ST1100 High Speed Sputtering

mikezoccola1

Joined
Jul 28, 2009
Messages
4
Location
Maryland
Bike
1998 ST 1100
ST Riders:

I own a 1998 ST with about 20,000 miles. After a divorce a 3 years ago and associated transitions, I was unable to ride my steel horse for about 1 year.

The bike has progressively gotten worse with high speed sputtering (4th & 5th gears) and rates of speed typically greater than 45 mph.

Researching the website, I found Michael's string of communications to replace or bypass the fuel shut-off valve. I did both and neither helped alleviate the problem.

Now what? Wisdom and experience are needed!@#$%^&*(

Has anyone had a problem with high speed carboretor jets clogging such that it does not impact low speed?

Thanks for considering.

Take care.
 
Re: High Speed Sputtering

mikezoccola1 said:
ST Riders:

I own a 1998 ST with about 20,000 miles. After a divorce a 3 years ago and associated transitions, I was unable to ride my steel horse for about 1 year.

The bike has progressively gotten worse with high speed sputtering (4th & 5th gears) and rates of speed typically greater than 45 mph.

Researching the website, I found Michael's string of communications to replace or bypass the fuel shut-off valve. I did both and neither helped alleviate the problem.

Now what? Wisdom and experience are needed!@#$%^&*(

Has anyone had a problem with high speed carboretor jets clogging such that it does not impact low speed?

Thanks for considering.

Take care.
Click to expand...

I'm not one of the site experts but I'll give it a shot. First I would replace the fuel filter. Then I would go with sea foam in a tank of fuel to clean the carbs out. If that doesn't work then I would look at balancing the carbs.

Okay experts, now you can tell him the real fix :D
 
Re: High Speed Sputtering

Mike, it may not be the carbs at all. There have been similar incidences of "spluttering" in the higher engine speeds caused by the air filter, particularly the K&N filter WITH the Foam Sock fitted around it. Removing the sock cured the problem immediately.

If you have one of those, remove the sock and see how you go. If you do not have one, just remove the filter and run the bike without it for testing and see if that improves the performance from the motor.

Good luck,
Allan
 
Re: High Speed Sputtering

Bikedad said:
Mike, it may not be the carbs at all. There have been similar incidences of "spluttering" in the higher engine speeds caused by the air filter, particularly the K&N filter WITH the Foam Sock fitted around it. Removing the sock cured the problem immediately.

If you have one of those, remove the sock and see how you go. If you do not have one, just remove the filter and run the bike without it for testing and see if that improves the performance from the motor.

Good luck,
Allan
Click to expand...

FWIW, the bike does not run well without the airbox on, and, I suppose, may not run well without the filter but with the airbox on. I think it has to do with getting the correct pulses of pressure from the starting and stopping of the air stream with the opening and closing of the valves to assist other cylinders.

Bill
 
Re: High Speed Sputtering

docw1 said:
FWIW, the bike does not run well without the airbox on, and, I suppose, may not run well without the filter but with the airbox on. I think it has to do with getting the correct pulses of pressure from the starting and stopping of the air stream with the opening and closing of the valves to assist other cylinders.

Bill
Click to expand...

Yeah, I think its a bit of a dog without the filter, but it IS consistant through the full range of revs/gears, so should still be able to tell if the problem is eliminated. BUT I don't recommend running it like that. Especially if you live on a dirt road!:D A good clean filter is called for at all times, so if there is any doubt just go ahead and replace (or clean if you have the K&N). Then you will eliminate that possibility.

While you are at it, go ahead and change the fuel filter. On mine it is just an inline filter that you can get at any parts store for $6 or so. Put in a generous portion of sea foam and run a tank through it. See if it improves. Most likely will.

Had similar symptoms on another V4 Honda and it turned out a new set of plugs took care of the problem.

BTW, I'm almost NEVER in 5th gear at 45mph!:eek::
 
Re: High Speed Sputtering

All:

Thanks for the fine advice.

I neglected to provide background in the interest of objectivity, now of which resolved sputtering, as follows:
- replaced fuel filter
- ran many cans of carboretor cleaner through gas tank (it was not seafoam)
- inspected carbs - they appear fine
- replaced spark plugs with NGK's
- cleaned and oiled K&N replacement air filter element and outer foam sleeve
Thus, I intent to remove the K&N air filter outer foam sleeve from the K&N air filter and will get back for more direction. I also must find a retailer with seafoam and I'll give that a shot as well.

Incidentally, the sputtering problem begins to appear in 3 gear at over 5,000 rpm, then progressively gets worst in 4th and 5th gear. A wide open throttle in 4th or 5th results in total loss of power and the engine sputters along bearing maintainng the speed at which the throttle was opened up to full.

In 5th gear, a gradual, slow and consistent very slow opening of the throttle to full open will gradually increase speed without any sputtering; this makes me believe that the high speed jets are clogged.

I don't want to tear down the carbs because I reside in an apartment (no garage due to divorce) and of the time and expense. I sorely miss the high speed responsiveness.

Thanks again for the advice. I'll get back to you with results of your fine suggestions after the holiday.

Take care and ride safe.
 
Re: High Speed Sputtering

Hmmm, If it's not fuel and not air and you replaced the spark plugs. Maybe plug wires? If you put ST1100 in the title line John O and or George might chime in on this. Or if a Mod moved it to ST1100 tech.:shrug2:
 
Re: High Speed Sputtering

Have you tried by-passing the vacuum fuel petcock? A failing one will cause problems similar to what you describe. My first suspicion is that K&N filter with the outer foam layer. No one has gotten an ST1100 to run right with that configuration. Way too restrictive.
 
Re: High Speed Sputtering

Ah... you DO have the foam sleve on the K&N.. and recently oiled... take it OFF, that is all you should need to do to get your performance back.

wjbertrand has it right and plenty have tried. Many tears have been spilt on this little problem.
The solution has been the same in every case. Most go back to the stock Honda filter at the next change and, I believe, those can be cleaned and re-used although I have no first-hand knowledge of this.

Have fun,
Allan
 
Re: High Speed Sputtering

Hmmm, good advice so far. Sounds like you have most of it covered....Jeff is right, try bypassing the fuel valve, my death symptoms were like what you describe.

You next need to check all the vacuum hoses you can find, a small vacuum leak could be part of it.

Since you have tried the carb cleaner (seafoam is the best, IMHO. Autozone carries it), I'm going to guess that you have small holes in your carb diaphragms. Try everything else first, and get back to us....
 
Re: High Speed Sputtering

ST Owners:

I am fortunate to be part of a club that possesses experienced and adroit members.

Many of you advised to remove the foam prefilter on the K&N air filter, replace the spark plugs/wires, use SeaFoam, replace the gas filter, et cetera.

I've taken your advice and voila, you are indeed correct. My work was:

The plugs appeared normal, but the gaps were off. Replaced with NGK Irridium.

A new gas filter.

Removed the K&N foam filter.

A entire can of SeaFoam to the filled fresh-gas tank.

Spark plug wires existing; did not replace.

My guess is that it is the foam prefiler or the plugs. At some point I will verify which one and let you know.

For the record, the gas was fresh and the filter replaced last season. I bypassed the fuel stop diapham valve and still had the sputtering problems; I think the biker named Mike in Switzerland apprised us of his problem resolution by bypasssing the fuel shut-off valve; it did not help me.

What a pleasure to roll up the torque band, unhampered again.

Again, much appreciation. :):):)

Mike Z.
 
Congrats.
It might be just me; but, I'd put the vacuum valve back into the mix now that the bike is back running fine...

Mark
 
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