Hard starting when hot.

[Outlander]

1980 GS550E. Carbs completely rebuilt per forum tuturial. New O-rings all the way around. Engine fires on all 4 cylinders. Starts fine cold. After I ride her for a bit, I come to a stop, she idles around 1100 no problem. No fluctuation. Valves are within specs, floats are normal. Yet if I go to start her afterwards, even a short while, she has a hard time starting. I have to apply a bit of throttle for her to start. Is that normal? She use to start without having to apply throttle. Plugs are fine, nice color, no fouling.

Any suggestions?

[TheCafeKid]

Hrmm. I would check a couple of things. Hows your battery? Charging well? And is it holding a charge? Secondly, you may actually be having a problem with your petcock and/or float valves. If either of these are not holding back the fuel as they are supposed to, you may be flooding a bit. Now when you say hard starting, is it just spinning and not firing? Or is it having trouble cranking? What exactly is it doing?

[Scotts]

Mine does that some as well. I am still getting used to mine. I have put about 600 miles on it since getting it. Mine is an 86 550 es. I'll give her about 1/2 to 3/4 choke and hit the button and quickly put the choke off. It fires right up and we are on our way. If I don't use the choke I have to give it a shot with the throttle and it cranks a little longer than I want it to until it starts. Mine acts much the same as you describe yours on the cold side.

Oh the joys of the motorcycle! It's a beautiful thing.

Scott

[Outlander]

Hrmm. I would check a couple of things. Hows your battery? Charging well? And is it holding a charge? Secondly, you may actually be having a problem with your petcock and/or float valves. If either of these are not holding back the fuel as they are supposed to, you may be flooding a bit. Now when you say hard starting, is it just spinning and not firing? Or is it having trouble cranking? What exactly is it doing?

My battery and charging system is fine. New battery, and my charging system is up to par. I do not see any bleeding of electricity from the battery. My petcock has not been replaced....yet, however, it is functioning okay. I am not noticing any gas in my crankcase. My floats have all been redone, and set. New seats and valves have been installed. When I try starting her when she is hot, she spins over just fine, wants to fire, but doesn't. When I open the throttle just a little, she catches and runs. I rev the bike a few seconds, and then she idles normally. I suspected some type of flooding as well. All hose clamps are tight, and no rips or tears in either manifold boots or air intake.

Could it be do to lack of back pressure? I didn't think that was needed to start a bike, but I could be mistaken.....

[TheCafeKid]

My battery and charging system is fine. New battery, and my charging system is up to par. I do not see any bleeding of electricity from the battery. My petcock has not been replaced....yet, however, it is functioning okay. I am not noticing any gas in my crankcase. My floats have all been redone, and set. New seats and valves have been installed. When I try starting her when she is hot, she spins over just fine, wants to fire, but doesn't. When I open the throttle just a little, she catches and runs. I rev the bike a few seconds, and then she idles normally. I suspected some type of flooding as well. All hose clamps are tight, and no rips or tears in either manifold boots or air intake.

Could it be do to lack of back pressure? I didn't think that was needed to start a bike, but I could be mistaken.....

Well, is the pipe stock? or something else? If its something else did you rejet for it at all? And how does it start on choke?

[Calvin Blackmore]

I used to get hard starting while hot on hot hot summer days
it was almost as if the remaing fuel in the bowls was evaporating

maybe you should set to prime for hot starts?

[Hap Call]

As long as it is certain that it is not an issue of low compression, it really should not be a problem. It is my guess that you are a little lean due to EPA jetting...Just give it a little choke each time but try not to grind the starter.

Hap

[Outlander]

The pipes are stock, I just drilled them out a bit. Nothing substantial. Starts fine cold with the choke. There was a large hole in the center of my exhaust, followed by a small hole at the 12 and 6 o'clock position. I drilled the two smaller holes out to 3/8 and then added 2 more at the 3 and 9 o'clock positions. Gives the bike a nice deep rumble, without being loud like a harley or honda running straight pipes.

Stock jetting, did not mess with them. Only my pilot air screw is at 155 instead of 150. All the rest of the jets are stock. I did not put the 155 jets in, it came that way.

Plugs are okay, maybe a tad rich, but nothing to write home to ma about. I turned my fuel/mixture screws in 1/2 turn just now.

If I turn up my idle screw, then the bike starts with just hitting the starter. But she idles then at 13 to 1500 rpms.

[Outlander]

Update:

After turning my fuel/mixture screws in 1/2 turn, and tightening some clamps, holding the airbox assembly, I found my problems disappeared. She runs better than she ever has, and I am estatic! I thought I had tightened the screws, but they backed off, so I put a lockwasher on them to make sure they don't rattle loose again.

I am amazed at the color of my plugs. I have never seen them this clean. I am in awe, as I never thought I could do it.

I have some things left that need to be done, but at least she runs.

[Steve]

Something has me puzzled.

I thought I had tightened the screws, but they backed off, so I put a lockwasher on them to make sure they don't rattle loose again.

What screws backed off? If it was the idle mixture screws, how the heck did you get lockwashers on them?
And, ... lockwashers only work when they are under compression, meaning the screws inside the lockwashers are tight. Idle mixture screws should not be tight.

.

[hikermikem]

After turning my fuel/mixture screws in 1/2 turn, and tightening some clamps, holding the airbox assembly, I found my problems disappeared. She runs better than she ever has, and I am estatic! I thought I had tightened the screws, but they backed off, so I put a lockwasher on them to make sure they don't rattle loose again.

I am amazed at the color of my plugs. I have never seen them this clean. I am in awe, as I never thought I could do it.

I have some things left that need to be done, but at least she runs.

I read his clamp airbox screws were loose, causing an air leak

[Outlander]

Something has me puzzled.
What screws backed off? If it was the idle mixture screws, how the heck did you get lockwashers on them?
And, ... lockwashers only work when they are under compression, meaning the screws inside the lockwashers are tight. Idle mixture screws should not be tight.

.

No, not the mixture screws, on the air intake boots, the screws on the old clamps turned out, so I put a lockwasher on those so they wouldn't back off again. Seems to work, as they flattened out. Keeping my fingers crossed.

On the mixture screws, I just turned them in 1/2 turn. Seems she was just a tad rich.

[TheCafeKid]

No, not the mixture screws, on the air intake boots, the screws on the old clamps turned out, so I put a lockwasher on those so they wouldn't back off again. Seems to work, as they flattened out. Keeping my fingers crossed.

On the mixture screws, I just turned them in 1/2 turn. Seems she was just a tad rich.

Likey due to the bump in the pilot jet. Generally you should nearly NEVER need to mess with pilot jets in size. Most pipes really require needle and main adjustment, so the holes you drilled in yours would certainly not warrant the bigger pilot. But, if you got it running well with them, then great! Just be aware of the potential of flooding/rich running down low with those larger pilots in there..

[wilmas2cool]

Same problem on our 1980 Goldwing GL1100 with no rebuilds. Then I discovered the gas cap was not venting. Tank built up pressure and had to add some throttle and a few seconds of cranking before startup. When I loosened gas cap and left off a gush of pressure it returned to instant startup. Checked our GS1100E and made sure gas cap was venting ok.