ST4S - Soul destroying issues of getting it to start
- Thread starter Keith_henson
- Start date
That was my exact thoughts after some brain lubricationHmmmmbaffles. Backpressure?
So an update after a bloody good thrash on the st4s today, a good 160 ish miles covered in Wales and Shropshire (fuel limited as I wasn't stopping!). I think I used 6th once and she definitely goes like a train and sticks like my 748 to the road in the corners. Absolutely cracking piece of kit. Downside, my 12 year old son and his stomach...
Son: "Dad, can we stop for lunch on the way?".....
Me: "Nope nope and nope. Get your bacon and egg sarnie in you and get on the bike as I don't know if it will start again when hot"
Son:"but dad, we are going out over lunch and I'll get hungry and you said about dinky's"
Me: "get scoffing and get on the bike I've changed my mind
"
Needless to say he was not best pleased he was missing his hobbit style eating menu. When we got home he stood there when the engine was turned off and said "dad, that Duc is awesome. As comfortable as the ST2 and goes like the 748, can we do that again? "
I think I have a not so mini me in the making
Hope you all have a cracking weekend
Son: "Dad, can we stop for lunch on the way?".....
Me: "Nope nope and nope. Get your bacon and egg sarnie in you and get on the bike as I don't know if it will start again when hot"
Son:"but dad, we are going out over lunch and I'll get hungry and you said about dinky's"
Me: "get scoffing and get on the bike I've changed my mind
" Needless to say he was not best pleased he was missing his hobbit style eating menu. When we got home he stood there when the engine was turned off and said "dad, that Duc is awesome. As comfortable as the ST2 and goes like the 748, can we do that again? "
I think I have a not so mini me in the making
Hope you all have a cracking weekend
I’m so glad the issue is resolved and so glad your son is hooked 
Evening all,
A small update on the ST4S after a week or so. She was still being an absolute tw*t at starting, especially when cold. Sometimes yes, most of the time no. Needless to say muchos cussing in the garage. I was either thinking sprag, starter or ecu (the latter being more preferable)
In conversation with ChrisW, he pointed me at a replacement ECU on the Bay of E for the bluestreak one I had, he sent his address for me to send it to for some dark voodoo and it arrived back this lunchtime. This evening I went through the usual pain for fairing removal (getting well versed at that), nice easy ecu swap, reconnect everything, remove airbox lid, turn the key and boom. Alive in three chugs (as i say for my st2) with the DP exhausts on!!!!! Bet my neighbours thought i was mad having a little jig on the drive with a tin of ale in my hand.
Mentions of the TPS have been made, but thats after the next service. I am now going to put some miles on it (it only has 8300 after 20 years) and fit the panniers to it (bloody bolt holes are a mil or so out so I cant get them in!. Thats the next job (on another thread).
Many thanks to everyone for your help, certainly a learning curve and if anyone is coming through Shropshire (Much Wenlock) please come and pop by. The beer is always cold and the braai always lit.
A very happy Keith (and 12yo son!)
A small update on the ST4S after a week or so. She was still being an absolute tw*t at starting, especially when cold. Sometimes yes, most of the time no. Needless to say muchos cussing in the garage. I was either thinking sprag, starter or ecu (the latter being more preferable)
In conversation with ChrisW, he pointed me at a replacement ECU on the Bay of E for the bluestreak one I had, he sent his address for me to send it to for some dark voodoo and it arrived back this lunchtime. This evening I went through the usual pain for fairing removal (getting well versed at that), nice easy ecu swap, reconnect everything, remove airbox lid, turn the key and boom. Alive in three chugs (as i say for my st2) with the DP exhausts on!!!!! Bet my neighbours thought i was mad having a little jig on the drive with a tin of ale in my hand.
Mentions of the TPS have been made, but thats after the next service. I am now going to put some miles on it (it only has 8300 after 20 years) and fit the panniers to it (bloody bolt holes are a mil or so out so I cant get them in!. Thats the next job (on another thread).
Many thanks to everyone for your help, certainly a learning curve and if anyone is coming through Shropshire (Much Wenlock) please come and pop by. The beer is always cold and the braai always lit.
A very happy Keith (and 12yo son!)
Just possibly. It maybe next weekend to the Quatt food stop outside of Bridgnorth or Dinky's dinah depending where he fancies. Maybe both depending on his stomachLooks like it is Father/Son bacon butty trip this weekend
I love a happy ending... 
Nice onr, can't beat a 3 chug start 
I will let you know this weekendI love a happy ending...
Ever so glad you seem to have nailed it ....... that Chris is frighteningly good, isn't he?
However, if you get any more intermittent starting problems do take a look at the Crank Position sensor. I once had a complete refusal and went through all the usual, fuel filter etc, to no avail.
Eventually decided on the CPS and went to order the correct Fiat Tipo part, which meant checking the connector into the loom ..... so I tracked it down, broke it and compared to the picture of the Fiat part. Stuck it back together again, thought I'd just try the starter buttom and boom, immediate start up.
I've had a few times when it's not wanted to start, usually outside a pub when the entire beer garden is watching, and giving the CPS connector plug a wiggle does the trick.
You might want to clean the starter motor out sometime too, they get full of dust and shit.
And you're right, they make brilliant undrcover sports bikes .... even better with a large topbox stuck on the pillion seat, that really upsets the Pantigirdle brigade.
However, if you get any more intermittent starting problems do take a look at the Crank Position sensor. I once had a complete refusal and went through all the usual, fuel filter etc, to no avail.
Eventually decided on the CPS and went to order the correct Fiat Tipo part, which meant checking the connector into the loom ..... so I tracked it down, broke it and compared to the picture of the Fiat part. Stuck it back together again, thought I'd just try the starter buttom and boom, immediate start up.
