ST1100 Engine Knocking, Maybe

joebiker86

joebiker86

Joined
Jan 27, 2021
Messages
71
Location
Woodruff, WI
Bike
2001 ST1100A
So I picked up my 2001 ABSII a couple months ago and rode it about 2.5 hours back home. Bike only has 18k miles on it and has been sitting for quite a while. It's been in my garage getting a number of things installed on it (nothing mechanical - RAM mount, USB socket, Oxford grips, Honda voltmeter, Euro headlight housing/Morimoto LED's, Fuzeblock FZ-1, clip flip mod). I haven't ridden it anywhere else, need to bleed the brakes as the previous owner tried it and they are too soft for my liking. I started it up tonight just to run the engine a bit and there are noises coming from the engine that do not sound, or feel, like its happy. I didn't notice any of this when I rode it home, but it doesn't seem to do it at the rpms typically run on the highway. Over the winter I almost picked up a 98 non-ABS model with about this many miles that was doing the same thing. I passed on it with money in hand as I never heard that in any of my past 1100's make these mechanical noises, but it had also sat for awhile and it was damn cold when I started it up in a detached garage.

I did drop a bolt from the brake lever housing into the bowels of the bike that I still haven't located while installing Oxford's. Maybe it's just bouncing around the engine compartment, but I doubt it would sound like this. Wondering if anyone else has heard anything similar. The gas/treatment in the tank has been there for quite awhile, thought about detonation as well. Any ideas appreciated.

 
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Sounds more like detonation to me. I would drain the fuel and put fresh fuel in, with whatever fuel system cleaner you like. If it's been sitting with old fuel in it the fuel may have lost several octane numbers causing detonation. With only 18K, it's been sitting a lot, I certainly would change all the other fluids as well (especially the oil and filter). Never trust the PO on when the fluids were changed, unless they change them in front of you!
 
I know nearly nothing about the 11 or my own 13 but Ive had lots of lessons (school of hard knocks no pun intended) carbs and old gas especially ethenol blends might be the problem, ethenol blends can break down in as little as thirty days and correct me if im wrong anybody but even if the idle jets arent fouled you might have a lower than acceptable octane rating with whats in there. My quiet running two barrel 65 389 at 10.25 : 1 with points and condenser tells me no lies between 89 and 91 octane, but hard to know on anything else.
Recently I think I warmed up and idled worse on Shell 91 but Im 65% Chevron 94 now and about the same cold start ambient, so lets see...
How did I ever get like this? I gotta get out more.
 
Don't know what you consider quite a while but in spring time when my bike is started after a few, maybe 3 months there is some knocking and sputtering a short ride some fresh gas ands it's fine.
 
No diagnosis here. Just some random suggestions which have cropped up with my own STs. Take whatever snippets you want.

Screwdriver handle to the ear, probe around touching the blade on various parts of the engine eg inlet port, exhaust port, camshaft covers. See if you can identify where the knock is coming from.

Check the exhaust port bolts are tightened as they should be. Also check whether the 4 or 5 small bolts that hold on the heat shields on the exhaust headers are all present. Beware moving these shield bolts though, without first using penetrating fluid. Just check the shield in various places by 'twanging' the sheet metal. ( ie pluck the edge of the shield like a guitar string).

But I would start with new fluids. New synth / semi synth oil, filter, air cleaner. New plugs, correctly gapped and seated. Make sure the compression washer is not wedged on the plug threads at an angle. Check plug caps and HT leads for green corrosion. Ht lead will unscrew from the plug cap. Use silicone oil or grease to screw it back in. You may be able to slice off a small end of the HT lead to get to fresh copper but judge if that is possible to keep enough length. Plug cap resistance should be 5k ohms.

I would get high octane fuel in the tank; get some carb cleaner additive in; the fuel filter is easy to remove and check on the 1100; go for a run with higher than normal revs eg keep revs up to 4-5k rpm on fast open roads. It will suddenly start to spin much more freely after about 45 mins or so. Choose a day with fresh cold air - the engine always runs better with 'heavy' air - more oxygen and a bit of moisture. First thing in a morning before the sun heats up the day, is often good.

My 1100 always purred beautifully, but on some mornings when the engine was cold it would produce ticking noises (not loud enough to be called knocks) I imagined that it was coming from the camshafts, but the noise would disappear once the engine was warm and the choke was no longer needed. It sounded a bit like the noise that central heating pipes make when they are expanding / contracting.
 
I’m in agreement with the carb synch. When I cleaned my carbs on the 2000 years ago (it sat for a bit like yours). Once I re-installed the carb bank, it knocked like that. A carb synch fixed everything. Get a CarbTune or like tool. It’s actually very easy to do yourself, unless you want the shop to do it.
 
When I ride in town sometimes with my sun glasses on ( I know not very smart of me) I notice a lot more noises than I do when wearing my helmet on the Highway. Maybe you are experiencing this?
 
That sound happens when the mixture is too lean. Usually when starting up if the choke is turned off prematurely.
It could be caused by clogged ( or partially clogged) idle jets.
As others have suggested get new clean FRESH fuel into all parts of the fuel system. Drain the Tank, change the Fuel filter.
If it's only at idle, Get some fuel treatment like Techron in there and go ride it around for a few hundred miles.
If it doesn't clear you will need to pull the carbs and clean idle jets.
 
