I've had the bike for about 5 months and never had this problem until 8 days ago. Was riding on the highway and the engine started cutting out a couple times then was fine for a minute then did it again. I got off the highway and rode into a parking lot and had to pop the clutch to get it to run twice until I got to a parking spot. As soon as I pulled in the clutch lever to stop it died. I've read on quite a few posts that same basic scenario but the symptoms don't seem to match exactly. I don't lose any dash lights and if I turn the key off and back on the fuel pump will prime and then hit the start button the engine will turn over but the bike won't start. If I let it sit for about 10 minutes it'll start again and will last another 10 minutes or so. I've checked stator, r/r, engine stop relay, fuel cut relay, kill switch, fuses, ground block in the wiring harness, ground terminals on the back of the engine, bank angle sensor, kick stand switch, checked power and grounds in ecm per service manual. I pulled the plugs as a mechanic I know suggested the pressure regulator and 1, 3 and 4 look like they should, little bit of tan, 2 is considerably darker. Presently the only parts out of stock on the bike are Jardine slip on and k&n filter, no power commander or (to my knowledge) any change to the stock mapping in the ecm. At this point I'm just chasing my tail so I'm looking for some fresh insight. Any help would be greatly appreciated, I realize it's winter but living in Florida there is no off season so I'm looking forward to getting back on the road but can't afford to just replace stuff for no reason. Thanks in advance.

 

checked the fuel and air filter to make sure they are clean??

The coils (or something else) could be loosen ground or power too, but it would seem it would be more random if they were.

 

I checked the fuel filter last night, clean. The air filter was cleaned about two months ago but I reinspected it last night and it still looks clean. Other than looking at the wiring harness and checking for nicked wires I can't find anything obvious so naturally I'm pulling my hair out now. Thanks for the reply. I'm just trying to narrow it down to at least one system. Either it's fuel, electrical, mechanical. Like I said I don't SEE anything wrong and that's what's driving me nuts.

 

only advice I have is next time you are messing with it, let it run n act up, then check the vital electrics n see if they have power, if so then move on to the next. try to eliminate it down if possible.

I feel ya, those weird lil problems drive me batty lol

 

Try the idle adjuster. mine came loose the other day for whatever reason but the bike wouldnt idle after initial start up, i had to keep the throttle revved at 1800 which is not easy to do in traffic but the bike ran really rich and as soon as you let off the throttle the bike would die.

 

Regarding the fuel pressure regulator, did you replace it or inspect it? or only look at the plugs? The FPR can act in wierd ways when they begin to fail. If you haven't already, I'd pull the vaccum line from the FPR and see if there is gas inside the tube. If there is, the FPR is bad. There is also a flow rate test that be done, but I'm not sure what it is for your specific bike.

The odd part is the 10 minute thing. Is there anyway the gas tank vent tube is plugged? If its plugged, gas can only flow until the air in the tank is used up. let the bike sit for 10 minutes, and most of the air is leaked back into the tank. When it dies next time, pop open the tank and see if you hear a vaccum sound of air whooshing in. If you do, the vent tube is plugged somehow.

Also, think very hard if there was anything you did to the bike recently.

Other than that, your going to have to do what PG suggested and look really hard next time it happens to see if anything is out of spec. Relays can heat up and fail hot, but be ok cold. So I would probably start looking at those first.

Oh yeah, when the fuel pump primes after it dies, does it sound normal? There is a difference in sound between a fuel pump that has fuel in it, and one that is dry. if you can listen closey, you may be able to hear a difference.

 

I had first checked the vacuum line from the fpr and it was dry then I noticed there was a small crack in the vacuum line from the fpr to the t where it splits to the 1 and 4 cylinders so I replaced that piece of tube and inspected the rest of it. Then I took the fpr off and looked in there, I was looking for gunk in the fuel rail etc. everything looked fine so I put it back together. I heard the difference between a dry pump and a wet one last night when I put gas back in the tank and let it prime and it never sounded like the pump was dry before. I'll check the vent though. I did replace the fuel cap a couple months ago because the vent was blocked in it and it was causing my tank to expand or contract until I opened the cap. the new one only has a screw on cap with a check ball system built into the base so I'll check and see if that's got crud in it causing one of the check ***** to stay shut. Thanks for the info, I'll keep digging and posting my findings until I get this sorted out.

 

Now just to see if anything had changed after all my poking and prodding I put it all back together and put new gas in it as the fuel I got previous may have not been good. (I've run 5 year old gas out of an old cb 750 in my lawnmower for 4 months with no problem) So far it will idle in the drive way for 20 minutes with no problems. Did notice the sucking sound when I took the cap off after I shut it down, looked further and apparently the po had bocked the vent tube with a rubber vacuum plug so I'll take that off and see if anything changes. I took it for a ride a few nights ago and it ran in the drive way for 15 minutes then after it cooled off I rode it for 15 minutes and it died. So I'm figuring it's either fuel pressure or the vacuum thing as described earlier or it's something electrical that fails under load, extra power through the system from running off idle (r/r, stator), extra heat from running off idle. But as it sat for 20 minutes the fan kicked on at least twice so I don't think it's something caused by ambient heat but more electrical resistance heat. I don't know, still stabbing in the dark. If anyone else can make sense of my latest findings I would greatly appreciate it. So far I've gotten some good ideas from you guys so I'm hoping we can get her back on the road soon.

 

If your hearing the suction noise, I would lean toward that being the issue. the tank is not properly vented and it will stop the flow of gas if can't get air to replace the gas that being pulled out by the pump.

Also, just an FYI, most tanks are not vented through the gas cap, but a hose. The vent line will usually be exposed at the lower fairing. its also usually grouped with other hoses as well. They vent them this way so any gas that may make it out of the vent, will not spill onto the rider, but out the bottom of the bike.

 

Ok, I'll unblock the vent tube nipple and run a hose down for it and see if that solves it. Thank you very much, I really appreciate all the help I've been getting from the people on this forum.