St1300 idle tick over problem

[easy rider]

Is it stalling at idle only, fine when opening up the throttle?

Once its got going its fine no issues when running its just that initial start up but then after a run you can come back and go back to it after its been left for a while then it plays up again. you can here it in the tick over it sounds off and this morning it started to shake and the idle was really rough its not happy.

This weekend going to get the vac hoses checked and 5 way T might even replace map sensor and coolant sensor as i have spares on hand. So disappointed with it i bought it to replace my old 136 k miles ST1300 and this was fine at first then suddenly this started happening.
It does seem to be now the temperature has got warmer outside, I do know if there is anything in the vac hoses that when the bike heats up and cools it can effect how that melts and sits in the lines which can mean different running situations. It can't be serious as it would not run fine when warmed up and full running. Below the air box is the only place we have not checked on this bike so will see what we find.

Things to check -

Vac hoses & 5 way T
throttle body sync
check wires on throttle body
Check linkage is ok
Map & coolant sensor ( I have them so can't hurt )
Check the 4 round throttle body rubber boot seals for cracks or signs of drying out as although low milage it is still 13 years old and has been sitting around a lot over the years.
These were built to ride and some people just get them for summer only so only small milage while I ride all year so it will get run regular when it runs.

Take it from there i guess

Best wishes

Martin

 

[easy rider]

On way home now would not hold idle when stopping at traffic lights had to hold throttle open then after a short run settled and holding idle. No I am home it will probably be the same after sitting for an hour or so.

 

[MidLife]

Once its got going its fine no issues when running its just that initial start up but then after a run you can come back and go back to it after its been left for a while then it plays up again. you can here it in the tick over it sounds off and this morning it started to shake and the idle was really rough its not happy.

This weekend going to get the vac hoses checked and 5 way T might even replace map sensor and coolant sensor as i have spares on hand. So disappointed with it i bought it to replace my old 136 k miles ST1300 and this was fine at first then suddenly this started happening.
It does seem to be now the temperature has got warmer outside, I do know if there is anything in the vac hoses that when the bike heats up and cools it can effect how that melts and sits in the lines which can mean different running situations. It can't be serious as it would not run fine when warmed up and full running. Below the air box is the only place we have not checked on this bike so will see what we find.

Things to check -

Vac hoses & 5 way T
throttle body sync
check wires on throttle body
Check linkage is ok
Map & coolant sensor ( I have them so can't hurt )
Check the 4 round throttle body rubber boot seals for cracks or signs of drying out as although low milage it is still 13 years old and has been sitting around a lot over the years.
These were built to ride and some people just get them for summer only so only small milage while I ride all year so it will get run regular when it runs.

Take it from there i guess

Best wishes

Martin

Rough idle can also come from the mixture being too rich at idle, which could possibly come from a pressure regulator not sensing vacuum and not opening up to bypass more fuel while idling.....like what a clogged vac hose or T might cause.....

 

[easy rider]

Rough idle can also come from the mixture being too rich at idle, which could possibly come from a pressure regulator not sensing vacuum and not opening up to bypass more fuel while idling.....like what a clogged vac hose or T might cause.....

I hope its something simple like a clogged T or vac hoses, idle is very jumpy and stutters when you go back to it after its been run then left to sit, I managed to lift the tank tonight and removed the fuel tank breather hose and blew air through it to check its clear. So the weekend will be the point we know as going under the air box is the only place we have not been since i bought the bike. I have a new pressure regulator on my old St1300 as well as new idle air control valve , coolant and map sensor are also available as i over hauled my old ST1300. So will work my way through all that after checking vac hoses & T plus a throttle body sync. Will keep you all updated. Started up my old St1300 tonight and she runs perfectly bit smokey at first and i had a panic as it had FI light for IAT sensor 9 flashes which was because i forgot to plug it back in after swapping it from my new ST1300 so its all good.
Must try and get that u joint replaced on it as even with 136k on the clock she still sounds great, shame about my new ST1300 hopefully get some answers this weekend fingers crossed.

 

[easy rider]

Work has begun the bike seems to be missing at low revs rough idle in warmer weather and when bike is warm after riding left to sit starts with rough idle and stall starts missing at low revs. Doing vac lines 5 way T checking throttle body boots plus stater valve sync. Inspect area under throttle body.
Take it from there and report back to you all
Fingers crossed

 

[easy rider]

No blockage in 5 way T replaced hoses with new plus replaced the T carried out throttle body sync swapped out Map sensor.
See what happens I guess. We did notice one of the valves was more dirty with carbon the other three were clean so possibly a faulty injector. So swapped injector over to see if the issue moves to the other valve when it’s next in. Keep you updated everyone

 

[MidLife]

No blockage in 5 way T replaced hoses with new plus replaced the T carried out throttle body sync swapped out Map sensor.
See what happens I guess. We did notice one of the valves was more dirty with carbon the other three were clean so possibly a faulty injector. So swapped injector over to see if the issue moves to the other valve when it’s next in. Keep you updated everyone

Did you try to idle with the vacuum line to the regulator disconnected (and plugged)?

