Seeking advise on leaning the mix

Brant · May 6, 2016

maubur said:
Thanks for the heads up on the colortune gadget! Never heard of that before. Do you have info on the plug size in mm for the ST? So, how exactly does it work? How can I relate flame color to mixture at idle and while synching carbs? Sounds promising.

Never mind. Saw a video on YT. Pretty cool. Still need to set screws while running and not useful to sync.

Never have used a Colo-Tune from Morgan, but having a Morgan Carb-Tune for syncing carbs is definitely worth having, and yes, I have and use one. They're made and shipped from the UK for just a bit over $100. I have compared its readings with my mercury manometer and it IS spot on! Morgan Carb Tune uses stainless steel slides and no fluid whatsoever....comes with a carry soft case so you can haul it stored anywhere. The idea of having a liquid free and extremely accurate manometer came about to me from being a long time member on xs11.com. The 4carb Mikuni carb bank on the Yamaha XS1100 is particularly finiky for setting things and tuning, as are all carbs, even Kiehns on our ST1100's. Has been well worth the week wait for shipping time!

Maubur, I totally relate to your logistics and was just trying to keep it simple for ya' without needing a lot of special testing equipment. A carb sync will unfortunately need the use of four vacuum gauges with restricors in the hoses ends such as un-used jets or such in order to nullify the needle fluttering or bouncing a bit. As far as idle mixture screws......an eighth of a turn one way or the other can and does make a world of difference in proper running and fuel consumption, and also a rich or lean cond. The other issue is the Morgan Colortune when used as instructed will leave each carb mixture screw an eight turn out, which is to rich. Set flame spark color as instructed.....then screw in mixture screw another eighth of a turn

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ST1100Y · May 7, 2016

Brant said:
...having a Morgan Carb-Tune for syncing carbs is definitely worth having...

Compared mine to the electronic VacuumMate at the w/shop once and the Morgan tool is spot on.

My thesis on using the Colortune is to first get the idle mix equal as good as possible on all 4 pots, before finalising carb sync.

I just ordered a kit (incl 10, 12 & 14mm adaptor) to check/confirm settings on my '00 ST1100 (and then on the CB500/4's...), since the exhaust reeks kinda rich plus I'm sensing unruly idle.

maubur · May 14, 2016

Ok. Another plug failed. Front right this time. That's a two week lifespan. I'd expect such a short lifespan to come with some smoking, be it caused by oil or fuel. Not my case.

Cleaning the filter didn't help either. Been looking for a pilot screw tool and aside from the Honda original, all aftermarket seem to be useless. There are people saying that even with the sensible tach and the original tool, the idle drop procedure is mainly an act of faith. The color tune thing seems more and more atractive.

Anyways, how can a pilot screw suddenly slip out of spec to the point of sooting plugs in a couple of weeks when the last set lasted almost a year? Maybe a float failed.

Sorry for asking rethoric questions. I know most of you are going to suggest I buy the tools and dig in and indeed, right you are.

Just looking for some moral support. Thanks!

ST1100Y · May 14, 2016

maubur said:
Ok. Another plug failed. Front right this time. That's a two week lifespan.

Chances you could post decent pics of the fouled plugs? Might aid circling down the source of trouble...

Jim Van · May 14, 2016

Jim Van said:
I doubt you can adjust the mixture screw out enough so the mixture will be so rich you don't need the choke to start. I think you have another problem besides the idle mixture screws being mis-adjusted.

maubur · May 16, 2016

Fouled No. 1 (FR) plug (aprox. one month since throroughly cleaned):

Very suspicious unburned oil smudge on the edge of the plug seat.

Jim. Choke has never raised RPM's on this bike. That's the last 13 years. Mayority of cold starts a blip of the throttle will do. Starts at the first spin. Hardly ever use the choke. IIRC screws are under 2 turns out and floats at 8mm.

Managed to recover two old gasalizer reports.

Back in 2012:
Temp ?C: 53.2
RPM: 1281
CO: 2.43 (<=4.50)
CO2: 11.0
O2: 3.2
Hydrocarbons - HC (Hexan): 399 (<=2000)
Nitrous Oxide (NO): 0.00

July 2015:
Temp ?C: 19
RPM: 1630
CO: 4.26 (<=4.50)
CO2: 8.3
O2: 5.93
Hydrocarbons - HC (Hexan): 1400 (<=2000)
Nitrous Oxide (NO): 0.00

Any ideas?

Thanks!

dwalby · May 16, 2016

can you tell if the plug residue is oil, or gasoline? I'm guessing gasoline. Given that you say the choke doesn't raise the RPMs, that's the first thing to look for, it sounds like your choke is stuck open.

if that's oil on the plug, then you may have other issues with oil entry into the cylinder like valve seals, rings, etc.

maubur · May 16, 2016

Could be either (or both?). Although shiny, it's dry to the touch. Smell is not conclusive. If it was only oil the bike would be smoking like crazy to foul it up that bad in a couple of weeks.

