Stalling at Speed

So, I'm a relatively new ST 1300 owner. It's a 2003 non-ABS model, which was what my budget would allow. Would love to trade up to an ABS model someday...

I've had it six months, bought it with 45k miles, and it's been running flawlessly. I haven't had a chance to take it in for a dealer service yet (just a diagnostics check?), but I've done some basic maintenance, like changing/topping up fluids, new tires, checking brakes, etc. However, just in the last couple of weeks, it's had trouble holding an idle. It will just stall out. It was only happening occasionally on some starts and my temporary solution was to hold the throttle open for a bit until she warmed up. Then it happened a couple of times as I pulled up to a light. As I decelerated to a stop, the engine would die, but always started up no problem. Today, though, it happened twice while moving. Once, while on the freeway as I coasted to an off ramp, the engine died, but I hit the starter button and it started right back up. It happened again a few hours later on a surface street as I rounded a corner. The engine died on my down shift and this time it wouldn't restart at all. I stopped by the side of the road and tried to restart it unsuccessfully a couple of times. I waited just two minutes, tried again, and it started right back up. Didn't happen again on the rest of my ride home, although I was paranoid every time I decelerated.

A couple of months prior to this, when I had the lower fairings off, I found this little rubber thingy in my driveway. It's only about an inch long. It looks like it belongs to the ST, but I'm not sure. Does anyone know if it does and if it may be related to my little stalling problem?



Thanks for any advice or suggestions!

BTW, this is my first post here and I'm pretty sure I haven't posted this in the correct place. Please let me know if this topic is more appropriate in a different forum. Thanks!

The object is not related. It's a vent tube off of the back of the headlight assembly.

I might first try cleaning or replacing the 4 rubber hoses that connect the throttle bodies to a 5 way tee fitting. There are lots of threads on this. Clogged vacuum lines can cause low rpm stumbles and engines that stall at idle.

Thanks for that direction, Dave. I've got a service manual and it looks like I only have to remove the upper tank and air cleaner housing to get a look at those vacuum lines. Just take 'em off and check they're not clogged?

I'm finding quite a few similar posts to my problem and lots of advice to clean out the five-way tee. If anyone can take the time to just explain how to actually do that I would be very appreciative. Also, when removing that upper tank, it says to replace the joint hose and clip with new parts. Is that absolutely recommended?

ON, yes, strongly recommended as they are known to crack--but some of us have not replaced it every time when we've known the age of it. If replacing or if pulling the fuel tank without replacing, You'll want to run down the fuel to one blinky bar... then that joint hose doesn't have fuel inside it.

Is replacing the upper to lower fuel line necessary EVERY time you lift the tank? I replaced mine at 100,000 miles/10 years old. I had lifted the tank several times and had no failures. Others have had this hose fail. Have one on hand, GREAT idea, just in case. Scooter gave me a Honda kit number that not only contained the hose but some other items at a considerable cost savings over just the hose. I will try to get that part number. Hope cleaning those hoses help your problem.

You can blow out the goo in the tee with a can of brake cleaner or a pipe cleaner wet with brake cleaner or other solvent. I'm sure you will be careful with spraying brake cleaner - it doesn't need to go anywhere but through the hoses and the tee fitting.

Be careful removing the screws in the airbox base. They will be tight and are known to strip the heads out when removal is attempted. A properly fitting JIS screwdriver with a small set of vise grips clamped on the handle works for me but many others use an impact driver to loosen them.

Kevin_56 said:

Is replacing the upper to lower fuel line necessary EVERY time you lift the tank? I replaced mine at 100,000 miles/10 years old. I had lifted the tank several times and had no failures. Others have had this hose fail. Have one on hand, GREAT idea, just in case. Scooter gave me a Honda kit number that not only contained the hose but some other items at a considerable cost savings over just the hose. I will try to get that part number. Hope cleaning those hoses help your problem.

Click to expand...

+1. Like you I lifted the tank as needed for years with no problem and did not replace the hose until close to 120,000 miles - "just because". Even then the old one seemed just like the new one in regards to softness and pliability. The tank is supposed to be slid back to the maintenance position before lifting the tank. I think if this is not done it stresses the hose as the tank tilts up.

Here is an EBay link to the kit. It has the part number if you want to try to get it else where. The clamps are a major pain to remove. I would suspect really hard to replace. The new ones come with a nifty clip that holds them open to get positioned correctly. Once that is done you can pry that clip off and the hose is clamped.

Hey everyone, thanks for the help so far. All good advice and gets me going in the right direction with god tips as I get started. I'm actually going to start this process with half a can of Sea Foam, just to see if that won't help. Can't hurt, right? I know that won't have any effect on any gunk in the 5-way tee...

Thanks all!

Out of curiosity, does the bike have a K&N filter?


The reason I ask........

https://www.st-owners.com/forums/showthread.php?125016-K-amp-N-filters-causing-junk-in-lines

JoeP said:

Out of curiosity, does the bike have a K&N filter?

Click to expand...

No, it doesn't, but it was one of my planned upgrades. Thanks for the heads up!

Well, the SeaFoam easy fix was spectacularly unsuccessful. Dumped a little in at home, went to fill up at the gas station, and thought I'd go for a test ride. Got to the gas station okay, but the engine died on me while pulling out of the station (I put the SeaFoam in at home in a 3/4 full tank). It started up again, but now the gas level gauge is flashing at me. Got down the street half a block and it died shifting into second, but this time ALL the dash gauges have gone dim and everything is flashing at me and it won't restart. Waited a couple of minutes, it started after a few tries (all the gauges came on normal) and limped home carefully so that i wouldn't have to push it. It happened a couple of more times on the way back; dies, dash flashes, wait a bit, restart to try and get home. Now to look up what all the flashing means...

Now it sounds more like an electrical problem. I'd start checking the ground connections, kill switch, side stand switch, and the large connector on the left side under the Tupperware. The large connector has a green ground wire that is known to cause problems.

Kevin_56 said:

Is replacing the upper to lower fuel line necessary EVERY time you lift the tank?

Click to expand...

The hose and clamps get replaced when you remove the tank. Raising it without replacement is fine as long as you don't exceed what the limit strap allows.

--Mark

Rick77 said:

Now it sounds more like an electrical problem. I'd start checking the ground connections, kill switch, side stand switch, and the large connector on the left side under the Tupperware. The large connector has a green ground wire that is known to cause problems.

Click to expand...

would start checking the grounds and the battery terminal connections for cleanliness and tightness.

Check for the ground cap recall. 03 bet it was not done. SEARCH this site.

Check battery= YOU must have 12.6 volts at the terminals for the ECM to be happy. Yes 12.6 volts.
check battery in morning after the bike has set for/or overnight.

Here are the ST1300 recalls:
https://www.st-owners.com/forums/forumdisplay.php?419

This may also help even though you're not blowing fuses:
https://www.st-owners.com/forums/showthread.php?77922-ST1300-Intermittent-blown-fuses-caused-by-wire-rub&highlight=left+wire+harness

Blrfl said:

The hose and clamps get replaced when you remove the tank

Click to expand...

Do you replace your rear caliper stopper bolt every time? The fuel hose is different. Should it fail, things could get real interesting.

If I were to have to remove my upper tank, knowing my hose is only 1 year old, I would inspect it and if not damaged from removal, I would reuse it. Now getting those strong clamps back on might cause me to get the kit to take the frustration level down to a 1.

I am going to get one of the kits to have on hand. One never knows when you just may need to do service requiring upper tank removal. Especially with an 11 year old bike.