That should lean out your idle mixture and maybe help diagnosing a mixture/injector issue.

 

[easy rider]

Did you try to idle with the vacuum line to the regulator disconnected (and plugged)?

That should lean out your idle mixture and maybe help diagnosing a mixture/injector issue.

Will pull injector off my old ST1300 if needed
Along with the pressure regulator.
It was not me doing it so I doubt they checked that. The weather is colder today so good chance it’s starting fine because of that,
Not getting too excited just yet, we have the parts just a case of swapping out as we work through each issue I guess.

 

[easy rider]

Hi All

Well I think I can safely call it now I was holding off because in traditional fashion the minute you say its all good things usually go wrong again.
It looks like the combination of replacing all the vac lines the 5 way T along with the MAP sensor followed by a throttle body sync has done the trick.
I also run two tanks worth of system cleaner through it to hopefully give the injectors a good clean and yes she is running and ticking over just as she should.
Really pleased as we are now 12 days clear with perfect starts at a full range of temperatures between 0 degrees c and above 12 degrees c riding every day and starting up at different points and riding.

Thanks everyone here's to just enjoying the ride again!

 

[SupraSabre]

When I bought my 2010, back in 2013, it had a similar problem. Wouldn't hold an idle, but also, it was hard to restart once it was warmed up and turned off.

I determined that it was the waxed assembly. After replacing it, I didn't have anymore issues with it during idle.

 

[easy rider]

When I bought my 2010, back in 2013, it had a similar problem. Wouldn't hold an idle, but also, it was hard to restart once it was warmed up and turned off.

I determined that it was the waxed assembly. After replacing it, I didn't have anymore issues with it during idle.

Did you have to make any adjustments with the wax valve or did it go straight in.
Only reason I ask is my old st1300 had a new wax valve but it was well out. When you get an st1300 factory set it warms up and it’s 1000rpm bang on one bar temperature. My old bike would rev high hot or cold and hit two bars temperature to idle.

Just wondered because after that unless I really have to not touching wax valve as it was a nightmare, warm up was never the same again.

My new bike is now over two weeks still running fine thank god.

 

[SupraSabre]

Did you have to make any adjustments with the wax valve or did it go straight in.
Only reason I ask is my old st1300 had a new wax valve but it was well out. When you get an st1300 factory set it warms up and it’s 1000rpm bang on one bar temperature. My old bike would rev high hot or cold and hit two bars temperature to idle.

Just wondered because after that unless I really have to not touching wax valve as it was a nightmare, warm up was never the same again.

My new bike is now over two weeks still running fine thank god.

Because I had bought some throttlebodies off eBay, I used one of those throttlebody's wax valve, so I just installed it without having to make any adjustments.

Of course, you do need to remove the throttlebody to get to it. PIA

 

[Igofar]

You should NOT try and make any adjustments on the idle wax valve regardless of what fools on the forums and YouTube videos say.
If you change the settings, it will just screw something up elsewhere.
The number one cause for the high idle that I have found, is the plastic black barrel, that is held by two little arms, gets dirty, and sticks, or the theads on the rod catch on the edge of the hole, binding things up and pulling the idle wax rod.
It is just MY belief that folks that changed the Idle wax assembly, in an attempt to correct the issue, simply "freed up" the barrel that was sticking without knowing it.
Keep this part clean and lightly lubricated and you won’t have any issues.

 

[TerryS]

I agree about the wax unit adjustment! I had to free up seized starter valves on my VFR800, very similar set up to the 1300. In the process I lost the factory setting for the "unadjustable" starter valve and had to get it back to the correct cold idle speed which took a few iterations to get the cold and hot rpm settled, otherwise I ended up with a fast idle that only settled back too close to the thermostat opening temperature, or the fast idle dropped too soon and gave a lumpy low idle. There is a definite relationship between how far open the SVs are on their shafts, and the position that they are held to by the cold wax unit.

 

[easy rider]

Well here we go again it’s now started to miss slightly at idle again last couple of mornings and the fuel pump is not priming intermittently but it got worse today. Turn ignition on no FI light cranks no start then intermittent it will prime FI light come on goes off as normal but then it runs then cuts out.
Changed out fuel cut off relay changed bank angle relay no fix possibly need to check sensor I then disconnected side stand still no fix. It’s just been recovered to the garage as i got stuck at the roadside it's starting to become a nightmare this bike.
Though with the FI light not always coming on when the ignition is turned i have my suspicions about Bank angle or kill switch as something is not just cutting the fuel pump its cutting the FI as well. un plugged fuel pump on my old bike and turned on ignition and FI light still comes on and goes off so it may not be the pump. See what the garage comes up with.