St1100 shaking and stalling out

[Chrissn3]

I have an '02 st1100 that will shake and stall out at stops. I have taken it in for service for cooling issues and asked them about it, but they didn't experience the problem. They did fix the cooling problem. It doesn't always do the stalling out. It malfunctions mostly around the subdivision due to lots of stop signs. If I go many miles and then drive through subdivision it doesn't do it. I am clueless as to why it does this. I've tried different fuel grades, but it seems to not help. Most people say they use regular. Person I bought it from said mid grade.

 

[Gerhard]

If you increase idle by a 100 rpm would that keep the engine from stalling?

 

[Uncle Phil]

My hunch is either the fuel pump or the fuel cutoff if you have swapped the fuel filter. Regular grade is fine in all of my ST1100s.
RPMS should be set to 1,000 at idle. If it won't idle there, your low speed jets are probably clogged.
I presume you know about the 'choke' which is really not a choke but a fuel enricher for warm ups?

 

[Gerhard]

One other thought, in one of the last years I had 1100 it weird off idle response and it was recommended that I add a bottle of fuel injector cleaner with the next fill up and it seemed to resolve the issue. I was never sure if it was stale gas that was the issue or if the injector cleaner actually did something.

 

[Bikeric]

Welcome to the forum from Cornwall UK! You could try the fuel cut-off valve bypass to eliminate that - look at the ST1100 posts in the Articles section at the top of the page. Hope you get her sorted out.

 

[John OoSTerhuis]

Set idle to spec, run a bottle of Seafoam or Techron through a tank, and replace the spark plugs w/Iridiums. FWIW

John

 

[CYYJ]

Hi Chris:

As John Heath suggested in post #2, check the fuel filter first. That's the easiest fix and it is not an expensive part. The filter is located on the right side of the fuel tank, all you need to do to get access to it is remove the false fuel tank cover.

There is also a 'known issue' with the ST 1100 vacuum operated fuel cutoff valve failing. This valve cuts off fuel flow when the engine is not running. An easy way to test it is to bypass it temporarily and see if this solves your problem. This article explains how to do that: ST1100 - How to do an emergency bypass of the fuel valve. If that solves your problem, you will need to purchase a new bypass valve (after first inspecting the vacuum hose to make sure it has not cracked or come loose).

Michael

ST 1100 Fuel Filter

 

[Chrissn3]

Wow, thank you all for your help. My problem with accessing the fuel filter is that I have a sidecar attached which is a huge pain to remove. The sidecar has to be completely removed to get the panel off. Due to the modifications to the bike the kickstand is too big which was why it about fell over, even though I put it down. I just bought the bike a few months ago. I took the sidecar off, not long after I bought it to fix a heating issue I was having. My left leg was burning hot and turning red. I ended up removing front air baffles as someone suggested and velcroing the rubber flaps down. Anyways this bike has modified stuff for the sidecar that you can't ride it with it disconnected. It seems I only have the fuel issue during the beginning of the ride. Now I'm leaving the choke on full, until the gauge is closer to the middle. Since doing that I've been problem free. When I can get a helper I'll disconnect again and replace filter, plugs, etc. It's very hard to do solo. You have to literally pull the bike away to the left. And push/pull it back to reconnect. I've added a couple of pictures so maybe you can understand what I'm writing. Those links don't move whatsoever.

 

[Chrissn3]

If you increase idle by a 100 rpm would that keep the engine from stalling?

No. I tried many times.

 

[TerryS]

If the problem is stalling at low revs then I doubt it would be a fuel supply issue (i.e. blocked filter or restricted flow through the vacuum valve). Would expect that to manifest at higher rpm. My money is on blocked low speed jets, which would also be why you need to keep the enrichener on for so long on the warm up. John O's suggestion of Seafoam or similar plus new plugs sounds like a good first step.

 

[lomita]

Time for carb cleaning/overhaul. Engine hot domino effect of gunked up carbs, leaning out, fuel starvation. I admire the sidecar.

 

[CYYJ]

Chris:

There is an enthusiast in the American South - Canton, Texas, I think - who specializes in overhauling carburetors for V4 Honda motorcycles. Here's a link to a discussion that mentions his services: Recommendations for Carb cleaning service. I've never used his services, but I do recall reading good reviews of the work he does.

I believe he charges about $350 US for a complete overhaul and rebuild of the carburetor assembly - this includes complete ultrasonic cleaning, new parts, calibration, etc. You might want to consider pulling the carbs and sending them to him for an overhaul during the wintertime.

If you are interested in doing an overhaul yourself (personally, I think that is "where Angels fear to tread", simply because of the huge number of small parts and the specialized equipment and tools needed to do the job), here's a link to an article that describes ST 1100 carb rebuilding: Carb Removal and Rebuild ( ST1100 ).

