Poor running 2003 ST 1300, can’t resolve need help

[TerryS]

I had good idle but rough running and reluctance to rev when I got my old ST1100 roadworthy. Finally found low voltage reaching the coils, which turned out to be due to a dirty connector feeding power to the right bar pod where the kill switch lives.

 

[Dusty Roads]

Check the sparking system. I had an article on this which seems to have been lost. I’ll see if I can locate it on my computer and add it back.

The ignition coils rely on a good frame ground. There is an earth strip that can corrode that makes contact with the frame round the back. Take the coil off, clean it up.

The HT leads are a push fit onto a deep seated spike one you have undone the thumb screw nut. Make sure that the copper leads have not turned to green verdigris.

The resistance of the spark plug cap should be 5k ohms. You can measure it with the HT cable attached.

The plug cap is a screw fit onto the HT cable that connection could be corroded inside. Put a mark on the HT leads where the cap and cable meet. Check the core for verdigris. Check the cap resistance again without cable attached. Screw the cap back on.

You can use ordinary copper cored Ht leads, but if you do, you have to find a way to put a gland on the at the coil end so that the thumb screw can push the gland and cable onto the spike and hold it there firmly. I have not found a suitable non-Honda replacement for the Honda plug cap.

If this is the issue - in my experience it results in unreliable power, almost stalling when setting off, Rough running and requires high revs to keep the engine pulling.

Had the coils off and made sure all is clean and have good contacts. Everything was pretty much spotless but cleaned, sprayed cleaner. The left side coils have aluminum spacers which mount directly to frame. This I found a bit strange but the steel mounting bolt must be the contact to ground. Copper is nice and shiny and the caps as well. Tested coils, cables, caps again and all show a good ohm reading. At idle there is still a very slight what seems like a miss.

 

[Dusty Roads]

I had good idle but rough running and reluctance to rev when I got my old ST1100 roadworthy. Finally found low voltage reaching the coils, which turned out to be due to a dirty connector feeding power to the right bar pod where the kill switch lives.

Going out to garage again to start testing wiring. Hope to find something that I have not thought of as you suggested.

 

[eyrepb]

Back to my throttle body sync recommendation. I for one, was surprised at the smooth idle and pull when I dialed mine in proper.

 

[SammyG]

I seem to remember the 2003 ST had a recall for a grounding issue. I can't recall the exact location of the grounding problem but have heard of an issue somewhere behind or near the back of the headlight area.

Maybe you can research further the 2003 recall and check all the grounds you can find.

 

[Dusty Roads]

Gentlemen, think I might of found the problem yesterday. Removed the mufflers and took it for a high speed test run. Vent very very fast, it revved up no problem and pulled like a locomotive.
It seems the problem is back pressure from the mufflers. Have never heard of this and the only thing I can think of is that the bike spent a lot of time just sitting with the mufflers degrading and clogging up.

Back home when my heart beat slowed down I put the mufflers back on and remembered all I heard about the high speed wobble, which thankfully I did not experience. Temp gage read 1 bar and when I started the bike it idled at 600rpm. It always idled at 950-1000rpm. Just wondering if the ECU can and is compensating for the lack of restriction. Will take the bike out in a few days after I put it back together and see if it runs the same as before.

If anyone has had this experience with mufflers let me know. Sure would like to know of a remedy.

 

[Andrew Shadow]

If anyone has had this experience with mufflers let me know. Sure would like to know of a remedy.

Are they the Honda OEM mufflers? If so they do not have any type of insulation in them like many aftermarket mufflers with "glass packs" do. They are just a series of tubes that force the exhaust gas to circulate in a certain way before being able to escape. They would have had to have sat with considerable moisture in them for a long time before that material would have deteriorated a significant amount. Have a look inside of them with a good flashlight to see if there are any signs of rusted flaking metal.

If they are Honda mufflers and there is excessive exhaust restriction, and assuming that there is no added restriction due to something like a dead mouse in there, the more likely cause of increased exhaust restriction is a defective catalytic converter. The catalytic converter is the smaller cylindrical piece immediately in front of the muffler. As a quick test just for kicks, if you have one of those non-contact temperature readers, check to see if there is a significant difference in temperature between the two catalytic converters. The hotter one will be the one that is more restricted.

I can't tell you what a normal temperature would be as I have never checked this on my ST1300. I also can't tell you how much of temperature difference between the two sides is still considered normal. Dave (@dduelin) had a defective catalytic converter if I remember correctly. Maybe he can advise what the symptoms were and how he troubleshooted it to give you an idea.

 

[drrod]

Sounds (pun intended) like it is time for

https://delkevic.com/product-catego...-models/motorcycles_honda_2003-models_st1300/

 

[Al st1100]

Gentlemen, think I might of found the problem yesterday. Removed the mufflers and took it for a high speed test run. Vent very very fast, it revved up no problem and pulled like a locomotive.
It seems the problem is back pressure from the mufflers. Have never heard of this and the only thing I can think of is that the bike spent a lot of time just sitting with the mufflers degrading and clogging up.

