High idle when warm: 1991 ST1100

[scottincalgary]

Hey there,

I searched for this issue and found a whack of similar issues with ST1300s...but not ST1100s.

I just bought this 1991 with 19,000 miles on it. In beautiful shape and starts great although she's a tad rough at cold start and idle...likely the pilot jets.
I ran some carb cleaner and she's improved but now I'm finding that after a good long warmup ride in the foothills of Alberta...when I get back to the city she's idling up...around 2500 rpm.

Sometimes a throttle blip will bring her back down...but I don't want to blip her...I want her purrfect.

She looks like she's had some of the Steinborn mods as the air filter box has been drilled out on the sides and she has a K&N (I've cleaned and oiled).

Your learned insight is appreciated!

 

[c130flteng]

since you are looking at a bike that is 22 years old and has been operated an average of less than 1000 miles a year, I suspect this bike did a lot of sitting over time. Have you checked to see what the condition of your throttle linkage is? If there is a lot of gunk built up it could stick your throttle a bit. I would also look at the throttle cables to ensure they are not sticking as well.

Tony

 

[scottincalgary]

Hey Tony,

Checked out the linkage and the cables...they were all good and moving freely. Checked all the vacuum hoses...mother of God there's a lot a those! Have a hunch they may need replacing.

Just got back from a 1200 mile blast down to Montana and Idaho and never had a repeat of the high idle when hot. You're right...after 22 years and low mileage it likely needed a good blast. Worked like a Rolls Royce Silver Shadow and didn't use one teaspoon of oil.

I am one happy ST owner.

Thanks,
Scott

 

[FieSTa45]

It just shows you what will happen when you pick a great bike.

 

[whammst1100]

I had this same issue on my 2001 ST 1100 after rebuilding the carbs, new carb boots, new hoses, new fuel pump, etc. it turn out the carb holder was racked a bit and let in extra air whiched caused mine to idle around 2100 rpm. My bike had 33,000 miles on it but had sat for a year and a half. My local bike shop ( not a honda dealer) had my ready to go for about $75.

 

[scottincalgary]

I've been looking for an ST1100 for five years. My first posting on this forum was back in 2008 asking for advice about older versus newer years. I finally found the right bike and I am incredibly happy. I rode with a bunch of ST1300's and they're nice bikes but I think the ST1100 is sweeter. Besides...the ST1300's look way shorter and fatter. Long, lean and fast does it for me!

 

[scottincalgary]

I thought the premiere year of 1991 may be a mistake...first year models are known to have their issues...but I can't find any!

 

[c130flteng]

Glad to hear it is running better. These bikes like to be ridden and do not like to sit. Keep riding and it will keep purring. When winter comes, if you store it during the winter, this site has a lot of good information on the best way to winterize the bike so it will fire right up come spring.
Happy Riding

Tony

 

[Craig_st1100]

91 st1100 with 18k. I had same issues. Fuel pump, fuel filter, gas tank had crud in bottom of tank and was also leaking fuel. New plugs, carb jets and cleaning and you may get it running perfectly like I know have done. Mine was ridden 12k in 12 years but over the last 5 yrs only 2500 miles so you are probably in store for some restoration like I had to do. Prob needs fork seal kit too and check the lube in the rear wheel. SITTING is so bad for anything automotive. Why don't people understand this. Best of luck. Hope you got it fixed up already

 

[kiltman]

I thought the premiere year of 1991 may be a mistake...first year models are known to have their issues...but I can't find any!

Actually ST1100's came into the Canadian & European market in 1990 I'm pleased with mine as well

 

[scottincalgary]

I've only experienced it once since I logged issue. I have a hunch that it could be related to throttle cable, lube, etc. or the issues you identified. Tank is clean and no fuel leaks but I'm certain that gum abounds.

Our out of province inspection check fork seals thoroughly and mine was good but I know I'm certain that the shock oil could use change.

Did you change your timing belt? Both yours is mine haven't reached mileage point but that belt is over 20 years old.

 

[scottincalgary]

You're right KiltMan...I've never ever bought a brand new vehicle of any sort...so forget that my 1991 ST was actually available in 1990.
To date, I haven't found anything wrong with mine and given that my other rides are 1971 Yamaha XS650, 1978 Yamaha SR500, 1978 Yamaha XS750....the ST is almost brand spanking new. ...to me

Question...do you ride in a kilt?

 

[Doodaa]

Any Seafoam added here ?Worked wonders on my 83 shadow....takes a few tankfuls.

I've only experienced it once since I logged issue. I have a hunch that it could be related to throttle cable, lube, etc. or the issues you identified. Tank is clean and no fuel leaks but I'm certain that gum abounds.

Our out of province inspection check fork seals thoroughly and mine was good but I know I'm certain that the shock oil could use change.

Did you change your timing belt? Both yours is mine haven't reached mileage point but that belt is over 20 years old.

 

[kiltman]

You're right KiltMan...I've never ever bought a brand new vehicle of any sort...so forget that my 1991 ST was actually available in 1990.
To date, I haven't found anything wrong with mine and given that my other rides are 1971 Yamaha XS650, 1978 Yamaha SR500, 1978 Yamaha XS750....the ST is almost brand spanking new. ...to me

Question...do you ride in a kilt?

There was a 1990 model year for the ST1100, 91 was the first year the bike was introduced in the States and most parts available start at the year 91
(the States being the largest market I suspect)
And yes I do ride in a kilt (on occasion).... it makes forum member "Woodchuck" nervous .....

 

[Mark]

And yes I do ride in a kilt (on occasion).... it makes forum member "Woodchuck" nervous .

Filed under 'way TMI'...

 

[Brant]

Scott, run a couple more tanks of fuel with some Sea-Foam added.........bettin' it'll run like it should consistantly.