But, before you go down that path, I suggest that you rule out a blocked fuel filter or partial failure of the vacuum operated fuel cutoff valve (see post # 9 above). I think those two items are the more probable causes. FYI I have a 2001 ST 1100 with over 130,000 miles on it, and the carbs work perfectly. Other than synchronizing them from time to time, they have never been serviced.

Michael

 

[CYYJ]

...I took the sidecar off, not long after I bought it to fix a heating issue I was having. My left leg was burning hot and turning red. I ended up removing front air baffles as someone suggested and velcroing the rubber flaps down.

Chris:

Here's an article about reducing heat on the ST 1100 that might be of interest to you. I embodied this modification on my ST 1100 and have never had any heat problems. It's a simple modification to do, just add one inexpensive part, no other work needed.

ST1100 - Solving the 'hot left leg' problem

If you can find a set of the OEM accessory side air deflectors and install them, that will also help reduce heat. The deflectors increase the low pressure zone around the side air outlets of the engine, just ahead of where the deflectors are installed, and that increases air extraction through the large side vents that fit over the camshaft covers. Those accessory air deflectors are long out of production, but you might be able to find a set at a salvage yard, or from someone who is parting out a ST 1100.

Michael

Side Air Deflector

 

[Chrissn3]

That's

Chris:

Here's an article about reducing heat on the ST 1100 that might be of interest to you. I embodied this modification on my ST 1100 and have never had any heat problems. It's a simple modification to do, just add one inexpensive part, no other work needed.

ST1100 - Solving the 'hot left leg' problem

If you can find a set of the OEM accessory side air deflectors and install them, that will also help reduce heat. The deflectors increase the low pressure zone around the side air outlets of the engine, just ahead of where the deflectors are installed, and that increases air extraction through the large side vents that fit over the camshaft covers. Those accessory air deflectors are long out of production, but you might be able to find a set at a salvage yard, or from someone who is parting out a ST 1100.

Michael

Side Air Deflector

Thank you for your help. That was the same article I read and did. Since doing 2 of the things as stated in my post, from that article, it hasn't been burning me anymore. I've looked for those deflectors, but haven't found. Thanks Honda. Lol.

 

[Chrissn3]

Set idle to spec, run a bottle of Seafoam or Techron through a tank, and replace the spark plugs w/Iridiums. FWIW

John

I added 2 oz of seafoam to the tank for that's all I had left. I can buy more if need be. I pulled one spark plug that was easily accessible and attached photos and I cleared out the gas cap vent. New iridium spark plugs are on order and should arrive next week sometime.

 

[Larry Fine]

Those are very sooty, as in too rich. You have the 'choke' rotated fully up and toward the clutch lever once warm enough to ride, right?

 

[Chrissn3]

Yes. I bought this motorcycle used on father's day of this year 2019.

 

[Deleted member 24046]

Wow, thank you all for your help. My problem with accessing the fuel filter is that I have a sidecar attached which is a huge pain to remove. The sidecar has to be completely removed to get the panel off. Due to the modifications to the bike the kickstand is too big which was why it about fell over, even though I put it down. I just bought the bike a few months ago. I took the sidecar off, not long after I bought it to fix a heating issue I was having. My left leg was burning hot and turning red. I ended up removing front air baffles as someone suggested and velcroing the rubber flaps down. Anyways this bike has modified stuff for the sidecar that you can't ride it with it disconnected. It seems I only have the fuel issue during the beginning of the ride. Now I'm leaving the choke on full, until the gauge is closer to the middle. Since doing that I've been problem free. When I can get a helper I'll disconnect again and replace filter, plugs, etc. It's very hard to do solo. You have to literally pull the bike away to the left. And push/pull it back to reconnect. I've added a couple of pictures so maybe you can understand what I'm writing. Those links don't move whatsoever.

Hi I have a chair on mine and you can flex the side cover out of the way enough to get to the bolts for the shelter I keep a short 10 mm box ratchet at hand to get to those bolts no need to unhook the sidecar sometimes I just unbolt the one brace nothing should come out of adjustment.just my 2 cents worth thx.

 

[Chrissn3]

I ended up successfully doing that yesterday. I did the fuel bypass yesterday and am going to put the new fuel filter in today, when it arrives, after work. I tried un bolting the top links for sidecar and motorcycle started to lean over so I said forget that and re put back on. I thought maybe if the bottom ones were still connected it'd be fine, but I was wrong. My next sidecar rig will have no modifications to the bike. When disconnected the bike just wants to fall over. That's craziness.