Back home when my heart beat slowed down I put the mufflers back on and remembered all I heard about the high speed wobble, which thankfully I did not experience. Temp gage read 1 bar and when I started the bike it idled at 600rpm. It always idled at 950-1000rpm. Just wondering if the ECU can and is compensating for the lack of restriction. Will take the bike out in a few days after I put it back together and see if it runs the same as before.

If anyone has had this experience with mufflers let me know. Sure would like to know of a remedy.

I believe there is a converter at the front of the muffler.

 

[SammyG]

Yep, if t was run for a long period of time with a misfire it likely burnt up one or both of the cats, slowing down the exhaust gasses exiting.

 

[Dusty Roads]

Are they the Honda OEM mufflers? If so they do not have any type of insulation in them like many aftermarket mufflers with "glass packs" do. They are just a series of tubes that force the exhaust gas to circulate in a certain way before being able to escape. They would have had to have sat with considerable moisture in them for a long time before that material would have deteriorated a significant amount. Have a look inside of them with a good flashlight to see if there are any signs of rusted flaking metal.

If they are Honda mufflers and there is excessive exhaust restriction, and assuming that there is no added restriction due to something like a dead mouse in there, the more likely cause of increased exhaust restriction is a defective catalytic converter. The catalytic converter is the smaller cylindrical piece immediately in front of the muffler. As a quick test just for kicks, if you have one of those non-contact temperature readers, check to see if there is a significant difference in temperature between the two catalytic converters. The hotter one will be the one that is more restricted.

I can't tell you what a normal temperature would be as I have never checked this on my ST1300. I also can't tell you how much of temperature difference between the two sides is still considered normal. Dave (@dduelin) had a defective catalytic converter if I remember correctly. Maybe he can advise what the symptoms were and how he troubleshooted it to give you an idea.

Everything on bike OEM and low Km. Tried to have a look inside of muffler and from what I could see they look normal. Not able to see that much inside.
The bike did sit in a damp shed “unused” on its sidestand for a long time. Over the years anything could of happened with moisture and rodents. Found the air filter full of pink insulation.
Have a temperature tester and will measure the catalytic converters for variation.

 

[Dusty Roads]

Yep, if t was run for a long period of time with a misfire it likely burnt up one or both of the cats, slowing down the exhaust gasses exiting.

The misfire was noticed within the the last couple of weeks. Usually go out Sunday mornings for a few hours. One morning it was noticeable on the bar end after starting it up again following a hour or so ride.
Bike got hot in city traffic but never heard the fans come on. Had them running before.
After that one occurrence I started troubleshooting the bike and have not really noticed it again.

 

[ST Gui]

Temp gage read 1 bar and when I started the bike it idled at 600rpm.

Did you keep the bike running long enough for the gauge to show 3 bars?

 

[Dusty Roads]

Did you keep the bike running long enough for the gauge to show 3 bars?

Only ran for about 2 minutes or so after I put mufflers back on. Have not been able to go out on it and test it hot. House repair work being done for a few days.

 

[Dusty Roads]

Might of found problem,
I removed the mufflers and had then soaking in a lot of dish soap just above the cats. Saw on you tube someone suggested this will clean the cats. Had them soaking for two days, rinsed them out by dipping up and down and not letting water above the cats. Dried in the sun for hours.
Did not notice any great improvement if any.
Was able to locate and buy a pair of mint mufflers off a 2013 with same mileage as mine. They were sitting in garage for about two years. Installed last weekend and tested them out on Wednesday.
Noticeable improvement. Bike revs a lot easier and smoother under load. Pulls much better 4-5 gear and is smooth under acceleration.
When time permits will sync the throttle bodies and see if I can get it to run even smoother. Unfortunately there is still a lot of heat and the only cure it seems is to cut the mufflers open and remove the cats. Something to think about over the winter though not a easy job with having to tig weld back together. All of the guys I knew that were great welders are gone or retired. If I cut them open will post images of cats.
Original mufflers image

 

[ST Gui]

Saw on you tube

This gives me pause. There are some knowledgeable people on YT but also a lot of chaff to wade through to get to the wheat. Maybe a soak in Palmolive might have helped or may not have hurt if there were already internal damage.

Nice score on the new kit. And congratulations on getting your ride's performance improved.

When time permits will sync the throttle bodies and see if I can get it to run even smoother.

Putting out big fires to find the smaller ones.

I'm one of the possible "lucky few" whom isn't bother by the heat. And I don't think I'd be pleased with the exhaust note with the cats removed. But if that is something you do I'd like to hear about it. Not a fan of what I've heard of the Staintunes/Delkevic/Two Brothers kit but they are popular.

The factory exhaust on my 750–K4 had a great note at idle and speed. But I swapped them for some Paul Dunstall mufflers that sounded amazing but not loud if I wasn't WOT. The build quality wasn't good so I went back to the pocketa–pocketa pipes.