Cutting out again

[Tdinova]

This is the 3rd time this summer that my ST1300 acted really bad. It was like cutting out when 1 accelerated. Idling along was not that bad but when I opened the throttle the engine acted like it lost all fuel or electricity. The gauges kept lit but the engine stumbled then picked up then stumbled again. It happened when the fuel gage was at the half way mark. I was 100km from home but i stopped 2km before home and refueled 16.71L. Now it works great again..

I should also add. In neutral I could Rev the engine with no cutting out, it's happens while under load.

Does this sound like fuel pump failing?

Any thoughts

 

[Tdinova]

I should have mentioned that I changes the spark plugs, syn the throttle body, cleaned the 5 way T and remived and cleaned the 5 lines heading to the T after the 1st time.
added 1/4 can of seafoam

No FI light flashing

Rolled 134000km today

 

[Willsmotorcycle]

Fuel filter, dirty gas? Smarter riders will be along shortly.

 

[diferg]

I had a similar problem about 2 years ago. bike would surge and almost die was only smooth after reaching about 4000 rpm. my problem was a vacuum leak in the cruise control unit that I had installed years before. I disconnected the cruise control at its vacuum source and the engine returned to normal immediately! I hope your problem is this easy to solve. The hard part is finding the problem!

 

[Tdinova]

I had a similar problem about 2 years ago. bike would surge and almost die was only smooth after reaching about 4000 rpm. my problem was a vacuum leak in the cruise control unit that I had installed years before. I disconnected the cruise control at its vacuum source and the engine returned to normal immediately! I hope your problem is this easy to solve. The hard part is finding the problem!

No cruise control on mine. Thanks for the reply

 

[oude geit]

Fuel pump and filter. Test pump pressure.....

 

[Nexus]

I've had a similar problem. After around 150-200 miles or so, the bike starts to act like it's running out of fuel (hesitation, lack of power, etc). Turning the ignition off the on again temporarily fixes the problem. It might be a similar problem to yours but I don't know what the fix is.

 

[Igofar]

This is the 3rd time this summer that my ST1300 acted really bad. It was like cutting out when 1 accelerated. Idling along was not that bad but when I opened the throttle the engine acted like it lost all fuel or electricity. The gauges kept lit but the engine stumbled then picked up then stumbled again. It happened when the fuel gage was at the half way mark. I was 100km from home but i stopped 2km before home and refueled 16.71L. Now it works great again..

I should also add. In neutral I could Rev the engine with no cutting out, it's happens while under load.

Does this sound like fuel pump failing?

Any thoughts

Yes

 

[Igofar]

Sounds like your fuel pump, and/or filter are suspect.
I see a lot of folks missing this because they just listen for the pump to wind up, then because they heard it pressurize, write that off as a possible cause etc.
I have found damaged hoses, in the tank that folks don’t see, bleeding off pressure and stumbling under load etc.
I have also found fuel filters so gummed you that you couldn’t force fuel through them.
However, with that said, the first thing I would check would be the lines out of the smog canister to make sure they are not clogged up creating a vacuum lock.
I would also check the return hoses under the tank if you have been under there, to see if you pinched a line etc.

 

[Rob20111]

How many km's on the bike?

 

[Al Gully]

How many km's on the bike?

See his 2nd post on here.

 

[Al Gully]

Mine was stumbling too when my fuel tank was at 2 bars or less, so I bought all the bits and pieces to change out the fuel pump, fuel filter, gaskets and banjo washers, then said the heck with it and went and bought another 2005 ST ABS instead in May.
If you buy an aftermaket fuel pump, don't use the hoses that come with it. Use the original hoses or new hoses from Honda.

 

[Tdinova]

How many km's on the bike?

134000 km

 

[Rob20111]

Mine stumbled too but only at 2-4000 rpm, and much worse in hot summer weather.
I replaced the pump, filter and strainer.
As the bike had sat a lot before I purchased it (10k km in 17 years) I wanted to rule out pump or filter damage from old fuel.
Later I also found small splits in two of the spark plug boots. Replaced all 4.

When purchased last year I immediately did the following.

Oil/filter
Air filter
Spark plugs
Starter valve sync
5 way T and new hoses
Thermostat and coolant (stuck open)
Brake and clutch fluid

Running good now.