I seriously doubt I've been riding for 13 years on a stuck clutch. The exhaust analysis does show a much richer mix than back in 2012 and if rejetting is not an option, then I guess I'm stuck with tightening the idle mixture screw even further, lowering the floats into the bowls and synching. No advise on the needle clip setting queried on my first post, either.

dwalby · May 16, 2016

maubur said:
I seriously doubt I've been riding for 13 years on a stuck clutch.

the choke should have an effect on RPM, since yours doesn't, I'd try to understand that mystery first (if you haven't already ruled that out, not sure about the history of this thread).

Brant · May 16, 2016

dwalby said:
the choke should have an effect on RPM, since yours doesn't, I'd try to understand that mystery first (if you haven't already ruled that out, not sure about the history of this thread).

Hmmmm........been a few yrs. and he may have forgotten he lowered idle a few yrs. back.

What I'm leading to is to check the choke/enricher cable housing hold-down clamp on upper left side of motor. When that hold-down clamp for the housing works loose just a bit, cable housing slides a bit instead of cable itself, leaving choke un-knowingly on a bit. The reason I make this suggestion is I had this happen to my ST1100. It happened so gradually that I at one point I even lowered the idle a tad. Then by pure accident, one day while giving a glance under the Tupperware on left upper side of motor, that housing hold down clamp looked loose.......and sure enough it was. Slid housing back to where it SHOULD of been and tightened pinch clamp back down. Warmed up motor and re-set idle......all fine after that, even mileage came back up to its normal 50+mpg..........JAT and something to check!

DevonHondaMan · May 19, 2016

I have just stumbled upon this thread (I should be marking student's submissions, and am losing the will to live, so indulged myself in some diversionary tactics). My response is taken word for word from a post I submitted a few days ago, because my suggestion is relevant here, and similar to that of Brant immediately above. Here goes:

I had worse fuel consumption than I thought should be the case, and asked my mechanic to balance the carbs. When I picked up the bike, he told me that I owed him for a tin of floor paint! The problem had been that the chokes were sticking partially on; actually, quite a lot. He freed them all up, started the bike, opened the throttles and a whole load of **** shot out all over this workshop floor. He told me that I needed to take it for a bit of a blast to get rid of all the **** that had built up over goodness knows how long. It improved my consumption by at least 15% overnight, and then I realised that there had always been a whiff of petrol when I got off the bike. Of course, I couldn't smell it when I was underway. That job was back in Dec 2014, and it was an extra because I was concerned, ie not part of the normal annual servicing schedule. When he serviced the bike as per the schedule in July 2015, he noted that the choke mechanism was again partially stuck, although nothing like as badly as previously. I get in there every now and then and give it all a good squirt, and await his judgement in a couple of months as to whether or not they are still partially stuck. That may be an answer, although I realise that it may well be very wide of the mark.

Good luck!

Brant · May 19, 2016

DevonHondaMan said:
I have just stumbled upon this thread (I should be marking student's submissions, and am losing the will to live, so indulged myself in some diversionary tactics). My response is taken word for word from a post I submitted a few days ago, because my suggestion is relevant here, and similar to that of Brant immediately above. Here goes:

I had worse fuel consumption than I thought should be the case, and asked my mechanic to balance the carbs. When I picked up the bike, he told me that I owed him for a tin of floor paint! The problem had been that the chokes were sticking partially on; actually, quite a lot. He freed them all up, started the bike, opened the throttles and a whole load of **** shot out all over this workshop floor. He told me that I needed to take it for a bit of a blast to get rid of all the **** that had built up over goodness knows how long. It improved my consumption by at least 15% overnight, and then I realised that there had always been a whiff of petrol when I got off the bike. Of course, I couldn't smell it when I was underway. That job was back in Dec 2014, and it was an extra because I was concerned, ie not part of the normal annual servicing schedule. When he serviced the bike as per the schedule in July 2015, he noted that the choke mechanism was again partially stuck, although nothing like as badly as previously. I get in there every now and then and give it all a good squirt, and await his judgement in a couple of months as to whether or not they are still partially stuck. That may be an answer, although I realise that it may well be very wide of the mark.

Good luck!

So.......I assume you checked that the cable housing hold down on topside left of motor was nice and tight and not letting the whole housing slide when enricher/choke is applied or enricher only coming to a partial off position associated with cable itself?

