snarf]

How often do you run your tank that low?  You could have contaminates in your fuel.  Does the bike run better on a full tank?

[cmoore]

Does it do that with a full tank as well? It sounds like the fuel cap is clogged. Mine has done that a few times in hot weather when the tank is run down close to reserve.

[timsatx]

In the 1.5 years that I have had the bike I pretty much always run it to the reserve before I fill up. The only time I don't is when I know I am going for a ride. When it started I was still about 70 miles away from reserve. I won't know about it doing it when full until I can fill it up which will be about Wednesday next week unless I get a sudden infusion of cash. Again though, it only does it in the afternoon when it is one hot mother, never in the morning.

[thundercloud]

Mine acted like it was out of gas yesterday. I started it put on my helmet and pulled onto the street and it started to stall.I hit the chock briefly and it was fine.I had riden it to work and it sat in the sun all day [heat index of 107] ran fine the rest of the way home and this morning. I'll see what it does after work.

[Summit670]

If there is a fuel filter between the petcock and carbs this can cause no fuel when tank is low, esp when it runs out of fuel and it is switched to reserve.  Then when it is on reserve there might not be enough pressure to keep fuel flowing due to low fuel.

[timsatx]

No fuel filter on mine. I have heard of too many people having too many problems related to fuel filters.

Mine acted like it was out of gas yesterday. I started it put on my helmet and pulled onto the street and it started to stall.I hit the chock briefly and it was fine.I had riden it to work and it sat in the sun all day [heat index of 107] ran fine the rest of the way home and this morning. I'll see what it does after work.

Very similar to what mine is doing.

[thundercloud]

Just rode home.Temp is 101 actual degree right now, ran fine,but I did not leave it in the sun all day.

[SteveJ.]

Definitely an issue there. I ran my bike low enough to take 7.1 gallons on the last fill. It has a "not new" Napa 3006 filter on it. It's hot here. FWIW, had the bike on the dyno for our dyno party back in Feb. The temp in the trailer was 94*. I had no issues with fuel starvation during my session of three hard pulls. No change in air/fuel ratio at all. This would lead me to believe that folks that are having problems with extra fuel filters should be looking elsewhere for the problem.

Just my anecdotal evidence.

[timsatx]

The problem with me isn't after I have it running, it is getting it running in the first place. After I take care of the hiccup it runs great. I will see what it does when I leave in a few minutes. It is currently 99°.

[Summit670]

I'd try draining the carbs to see what comes out.  Easy to see by putting fuel in white cup.

I'd check the in-tank filter to make sure it isn't plugged.  May be able to see with a small mirror and light, look in there at night with lights off. 

Check the vacuum hoses.  Esp the one going to petcock.

Make sure petcock flows fuel in prime position.

Oh, check the main fuel line for kinks or too much extra length which could cause kinks.  If it happens in really hot temps that maybe the hose is kinking and the bike would run fine for a little while.  You drive it giving it a chance to cool but by then you are out of fuel.  after you stop a while the fuel has a chance to run thru the hose enough to cool the hose down.  Sounds logical anyway.

[timsatx]

It happened again yesterday after work.  I can check all those things but what gets me is it only happens in the afternoon after sitting in the heat, never in the morning. It does make me think that it is either a petcock or vacuum problem. When I went to prime it took care of it, then when I switched back it would happen again. First I am going to check the vacuum lines and see if that is the culprit. Anybody ever take their petcock apart just for cleaning?

[Summit670]

ck the vacuum line to petcock

I've had mine apart a few times, once to stretch the little springy a  little and another time to install a new diaphragm.  Easy to do.  Just drain you fuel tank first.

While you are at it, may as well pull petcock from tank and make sure the filter is clean.  Just be careful pulling the petcock out of the tank.  The filter comes with it and is a snug fit.

For the valve seat, you should make sure that is clean too.  Use a Q tip or something.

Jim

[m hanlen]

It happened again yesterday after work.  I can check all those things but what gets me is it only happens in the afternoon after sitting in the heat, never in the morning. It does make me think that it is either a petcock or vacuum problem. When I went to prime it took care of it, then when I switched back it would happen again. First I am going to check the vacuum lines and see if that is the culprit. Anybody ever take their petcock apart just for cleaning?

I think it's a vacuum problem also but I'm thinking your slide in #2 is sticking because of varnish. A little carb cleaner in the air filter without the filter and engine running might cure it if the vacuum hose or petcock isn't the problem.

[timsatx]

Computer at home is SNAFU so I was unable to post this weekend. I pulled the tank and looked at the hose, it looks almost brand new so I did not see a problem there. Pulled the petcock out and the filter looked very clean so no problem there. Took apart the petcock and everything also looked fine in there. I did give the spring a little pull as I have seen recommended.

The only place that looked like a problem was the air filter. I cleaned it a year ago or so but it had to be the worst looking filter I have ever seen. The damn thing was filthy. I cleaned it up and lubed it again and this morning drove it to work. I will find out this afternoon if that does anything for it. I will let you know tomorrow (since my computer is SNAFU).

[timsatx]

Everything worked okay last night. I think that the culprit was the dirty Air Filer. Not know exactly how the carbs work I would say that the clogged filter was preventing air flow which contributed to the lack of vacuum. I will keep an eye on it the next couple of days but I feel certain that it took care of the problem

[m hanlen]

Everything worked okay last night. I think that the culprit was the dirty Air Filer. Not know exactly how the carbs work I would say that the clogged filter was preventing air flow which contributed to the lack of vacuum. I will keep an eye on it the next couple of days but I feel certain that it took care of the problem

Since we haven't heard from you, it must be working fine. A clogged air filter will increase vacuum by restricting air flow. I don't know how that would only be a afternoon problem. Inquiring minds want to know!

[Curtiswesner]

I have experienced this a few time during the warmer periods of the year. My theory is that sitting in the hot sun builds a little pressure in the tank, and when you take off the high pressure in the gas tank won't allow for the vacuum actuated fuel valve to open, till you open cap or jostling of bike releases some pressure. I have learned to either open tank or just let her warm up a little longer in the parking lot while putting on my helmet, gloves, etc.

[timsatx]

Yeah, sorry about that. I haven't had any problems since I cleaned the air filter. Whether it was simply going over the petcock was it or the filter, I don't know, but it is working fine now. One thin I just started doing yesterday was to find this one little area with shade and parked the bike there. I am generally at work 45 min. to an hour before most folks so I usually get the best parking spot. Monday after work when I left for the gym the whole bike was hotter'n hell. The tank was super hot, as was everything else. After parking it in the shade for the day it was much more comfortable getting on it yesterday. And the pressure in the tank thing doesn't surprise me. One of the times I got it running was after I opened the gas cap.