St1300 intermittent loss of power help needed

Hi, I've just bought a 2006 st 1300, runs fine , but on an odd occasion loses power and runs rough, feels like it's running out of fuel, you have to slowly bring on the revs to get the bike to move, if you rev up to 4000 rpm too quickly the bike just dies as if fuel is not getting through quick enough.

if you turn the engine off and restart it will run fine again. It's as if something is re setting when you do this.

anyone had this problem ??

Sounds like you may have a failing fuel pump. Also make sure to pull the five way tee off under the throttle bodies and clean and make sure there is no gunk in them.

Just wondering why, after turning bike off and then on again , it would run okay for a while , and then reoccur .

Fuel pump. Runs better after you shut it off because the pump is probably cooling off.

Will look at changing this then, I believe you can use a car fuel pump instead of honda genuine, should I also clean the 5 way tee and change fuel filter

Or you could have goop in the vacuum lines and its getting sucked in and out of the TB's.
Pull and clean the 5 way tee and replace the lines with new 4mm tubing, and to a TB sync.

The problem only occurs when I try and open up the throttle quickly,

Fuel pump.

How many miles on the bike? Does it happen when its hot outside (> 27deg C) or doesn't it matter what the temp is? Does it do it right after starting up or do you have to run the bike for awhile first?

I'm leaning toward a bad fuel pump but another thing you could check is to make sure that the electrical connections to both coils are secure...

Doe sit matter how much gas you have in the tank...like running it after hitting the reserve too long will expose the fuel pump (lack of gas covering it), causing the pump to get hotter.

Its happened with low fuel and full fuel. But thinking about it probably worse when low. Rode all day sunday without a problem. But rode today through slow moving traffic and thats when it started again

It could be bad gas in your system, this happened to me about 2 weeks ago. After adding Seafoam and riding 150 miles through the balance of the tank with intermittent problems, and the bike would not idle. At highway speeds, it would suddenly loose about 60% power, just enough to maintain 60 mph, but I could not accelerate. After a full tank of fresh gas and more Seafoam, the bike ran fine. Your problem could be bad gas, but if you are into multiple tanks with the same problem, maybe not. Try some Seafoam and see if it helps. Remember, you have a smaller lower tank that is isolated and may take some time to clear the problem, if it is bad fuel.

Update on this problem, I have checked the 5 way tee , and is totally clean, like brand new, so are the five pipes , no kinks in any pipes under tank, checked all connections, bike has done 32,000 kms, will take it out at weekend for a good run and report back, thanks for the replies.

Ok. Took the bike out today. Full tank of gas. Riding for over an hour or so. Fuel got to half way and then it started . First a little cough then loss of power. Would run but felt like fuel starve or some electrics breaking down. Stopped the bike and turned it on again right away. Set off again no problem. Its weird

I'd suggest making sure the tank vent tube is unobstructed. Open your tank when it happens next and see if it sucks air in. This is known as POOGS (phantom out of gas syndrome) in other makes and forums, only happens when tank gets below half due to vacuum forming in tank.

When ithappened I opened tank, no vacuum whoosh, Where is the tank vent tube ??

There is a vent tube near the back of the tank on the bottom that sometimes can get pinched if not properly installed in the clamp at the bottom of the tank.

You might pull off the coils and check for rust/corrosion on the underside of the metal tabs and mounts that the mounting bolts pass through. I had a similar problem last March. I believe the suspect coil got just hot enough to drive up resistance just enough to create a bad connection and take two cylinders intermittently out of play. Since cleaning up found corrosion and swapping coils I've put 16,000 miles on the bike including crossing the desert Southwest in 102F - 105F temps in July with no sign of ignition breakdown. Several threads have addressed coil connections or coil wiring causing loss of power.

https://www.st-owners.com/forums/showthread.php?136449-Loss-of-power-unusual-coloring-of-catalytic-converter

My two cents- FWIW:

Sure sounds like the fuel pump isn't keeping up. When you shut down the bike you normally run the engine in a condition (idle normally) that has a low demand on the pump. When you restart the pump has a chance to pressurize everything before you start the engine. Seems like low mileage for such a problem though.

I doubt it's a venting problem. It would seem to me that a venting problem would be more pronounced when the tank was nearly full. This is because the liquid fuel is non-compressible while the air at the top of a tank can expand a great deal before causing what we would term "a vacuum."

On the other hand, you loose (roughly) a foot of liquid head pressure (call it 1/2 PSI or so) when you go into the lower tank. If the pump system is having trouble keeping up with high demands, the pressure could be giving the pump a little "help."

Sounds silly, but I would definitely run some Sea Foam through it before I took it down to the pump.

When you are taking the plastic off, it would be easy to check the connections on the coil packs. These are simple spades and there has been some history of these being disturbed when the bike is being serviced. (Jack's simple rule: If its a Honda and quits working- check to see if I broke something before doing to much work.)

Ok , I'm really getting annoyed with this problem now, have replaced the fuel filter, fuel pump, and spark plugs,

when I did this the bike was wonderful , for one day, thought my problem was solved.
then next weekend I went out and after an hour of riding, it started to play up again,
I'm losing all confidence in this bike now, I'm scared to go on any long rides in case it breaks down,
had a quick look at the coils, and they looked good, not rusty or anything, no loose wires,
what can I look at now.