New-ish ST1100 Owner

DesmoRonin

DesmoRonin

Joined
Feb 27, 2025
Messages
21
Age
58
Location
Southern California
Bike
ST1100
Hello,

I've been lurking for a while and just registered to formally join the community :)

I bought a steal of a 1999 ST1100 with about 45K miles from my local dealer about a year ago thinking I was either going to flip it, rent it, or occasionally use it as camera bike. Here it is about 13 months later, and I'm enjoying it more than I thought I would, and it will most likely stay around for awhile. As a background, I have a few decades of riding experience on all kinds of bikes -- I used to assemble/PDI bikes for a dealer in the Mid-Atlantic region and even assembled the ST1100 when it was brand new. But most of my experience and mileage -- even sport touring -- are on dedicated sportbikes. Though I've ridden many larger bikes, I've never owned anything this large and heavy (and certainly not as comfortable). The bike isn't perfect, but seems pretty well-maintained. None of the issues that seem to be "common" with older ST's so far, and I will likely change belts and check clearances ahead of maintenance schedule.

Except... my tripmeter is currently shy of 150 miles, but my fuel gauge is not far above the empty mark. To be fair, I haven't paid much attention to fuel economy in the past, but it appears that I'm getting more than a little below 30mpg. I will get an accurate measure of this on next fill-up. The rear wheel spins freely, and there does not appear to be any drag anywhere. On this particular tank, I've done a mix of highway and around town riding with perhaps more stop and go than freeway. Is "low" fuel economy common for this kind of riding? I know the bike weighs 700 lbs., but I've read a lot of testimonials over the years that say above 40 mpg is more than common, and Fuelly seems to back this. Or am I just being a little over-zealous with my right wrist? For reference, almost all of my other bikes are very thirsty and *very* fast literbikes+. And while I don't ride like the hooligan I was in my youth, I'm not super gentle on the throttle either -- spiritedly, but not stupidly. Thank you in advance for your input, thoughts and sharing your experiences.
 
You should be able to get close to 300 miles or 500 kms per tank. It’s been awhile since I had an ST measured in miles so here goes.
If you filled the tank to the top, the needle on the gauge shouldn’t move until about 60 miles on the odometer. Then it will drop down at a pace. When the fuel light comes on you have about 1.5 US gallons and that gets you close to 60 miles. Around the halfway mark I think you should see about 150- 160 miles on the odometer, then it drops down fast.
That’s if you run 60 to 70 mph indicated on a GPS. If you run faster than that you will be burning considerably more fuel. Ethanol will also affect the mpg.
I get between 50-54 mpg ( Imperial. 4.6 L). You have a smaller gallon at 3.8 L so I guess 42 mpg US

You may need to have your carbs balanced. Keep in mind ABSII and California Standard models are jetted differently than the other 47 states. (Leaner). You will also have a charcoal canister by the kickstand.
Tire pressure will also contribute to your mileage results. I run 42/42. The recommended is 36/42

All the best.
 
The bike is averaging about 1800 miles a year. That's not many miles for an 1100. Have you run any carb. cleaner through it? Around here, Sea Foam is popular. I run synthetic watercraft 2 stroke oil every tank at 1 oz. per 5 gallons. This is suppose to help clean and keep the combustion chambers clean. All my 1100s have averaged pretty close to 40 mpg per tank. As mentioned above, when touring, I also have 160 miles on the trip meter when the needle is straight up vertical. Around town is a crap shoot on MPG. How often do you hit the rev limiter? The right wrist has a lot to do with MPG. I'm kind of a big guy. Getting 1000+ pounds moving quickly takes some gas but it is so much fun!
 
The timing belts on the ST1100 are engineered far stronger than you can imagine.
Age seems to have very little issue with the belts as I wait until they turned 100,000 miles before I changed mine - regardless of age.
Unless you just like to wrench and throw money at non-issues I'd skip the belt.
The mileage seems really low unless you spend a lot of time in high RPMS and wide open.
Do you smell gas fumes when it idles?
Will it idle smoothly (around 1,000 RPMS) with the choke (fuel enricher) off?
If not, your low speed jets are clogged.
 
I second Phil's comments on the timing belt. I did some serious rework on a 1991 that had spent 20 years garage parked, had only 17000 miles or so on the odometer. Given the parked history, I changed the belt just to ease my mind, as it turned out. I was surprised that it was difficult to distinguish the new belt from the old....no cracks, no evidence of wear. Definitely a better belt than our GL1000's design.
This one gets 'around' 40mpg on the highway. Like others have mentioned, around town mileage bites if traffic and riding habits get in the way.
 
If I might suggest, before doing any major maintenance items for example changing the timing belt. I would change all the fluids. The coolant, the hydraulic fluid for the brakes and the clutch. Utilize a chemical solution for cleaning the carbs before taking them off to clean, use an injector cleaner for at least three fill ups and see if that improves performance. Then if it has improved and you want to keep the bike, then you can consider the time and cost for replacing the belt, coolant hoses and elbows, and checking valve clearances and the like.
I believe you can inspect the timing belt without too much hassle.
 
kiltman said:
You should be able to get close to 300 miles or 500 kms per tank. It’s been awhile since I had an ST measured in miles so here goes.
If you filled the tank to the top, the needle on the gauge shouldn’t move until about 60 miles on the odometer. Then it will drop down at a pace. When the fuel light comes on you have about 1.5 US gallons and that gets you close to 60 miles. Around the halfway mark I think you should see about 150- 160 miles on the odometer, then it drops down fast.
That’s if you run 60 to 70 mph indicated on a GPS. If you run faster than that you will be burning considerably more fuel. Ethanol will also affect the mpg.
I get between 50-54 mpg ( Imperial. 4.6 L). You have a smaller gallon at 3.8 L so I guess 42 mpg US

