hard to start - bad gas or fuel pump?

I have a 2008 250R. Build date 2/08. Bought used from independent dealer in Feb. He "said" the fuel pump had been replaced. At that time I did not know what he was talking about, but he mentioned the 2008's had pump problems. Bike had less than 300 miles then, and now has 592. Has run flawless. I have done the airbox flapper mod, and removed the AIS. Programmer coming soon. Stock exhaust. Still runs flawless.....until today.

Went to trails with normal buddy....he has Kawasaki 250 2 stoke. We filled up with gas near the trailhead. Unloaded the bikes and mine fired right up as usual....so did his. As soon as I gave it some throttle it died. Then it just turned over & over without firing. Seemed like a lack of fuel or spark or both. Got the tools out and went all the way down to check the spark plug. It still looks new. Checked all fuses....good. Put it all back together, hit the starter again and still no luck. Gave it some throttle and hit the starter and it tried to fire. Did it again and it finally started. Rode it around the parking lot a few minutes...it seemed to run fine. so we geared up and hit the trail. 10 minuted in, we stop and both comment that our bikes are not at full power. Mine still has difficulty starting, but stays running after started and idles fine. Sounds like a fuel pump right. Well, about an hour later, his bike seizes up. we were able to roll it to move the piston but he has zero compression. So, I ride out alone, get the truck and go get him.

He and I are thinking bad gas. I have spent all night reading about bad fuel pumps. Anyway to tell from looking at the pump if dealer was correct and mine had been replaced? Would rather drain bad gas than deal with fuel pump expense and bad gas would explain the coincidence of our mutual poor engine performance today.

your thoughts are appreciated.

Did you hear your fuel pump spin up when you turned the key?

Sarah

yes. fuel pump activates on key as usual. I did start it up before loading onto the trailer at the house. It fired right away, but I did not let it run for more than 30 seconds or so. And never revved it. So I cannot know for sure if the problem was there prior to the gas fill up.

There can be several things causing engine not starting.

clutch switch.
kill switch.
kickstand switch.

Some of these can be intermittent, too.. bad connections, dirt or corrosion in the switch.

I also had a similar thing happen when dumping my bike in some ruts. My handlebars twisted a bit, which cause the plug that goes to the starter switch to pull out. It is under the tank. I had to pull the tank & loosen the radiator to get at it, then plug it back together. It actually was intermittent at first.. the connector was sometimes allowing current to flow, then stopped completely.

The lean angle sensor can also cause a problem. If you drop the bike while running, it will kill the engine. when you stand the bike back up, you have to turn the key all the way off, wait a few seconds, then turn back on to 'reset' the lean angle sensor.

It does not sound like a fuel pump.. probably one of these other things.. & since both of you had problems at the same time, your fuel source is definitely suspect.

good luck on troubleshooting.

thank you sir. I thought about those darned safety switches, and fiddled with the connections as part of my trailhead troubleshoot. But it seems fuel / spark related instead of electrical / switch related because it will fire up when I give it some throttle with the start button....like you would a carbureted motor. Combine my buddy's trouble, and our focus is on the fuel....maybe just unfortunate coincidence, but thats where we are.

Does anyone know if you can visually verify if the fuel pump has been replaced.....serial number, different color parts, etc. ???

I've not read of a visual difference in the pumps. Let us know how this turns out. Like you've said, suspect the gas.

Sarah

My new pump looked exactly the same

thanks. Will post follow up when its fixed.

Removed, drained & dried out the tank yesterday. Put in 1/2 gallon new gas with some ethanol treatment and SeaFoam. Bike fired up, ran around the neighborhood ok. Got home and it still stalls when giving minimal throttle from idle rpm. I have the airbox flapper mod and AIS removed. Is there a chance those mods have me running so lean that there is just not enough fuel at low rpm's...or is that more related to fuel pump volume...or lack thereof? I have a FMF programmer and Q4 ordered, so maybe that will solve the lean problem if there is one.

When you checked the spark plug in the trail how did it look? Did it have a white coating or was it a nice brown color? that's a good indicator if your running lean. Air filter another possibility?

too bad you don't live around here, I would have taken my bike to your place to hook my tank so we can determine if the fuel pump is the issue.

thanks for the offer Bored. Plug looked good, but its real new....only a few 100 miles. I thought about the airfilter. It is due for a cleaning, but its not that bad.

Where in Florida?