Help - Running rough

[steveboot]

Just picked up a 2002 ST that had been sitting for a long time. And she is running rough. When I got her she wouldnt idle without the choke on full. As soon as I got her home I opened her up and replaced the air filter (really nasty with evidence of mice being present...) and found the idle adjust was completely unscrewed... Got that back and she now needs choke to start but will idle on her own after a little warm up. However, she still stumbles/surges as soon as the revs get above about 4k. I've run several tanks of gas with sea foam through her and there has been some improvement, but she is still not smooth.

My probelm, no garage space. Any repair I undertake is out in my parking lot... So to pull the carbs for a good cleaning just doesn't seem like a good idea.

Any suggestions? A better method for getting carb cleaner into teh cars without disassembling everything? I remember as a kid squirting Gumout into a car's air cleaner to some effect. Is that a reasonable thing to do with an ST?

By the way, my local Honda shop says to clean the carbs will be at least $800 (but first I had to tell them the bike was not fuel injected...). I don't have a lot of faith in them.

Any help would be greatly appreciated.

BTW, the bike and I are in Bel Air, Md, if someone knows a shop that really knows ST's.

 

[SupraSabre]

I take it is a ST1100 with carbs. If you don't want to remove the carbs, you might not get the problem resolved any other way. But what I would do is to continue to run seafoam in it and just get out where you can ride it hard and see if "maybe" the carbs wuill clear themselves.

Back in 1995, I boulght a V45 Sabre that had been sitting for several years. I cleaned the carbs a couple of times, but not a as good as they needed. I rode that bike for a few years, put 21,000 miles on it and never did have those carbs clear out! I sold that bike to my brother and he rode it for several years while doing his 160 mile a day commute and they cleared out for him after awhile! So there is a possibility they can clear out that way. They didn't clear out for me because I didn't have that long of a commute. 4:

 

[mznyc]

You can do what I did and rent a garage locally so you can do the work as I was out of room in my sheds.You could pull them ,pull jets and clean them and check for diaphragm failure.Seems like most carb problems are clogged jets and cracked diaphragms(about $400.to replace).I found a set of glean carbs on Ebay for $100.You could also send them off to a known qualified carb rebuilder and you will essentially have new carbs when returned.Mike Nixon,probably THE Honda carb expert in the US,http://www.v4hondacarbs.com/details.html. $375.00,about half of what your shop is charging(ya, you'll have to pull them) and he knows your bike is carbed I have his book and it's fantastic.

 

[ST1100Y]

Long grounding times are never ideal for internal combustion engines...

I'd flush the tank to get all the stale gas and debris out, dunno if carb cleaning is a must but can't promise that any added fuel cleaner will solve the issue either, check for vacuum leaks (hoses, auto fuel valve, PAIR pumps/plumbing, carb boots), valve check, carb syncing... plus whatever surfaces while working on the bike, oil, coolant, brake fluid, tires, bearings, coolant hoses, etc...

 

[vinny]

You could pull the breather box cover off and spray some carb cleaner into the snorkels while running the engine. If the jets are pretty dirty/clogged, then it may take a bit. Try a couple of cans and see if you notice a change. If there is not much of a change, pulling them and taking them apart will be the best method.

 

[Doodaa]

If you don't want to remove the carbs, you might not get the problem resolved any other way. But what I would do is to continue to run seafoam in it and just get out where you can ride it hard and see if "maybe" the carbs wuill clear themselves.

I'm in the same camp. I've had success with an 83 Shadow that took more than a few tanks with Seafoam before it cleared. Without a place to work on it, I'd run it for the summer and see if it doesn't improve. Unless it gets worse, worry about this coming winter, when you'll be looking at some down time and protection from the elements.

 

[mznyc]

You could pull the breather box cover off and spray some carb cleaner into the snorkels while running the engine. If the jets are pretty dirty/clogged, then it may take a bit. Try a couple of cans and see if you notice a change. If there is not much of a change, pulling them and taking them apart will be the best method.

You'd be taking a chance destroying O-rings and other rubber parts like the diaphragms running carb cleaner through a set of carbs.The only way to truly give a set of carbs a cleaning is dis-assemble them clean all the metal parts with carb cleaner and replace all o-rings.This may not be the needed to fix your problem Steve,probably just clogged jets.If Seafoam doesn't work and all the easy checks don't find anything you'll have to pull the carbs,not that big a deal.

 

[vinny]

You'd be taking a chance destroying O-rings and other rubber parts like the diaphragms running carb cleaner through a set of carbs.The only way to truly give a set of carbs a cleaning is dis-assemble them clean all the metal parts with carb cleaner and replace all o-rings.This may not be the needed to fix your problem Steve,probably just clogged jets.If Seafoam doesn't work and all the easy checks don't find anything you'll have to pull the carbs,not that big a deal.