Thanks everyone for your feedback. Drained the tank as much as I could, then let it idle for an extended period of time. Finally got tired of waiting for it to be completely drained. Dumped in 5 gallons of premium 91 along with an appropriate amount of Seafoam. I had replaced the fuel filter this past weekend. Running significantly better now, sounds as it should. Do have an odd throttle response in that I can't hold it around 2k. I can move it smoothly from idle to 1500ish rpm, then watch it rev up to around 2700 rpm and higher. Will not sit in that gap between it. Will see if running the Seafoam though it helps with any jet crud I might have. Planning to go through the carbs and freshen them up this winter.
 
Erdoc48 said:
I’m in agreement with the carb synch. When I cleaned my carbs on the 2000 years ago (it sat for a bit like yours). Once I re-installed the carb bank, it knocked like that. A carb synch fixed everything. Get a CarbTune or like tool. It’s actually very easy to do yourself, unless you want the shop to do it.
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I do have a Carbmate I've used since one of my very early ST's. Will definitely be doing that shortly. Looks like the ABS/California models may have different carb connections than the non-Cali models?
 
jfheath said:
No diagnosis here. Just some random suggestions which have cropped up with my own STs. Take whatever snippets you want.

Screwdriver handle to the ear, probe around touching the blade on various parts of the engine eg inlet port, exhaust port, camshaft covers. See if you can identify where the knock is coming from.

Check the exhaust port bolts are tightened as they should be. Also check whether the 4 or 5 small bolts that hold on the heat shields on the exhaust headers are all present. Beware moving these shield bolts though, without first using penetrating fluid. Just check the shield in various places by 'twanging' the sheet metal. ( ie pluck the edge of the shield like a guitar string).

But I would start with new fluids. New synth / semi synth oil, filter, air cleaner. New plugs, correctly gapped and seated. Make sure the compression washer is not wedged on the plug threads at an angle. Check plug caps and HT leads for green corrosion. Ht lead will unscrew from the plug cap. Use silicone oil or grease to screw it back in. You may be able to slice off a small end of the HT lead to get to fresh copper but judge if that is possible to keep enough length. Plug cap resistance should be 5k ohms.

I would get high octane fuel in the tank; get some carb cleaner additive in; the fuel filter is easy to remove and check on the 1100; go for a run with higher than normal revs eg keep revs up to 4-5k rpm on fast open roads. It will suddenly start to spin much more freely after about 45 mins or so. Choose a day with fresh cold air - the engine always runs better with 'heavy' air - more oxygen and a bit of moisture. First thing in a morning before the sun heats up the day, is often good.

My 1100 always purred beautifully, but on some mornings when the engine was cold it would produce ticking noises (not loud enough to be called knocks) I imagined that it was coming from the camshafts, but the noise would disappear once the engine was warm and the choke was no longer needed. It sounded a bit like the noise that central heating pipes make when they are expanding / contracting.
Click to expand...
PO said he ran Catstrol MC oil through it earlier this year, but yeah, I plan to change the oil/filter so I know what I have. I did pull the plugs and found the PO put in the NGK iridium plugs around 14k miles. The PO was the only PO, so while I have rough maintenance records they aren't overly detailed.
 
red one said:
When I ride in town sometimes with my sun glasses on ( I know not very smart of me) I notice a lot more noises than I do when wearing my helmet on the Highway. Maybe you are experiencing this?
Click to expand...
I know what you're saying, maybe it was doing it when I rode it home with my helmet on, especially at idle. Most of the way home was interstate with very few stop lights/signs start to finish.
 
Sounds great, thumbs up for all of that effort, fuel turns to varsol so quick these days; glad you're making progress. I've got a bypassconfigurated tee where I'm actually completely draining my tanks on vehicles I don't run anymore, you gotta remember, gasoline is actually any combination of I dunno, 26 complicated CH chains, the old - "what's feeding your engine" takes on a whole new reality now.
 
That sound is not an engine knock, you have a carb issue. Probably carb cleaning needed, sync, check vacuum lines as a start. If your engine will not hold a constant engine speed then something is wrong. I'd also pull the plugs and check them as well.
 
bdalameda said:
St1100's engines will make a knock if you have one cylinder misfiring or not running due to carb issues or plugs/ plug wire issues.
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Interesting. My 98 is making a knock which goes away when the bike gets warm. But it also runs rough when cold due to what I believe to be dirty carbs. What is your experience with this. The knock can be heard as well as felt.

Thanks,

Rick
 
As soon as I get my Suzuki on the road I plan on cleaning the carbs on the Honda. I will synch them then. I just went through this with my RF900.
The bike runs very good. there's a hesitation off of idle that is very noticeable when the bike is cold. Gas mileage is good (47-49), and going down the road it runs perfectly. It's good to know it could be a carb issue and not some more serious engine problem. Guess I'll know for sure after I clean an synch the carbs.

Rick
 
Rick Fisher said:
As soon as I get my Suzuki on the road I plan on cleaning the carbs on the Honda. I will synch them then. I just went through this with my RF900.
The bike runs very good. there's a hesitation off of idle that is very noticeable when the bike is cold. Gas mileage is good (47-49), and going down the road it runs perfectly. It's good to know it could be a carb issue and not some more serious engine problem. Guess I'll know for sure after I clean an synch the carbs.

Rick
Click to expand...
You probably already know but if you're taking the carbs off and it hasn't already been done change the engine top hoses and elbows and the carb rubbers if original will be u/s.
It's not unusual for the 11's to be a little knocky, especially when cold.
Good luck.
Upt.
 
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