You may need to have your carbs balanced. Keep in mind ABSII and California Standard models are jetted differently than the other 47 states. (Leaner). You will also have a charcoal canister by the kickstand.
Tire pressure will also contribute to your mileage results. I run 42/42. The recommended is 36/42

All the best.
Click to expand...
Thank you for your thorough reply! That's my concern. I've never run it until the fuel light illuminates, but I do remember a fill-up where the tripmeter showed around 175 miles, and about 5.5 gallons went in. I will look into getting a phone mount so that I can check my speedometer against the phone GPS. I often see my speedometer at 80 mph or slightly more indicated (a couple of mph over flow of traffic) so maybe that's part of the problem. I do have a non-ABS California model and have considered a less lean mixture and ditching the charcoal canister. Tire pressures usually hover in the 36 psi range. And I do have a carb sync tool that I've never used since ditching my mercury type, so I imagine it wouldn't hurt to check sync. Thanks again!
 
Obo said:
Maybe the gauge is off? Does it look "empty" in the tank at the 150 mile mark?
Click to expand...
I have no frame or reference other than the 5.5-ish gallons it took during a recent fill-up with 175 or so miles on the trip meter. It seems on the empty side, but not being that familiar with the tank level relative to the mileage indicated, I'm really not that certain.
 
Ron said:
The bike is averaging about 1800 miles a year. That's not many miles for an 1100. Have you run any carb. cleaner through it? Around here, Sea Foam is popular. I run synthetic watercraft 2 stroke oil every tank at 1 oz. per 5 gallons. This is suppose to help clean and keep the combustion chambers clean. All my 1100s have averaged pretty close to 40 mpg per tank. As mentioned above, when touring, I also have 160 miles on the trip meter when the needle is straight up vertical. Around town is a crap shoot on MPG. How often do you hit the rev limiter? The right wrist has a lot to do with MPG. I'm kind of a big guy. Getting 1000+ pounds moving quickly takes some gas but it is so much fun!
Click to expand...
I've only put on about 1,000 miles since purchase. Apparently, it belonged to an older gentleman (I'm old too, lol) who traded it in for a KTM Super Adventure. He did seem to be pretty good about maintenance and did most of it on his own I think. I tend to not run additives in my fuel... I do use quality fuel from high volume stations and sometimes even mix in some race gas so it doesn't go to waste. I don't know the previous fuel history of this bike though.

I ride about 50% or slightly more around town. That said, I rarely use my "wrist cruise control" for very long in an effort to keep myself away from distracted drivers here in SoCal. I don't hit the rev limiter often... power curve is a bit flat for my preferences, and I personally don't find any benefit in wringing it out on this bike. I'm an inseam challenged but fairly athletic 185 lbs., yet I do feel a little bit of helmet buffeting at speed unless I drop my head a little. I'm not crazy with my right wrist, but the ST is the heaviest and slowest of all of my current rides so perhaps I'm a bit more aggressive than I realize. To clarify, I'm not as concerned with my fuel economy as I am with the possibility of something not being right.
 
Uncle Phil said:
The timing belts on the ST1100 are engineered far stronger than you can imagine.
Age seems to have very little issue with the belts as I wait until they turned 100,000 miles before I changed mine - regardless of age.
Unless you just like to wrench and throw money at non-issues I'd skip the belt.
The mileage seems really low unless you spend a lot of time in high RPMS and wide open.
Do you smell gas fumes when it idles?
Will it idle smoothly (around 1,000 RPMS) with the choke (fuel enricher) off?
If not, your low speed jets are clogged.
Click to expand...
Thank you for your insight! I'm a decent wrench, and it looks like an easier job than replacing Ducati timing belts and no more difficult than a GL1500. I'll likely the change the timing belt when I have some spare time (never! haha). But realistically, I'll do it before the maintenance interval, and before I sell or give away the bike to a friend for the new owner's peace of mind.

I ride the ST spiritedly, but nothing crazy. No funny smells of any kind at idle or otherwise. When I first got the bike, the idle seemed to wander strangely enough. And I had it set at 1200 rpm (indicated) to mitigate this. Shortly afterwards, the wandering disappeared. Idle is not set at around 1,000 rpm... a little cold-natured during warm up, but otherwise fine. I'll still likely do some carb maintenance and possible rejet. Good time to change the likely rock hard intake boots, and I'll check the idle circuit/low speed jets while I'm there.
 
kiltman said:
If I might suggest, before doing any major maintenance items for example changing the timing belt. I would change all the fluids. The coolant, the hydraulic fluid for the brakes and the clutch. Utilize a chemical solution for cleaning the carbs before taking them off to clean, use an injector cleaner for at least three fill ups and see if that improves performance. Then if it has improved and you want to keep the bike, then you can consider the time and cost for replacing the belt, coolant hoses and elbows, and checking valve clearances and the like.
I believe you can inspect the timing belt without too much hassle.
Click to expand...
According to the dealer, the previous owner changed all of the fluids prior to trade-in. I'm a bit of a fluid snob, so I will change them again ahead of maintenance schedule to a brand I run in my performance bikes. I'll give the injector cleaner a shot, but I typically don't (nor haven't needed to) run additives of any kind. FWIW, I don't think that I'm having performance issues. I don't expect much more from a 700 lb. bike with a shaft-driven 100 hp. I do appreciate the advice! But I will inspect/replace all of those things anyways -- for myself and/or for the next owner.
 
Larry Fine said:
I suggest raising them both to 42. The handling should crispen up.
Click to expand...
Thank you, I'll give it a shot. Handling already seem sgood for a big, heavy bike. Pegs are a little too easy to scrape around bends though. And I may need to stiffen the suspension slightly as I get a slight wallow through unsmooth corners.
 
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