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DevonHondaMan · May 19, 2016

No, it was the choke linkages that were seized rather than anything to do with the cable. They're not that easy to get to, even with the air filter housing removed, but after the mechanic's initial freeing of them, the occasional squirt with WD40 (do you have that across the pond?) appears to be sufficient to keep the whole mechanism moving as it should on both pairs of carbs. I can now see it all doing something, anyway, whereas previously, had I looked, it would just have sat there being stubborn and not moving, despite being urged to move by the movement in the cable. Getting in there with a good few squirts, as well aimed as possible, is unlikely to do much harm. In fact, a good visual check- in the dark, lights out, torch on - might prove whether or not the linkages are moving as they should when the cable is operated. Bon amusement!

dwalby · May 19, 2016

DevonHondaMan said:
the occasional squirt with WD40 (do you have that across the pond?)

of course we do, it was invented in San Diego. Its benefit as a lubricant is minimal, its a very light oil, but I guess the choke linkages aren't that demanding of their lubricant. Since you say "occasional squirt" I wonder if you used a better spray lubricant if you'd only need one application and be done with it. Just thinking out loud.

DevonHondaMan · May 20, 2016

Thanks for that, dwalby, I didn't know its provenance. I have more recently been using a silicone spray, originally for the curtain track in my motorhome as it would not mark the curtains with a bit of overspray, unlike the DW, but now used increasingly just about all over. I might give that a go if I need to and see how long it lasts.

maubur · May 24, 2016

Back after a nasty flu. Wasted weekend. The stuck choke theory is sounding more plausible, seeing I recently had to mess with the idle speed screw to compensate for a sudden drastic uncommanded idle drop. Hope to find time this weekend to check the plungers and linkage and maybe give it a WD40 bath from the outside (yeah, that San Diego juice is also available all over the place in Colombia).

My sister's trip down to Colombia is coming up and I have to get her to bring me something for the bike. I was thinking since I'm commuting about a mile four ways each day in cold weather and high altitude, and obviously have fouling issues on all four, maybe I could get her to bring me a set of hotter plugs? CR7EH9's - standard on ST1300 but not mentioned for the 11 - are currently at $26 for 10 plugs at amazon. My current Denso U24's are equivalent to the CR8's which will probably foul just as bad. Should I order the CR7's or are they too hot for this thing? Maybe I can add a universal carburetor synchronizer? The one that plugs into the snorkels one by one and measures vacuum? Can't find the default idle screw tool at either amazon or eBay, only sources my sister feels safe enough to buy from. Also, not sure how useful the tool is if I don't plan on getting a sensitive tachometer. For the moment, unfortunately, idle screw settings will continue to be hit or miss from the bench.

On another note, now that I think about it synching does nothing to correct a rich mixture. I've been hesitant to pull the carbs just because when plugs are clean, it's pulling strong and smooth. Mess with the synch and I may screw that up also. Back to square one. How do I lean without jetting when idle screws are at only 1.5 turns out and floats at 8mm? Needle clip? Anyone?

Thanks guys. Hope to hear back from you soon.

DevonHondaMan · May 26, 2016

If the issue is that the choke mechanism is sticking, you are permanently running rich, so freeing the chokes will immediately cure some, and perhaps all, of the rich running, meaning that you won't have a rich mixture to correct. The reason that I have highlighted this as a possibility is because I had exactly the same symptoms and so asked the mechanic to balance the carbs. He then identified the sticking chokes and so cured the problem simply by lubing. I am intrigued to see what the outcome is of your lubing the choke mechanism first - good luck!

Roger · Sep 17, 2016

A small diversion -
WD40 seems like a good lubricant - just for a little while - but it turns to sticky stuff in a warm environment... Trust me!
Also, the ST1100 was designed when fuel (IMHO) was rather better quality then than it is now. Could that have any bearing?

Roger

Brant · Sep 29, 2016

DevonHondaMan said:
If the issue is that the choke mechanism is sticking, you are permanently running rich, so freeing the chokes will immediately cure some, and perhaps all, of the rich running, meaning that you won't have a rich mixture to correct. The reason that I have highlighted this as a possibility is because I had exactly the same symptoms and so asked the mechanic to balance the carbs. He then identified the sticking chokes and so cured the problem simply by lubing. I am intrigued to see what the outcome is of your lubing the choke mechanism first - good luck!

.....gonna have to expand on that. I first suggest you check the cable housing mount associated with the choke(enricher). Top left side of moter is where cable mount located. If mount works loose, then the fixed cable mount housing has allowed cable to move or slip instead of totally operating the enricher portion as it should. This causes extremely low idle when cold(enricher not fully engaged), and also allows cable housing to slip, keeping enricher partly on when you think is completely off.........BTDT, and tightening down housing clamp, once you either see enricher control completely on or completely off

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