Suggestions please: Surging in traffic, cuts off -wont idle very HOT

2009 ST1300 88k under warrenty

Would like sum advise please...

in March during bike week was the first sign of any problems, sitting in heavy traffic trying to get to main st
the idle started coming down from 1100 to 500. I rev'd it, it cut off. Restart but not easy, rev'd, cut off.. did
this about 5 times and cut down a side street and found a parking lot to cool in shade. only 75 degrees or so outside.
bike i could tell was very hot, but still only 3 bars on temp. walked to find some food, came back an hour or so, and hauled tail
to the motel with no problems. Next day, rode 6 hours home, no problems.

a month went by and i was low on fuel and it started surging while at speed, i was low on fuel but had been lower many many times, i
coasted into a fuel station and went on about my business.

another month has passed, no problems, but also not stuck in traffic until i was headed to bike night during rush hour, wouldn't idle, started
surging when i got out of traffic by taking a side street. Let it cool in a parking lot for 45 min... and rode home, bike being very hot but
still only 3 bars on temp. 90 outside temp

pulled right side plastic to check coolant level. i was surprised to find it was full, and the fans do kick on

the bike is under extended warranty till may 2018
my concern taking it to the stealership is they will hand it back to me saying it didn't happen to them. I will go this route tho

any ideas what the problem is? fuel pump?

i dont wanna get stuck with a high labor fee if they say its not a warranty issue

i have the plastic off, should i leave it off if i take it in? farkles are never put back on right anyway

thanks for reading

That has the signs of a failing fuel pump. If that were mine, I'd run the tank down to 1 bar and put in a replacement fuel pump. There are a number of threads about part numbers of a common fuel pump (available at your local auto parts store) that is a direct replacement. See the last couple dozen or so posts in this thread for fuel pumps others have used: https://www.st-owners.com/forums/showthread.php?118684-ST1300-Fuel-Pump-Replacement

Per the Factory Service Manual, you're supposed to replace the gasket when the fuel pump assembly is removed from the lower tank... some do, some don't. It is part number 17574-MN5-000.

ok, thanks for the confirmation...... i have ordered parts and worth not having to take to dealer

ScooterGdawg said:

.... and worth not having to take to dealer

Click to expand...

My thoughts too. The dealer is unlikely to take the time to repeat the issue, or worse you hand over the bike to them and thy call back 2 weeks later with "we tried but couldn't duplicate". It doesn't hurt to describe the problem and ask the service mgr if they'll replace it under warranty. If they do, great!

You may want to also check a couple other things such as what the plugs look like? Are they Tan, white, or wet? What condition is the air cleaner in, is it dirty?
Even though you have not gotten any codes thrown, I would check the 5 way tee to see if its clogged up, and maybe to a TB sync while I was under the tank.

I think it sounds like a bad fuel pump there have been quite a few cases and all acted the same way.

Igofar said:

You may want to also check a couple other things such as what the plugs look like? Are they Tan, white, or wet? What condition is the air cleaner in, is it dirty?
Even though you have not gotten any codes thrown, I would check the 5 way tee to see if its clogged up, and maybe to a TB sync while I was under the tank.

Click to expand...

Plus 2

Igofar said:

You may want to also check a couple other things such as what the plugs look like? Are they Tan, white, or wet? What condition is the air cleaner in, is it dirty?
Even though you have not gotten any codes thrown, I would check the 5 way tee to see if its clogged up, and maybe to a TB sync while I was under the tank.

Click to expand...

Sent from my SAMSUNG-SM-G935A using Tapatalk

That does sound like classic fuel pump on the way out disease.
I'd check igofars list simple enough and you're gonna be in there.

If you get to the fuel pump checking stage, check both the pressure test and the flow test. You can pass the pressure test and still fail the flow test. If the dealer's random assembly department is a concern, the pump if not too bad a DIY job. If you don't have a way to check pressure I'd probably just put the new pump in assuming the plugs vacuum line air filter etc. look ok.

Just thinking outside the box for a minute...was anyone under the tank recently? Maybe replacing an air filter or inspection? Wondering if maybe a pinched off hose (smog or vent) could be pinched under the tank?
Just thinking out loud.

I agree it is probably a fuel pump issue, but when were the valve clearances last checked? I am referring to the rough idle.

ScooterGdawg said:

ok, thanks for the confirmation...... i have ordered parts and worth not having to take to dealer

Click to expand...

Truth be told, I don't trust PowerHouse Honda to change their minds correctly much less change a fuel pump.