I've had a few times when it's not wanted to start, usually outside a pub when the entire beer garden is watching, and giving the CPS connector plug a wiggle does the trick.
You might want to clean the starter motor out sometime too, they get full of dust and shit.
And you're right, they make brilliant undrcover sports bikes .... even better with a large topbox stuck on the pillion seat, that really upsets the Pantigirdle brigade.
A bit of an update (a good one). So in replacing the ecu, I decided it was time the bike had an oil and brake fluid change as they had not been changed since 2008 
Anyway, the bikes only done 200 miles in 13 years with the previous owner, so have done a 170 mile blast from darkest Shropshire to darkest Cambridgeshire this afternoon..... And what a bike! My god it goes like a train and then some. And a smile so large on my face the internal sun visor stopped people being blinded as I went past.
So so different in nature to my ST2 and 748.
A very happy Keith
Anyway, the bikes only done 200 miles in 13 years with the previous owner, so have done a 170 mile blast from darkest Shropshire to darkest Cambridgeshire this afternoon..... And what a bike! My god it goes like a train and then some. And a smile so large on my face the internal sun visor stopped people being blinded as I went past.
So so different in nature to my ST2 and 748.
A very happy Keith
And an update on the troublesome st4s......bloody starter motor has shat itself when I went to turn it over for the first time since winter. Solenoid clicks, battery voltage doesn't drop when I press the start button. It was starting to be a royal PITA in turning over towards the end of last year and I had a feeling this was the issue. Oh and the front brake switch is jammed on.....This bike was sent to test me!
I will let you know how it goes. Any pointers for taking the stator casing off and getting to the three bolts inside that hold the starter to the main engine case?
A very pained Keith
I will let you know how it goes. Any pointers for taking the stator casing off and getting to the three bolts inside that hold the starter to the main engine case?
A very pained Keith
I could well be wrong as I am comparing it to a very similar situation on a car. But,
Daughters car was doing exactly that, had a new starter motor fitted and made no difference. Turned out to be a bad connection.
I would check connections are all good first, especially the Earth.
(Sorry if you already did just that).
Yes, earth connection if hot starting is an issue - as the temperature increases so does the resistance, check and clean all connections.
As for removing the starter motor I've not had to contemplate that one I'm afraid
Hi all,
I cleaned all the connections last year when I fitted the exact start cables, along with the dielectric grease etc. I've rechecked them and they are all tight.
It's definitely a weekend job and my dad is here visiting for my born day next week and as he's an avid collector of old English bikes I am sure a bit of spannering to keep him away from annoying mother will be appreciated
I cleaned all the connections last year when I fitted the exact start cables, along with the dielectric grease etc. I've rechecked them and they are all tight.
It's definitely a weekend job and my dad is here visiting for my born day next week and as he's an avid collector of old English bikes I am sure a bit of spannering to keep him away from annoying mother will be appreciated
I'll give that a try and the TPS
Why the TPS?
To check whether the starter motor is receiving electricity attach a multimeter to the positive connection on it, ie the one from the solenoid and the other probe to an earth point. Thumb the starter and you should see 12v on the meter. If you do then the problem lies inside the starter motor, if not then the reason it’s not spinning over is because no leccy is getting to it.
If the problem is the start motor itself you need to drain the oil, pull off the RH crankcase cover so you can get to the starter motor attachment bolts. I think you also need to remove the stator and flywheel for the sprag clutch the starter engages with lies behind those items
Hola, so turn the ignition on, press the starter I get a click. I shorted the solenoid but nada. Not a thing. So I've tested the battery with the multi meter across the terminals 13.06v. With the ignition off I still get a voltage across the terminals of the solenoid of 11.68v. With the ignition on and pressing the starter, with the multi meter on the out terminal of the solenoid and on the starter motor terminal, nothing, 0v.
Looks like the leccy ain't getting through the solenoid?
K
Looks like the leccy ain't getting through the solenoid?
K
OK, just did the out terminal of the solenoid and onto an earth and 12.27v
And from the start motor terminal to earth, 12.27v. I think I've a dodgy earth somewhere
Just reading back through your post, I think it's the starter. I'll give it a whack with a mallet tomorrow to see if that helps. If not it's open heart surgery timeWhy the TPS?
To check whether the starter motor is receiving electricity attach a multimeter to the positive connection on it, ie the one from the solenoid and the other probe to an earth point. Thumb the starter and you should see 12v on the meter. If you do then the problem lies inside the starter motor, if not then the reason it’s not spinning over is because no leccy is getting to it.
If the problem is the start motor itself you need to drain the oil, pull off the RH crankcase cover so you can get to the starter motor attachment bolts. I think you also need to remove the stator and flywheel for the sprag clutch the starter engages with lies behind those items
Before opening up the crankcase cover you may be able to test the starter motor via its resistance. @AirCon or @Derek will be able to advise here better than me. If the starter motor coils are intact then there’ll be X ohms and if they’ve broken down, and thus the motor won’t spin within its magnets there’ll be Y ohms. Either of those 2 gents should be able to give you an approximation of X & Y values. There’s no point stripping the bike down and removing the starter if the issue lies with the solenoid.Just reading back through your post, I think it's the starter. I'll give it a whack with a mallet tomorrow to see if that helps. If not it's open heart surgery time
Cool, thank you. I will persevere with this bike as I love a challenge but its a joy to ride. I just want to be able to start it without worrying and having to call the breakdown each time.
I've my ST2 and 748, but would like to rack the miles up on this one this summer.
Again, thank you for all your help