Start by checking the simple easier things first before you buy a pump and filter.
Pay attention to ignition components, inspect visually and carefully for damage, test with an ohm meter, caps should be 5k ohms.
I also found corrosion on my right side coil where they mount to the frame, which I cleaned up.
If you need a pump I recommend the All Balls pump from FortNine.
Filter from Honda.

 

[Tdinova]

I have also found fuel filters so gummed you that you couldn’t force fuel through them.
However, with that said, the first thing I would check would be the lines out of the smog canister to make sure they are not clogged up creating a vacuum lock.
I would also check the return hoses under the tank if you have been under there, to see if you pinched a line etc.

This morning i siphoned the gas down to 2 bars, went for a 20 min ride with no issues...
Is the smog canister on the right near the back of the engine, I will attach a picture with an arrow on it. If so I removed each line and blew in them. None are cracked or blocked . I even disconnected the larger by the 5 T , blocked it with a finger and blew.. no leaks or restrictions. All the lines below the tank are not kinked or rotten. Monday is Thanksgiving in Canada so i call My Stealer for availability of parts. I may remove fuel pump and check that today
See attached

 

[Tdinova]

Looks tempting.. 100 compaired to 1000

 

[Igofar]

Looks tempting.. 100 compaired to 1000

I would strongly urge you NOT to use the piece of fuel line that comes in that kit!
The Honda pieces are designed to be submerged in fuel, and have writing stating so on the line itself. Many, if not all of the cheaper aftermarket ones only provide you with a generic piece of fuel line that will swell up and fail after a couple thousand miles, or 4-5 months.
The pumps are ok, but use the Honda fuel lines, filter, and packing (gasket)
Be aware that there are two different torque sequences to tighten down the top of the lower tank.
Be VERY careful, as the opening is razor sharp, easily bent (think paper thin) and unless you trust your torque wrench (had it calibrated in the last couple months) don't torque them with it.
The studs will/can snap off requiring you to purchase a whole new lower tanks assembly.

 

[Igofar]

This morning i siphoned the gas down to 2 bars, went for a 20 min ride with no issues...
Is the smog canister on the right near the back of the engine, I will attach a picture with an arrow on it. If so I removed each line and blew in them. None are cracked or blocked . I even disconnected the larger by the 5 T , blocked it with a finger and blew.. no leaks or restrictions. All the lines below the tank are not kinked or rotten. Monday is Thanksgiving in Canada so i call My Stealer for availability of parts. I may remove fuel pump and check that today
See attached

Its not the top of the canister that will cause the issues, its the lines on the bottom of it.
See picture below.
You may also want to look down underneath your engine, at the rear, you'll see a single 10mm bolt that holds a metal retaining loop, that your 3 lines are routed through.
For some stupid reason, Honda chose to point them forward, which clog up with dirt and debris, and cause issues.
I cut the hoses short enough to be retained by the rear crank case cover band, and let them point straight down (like every other bike used to).

 

[Igofar]

I noticed a couple FLAGS from your pictures....
1st, the number #1 and #3 cylinders are running like crap as indicated by all the dirt on your throttle bodies etc.
And 2nd, I see you've replaced your 5 way tee hoses with much longer ones, extended out forward of the throttle linkage.
This was suggested a few years back, trying to fix an issue that didn't exist, and actually causes more issues than it fixes.
You've created a "kitchen sink trap" by dropping the tee down low in the valley, and extending the hoses. Crap can gather in these hoses, and cause issues such as you are having.
While you may open the tee up and not see anything in the tee, you've provided a long area for crap to build up in, and not be able to clear itself.
I find that making the stock length hoses about 1/4 inch longer, it stands the tee up a bit, and allows everything to exit back down into the TB nipples, rather than pool in the lines etc.
I've found several members with poor idling/running issues that tried that modification ask me to remove the extended lines and go back to the shorter style, which cured their issues etc.
Just something to think about.

 

[Tdinova]

Thanks for all the info Igofar I really appreciate it. I was going to remove and inspect the fuel pump, filter tomorrow but I'm going to change my attack. I'll check the bottom of the canister 1st. Then shorten my yellow hoses and put them back inside the throttle body as you suggested. Then check the bottom hose for blockage.

Once again I really appreciate your help.