Your right, that is the best way! I was just saying it may be worth a try before pulling the carbs. BTW... thanks for the link to the V-4 Carb guy... that's a keeper.

 

[mznyc]

Your right, that is the best way! I was just saying it may be worth a try before pulling the carbs. BTW... thanks for the link to the V-4 Carb guy... that's a keeper.

What's great about Mike's book,not only is it informative,he is accessible by email if you have questions.The book is not specific to the ST carbs but the V-4's(VFR,Sabre,Magna) of the 80's and 90's but very similar to the ST's.Best $20 spent if you want to learn about your carbs from an expert.

 

[steveboot]

Thanks folks. This weekend I'll take her apart a little more and see what I find. Fromthe link to Mike's website, there is a simple test to see if the problem is due to carburetion. Essentially, change the conditions of the airbox to restrict or open up the air flow, and if there is a marked change, the problem is carburetion. Not sure that is 100% correct, but will at least fiddle with that to see.

Also of note is I checked my plugs and one was fouled (all others were a pretty grey/tan). Not sure what that is telling me, but I cleaned it up and will check it again after running it for a bit. Maybe swap plugs around to see if it's the plug itself or something else.

 

[Brant]

You'd be taking a chance destroying O-rings and other rubber parts like the diaphragms running carb cleaner through a set of carbs.The only way to truly give a set of carbs a cleaning is dis-assemble them clean all the metal parts with carb cleaner and replace all o-rings.This may not be the needed to fix your problem Steve,probably just clogged jets.If Seafoam doesn't work and all the easy checks don't find anything you'll have to pull the carbs,not that big a deal.

Spray carb cleaner, not even Berryman's B-12 chemtool affect the o-rings in question. Only carb DIP that WONT affect o-rings is Yamaha's carb dip. Carb bank soaked in PineSol(original, no copies) works with no damage to orings either.....still gotta disassemble first tho, bowls, jets, emulsion tubes, etc. Electrolisis using pine Sol is the ultimate clearing. NOT to be used with regular carb dip though cause in bout 4hours you'll be able to pour your carbs into a coolaid jug!

 

[steveboot]

So what would it mean if in neutral she seemed to run smoothly through the rev range but she bogs down and surges under load?

 

[Brant]

IMO, hasn't had enough decades of element exposure quite yet so suspect an electrical/ignition issue. From sounds of filter cond., the carbs below can't be much better.
Run smoothly through the rev range while in nuetral means to me that was a gradual throttle roll-on.
Warmed up and throttle snapped wide open from idle in nuetral may give you an entirely different scenario. Either way, the idle/pilot circuit and at the least, the pilot jets are plugged.

 

[steveboot]

bit by bit I check it out... #1 plug is fouling wet. swapped plugs around and it is always associated with the #1 cylinder. swapped the internals of the plug boot (contact and resistor?) and same thing. Today will see if swapping plug wires around will make a difference.

 

[Doodaa]

If swapping the plug wire doesn't change the plug that's fouling, try switching the coil end locations. I believe you have it narrowed down to ignition spark problems and since this is a "waste spark" firing, the coil fires both plugs at the same time. Knowing this, you can determine if you have a defective coil or spark plug wire/connection.

 

[steveboot]

Hmm... how do you get to the coil end without pulling the carbs? I had her pulled apart pretty well but couldn't get access to the coil side.

 

[Doodaa]

Never had this problem on this model, a few others had. Maybe one of those can chime in ?
All I can find for you is http://www.partzilla.com/parts/search/Honda/Motorcycle/1996/ST1100+AC/IGNITION+COIL/parts.html

 

[steveboot]

looks like the ignition wire to the #1 cylinder. After swapping front to back and then side to side, the fouled plug followed the wire. Now I have new wires on order and will post out the result when I get them.

For anyone interested... I found out the hard way there is an easy way to get at the coils. After pulling almost all of the plastic off the bike I finally got a view of them. If you pull the airbox you can see the top of the bracket that holds the coils (its brass colored). After you disconnect all the wires going to them, you can wiggle the coils up through the opening in front of the airbox.

No need to pull off more than the side panels, tank shroud, and airbox.

 

[Craig_st1100]

I am hoping you got this resolved. I had a similar issue: 91 1100 w/17k
prev 5 years bike only saw 700 miles total
fuel pump
fuel filter
tank had pin hole leaks (cheap Honda metals back then) Solder fixed that up after sandblasting and a sealer coat inside tank
carbs had to be redone
hoses replaced

What a mess and lots of work. If I would have taken this to a shop it would have been more than the bike was worth, so with forum help and an in-person assist from Juddspaintballs it is all straight now. Runs like bandit and starts right up every time.