Fuel starvation?

Joined
Apr 22, 2017
Messages
48
Location
Gt Manchester UK
Bike
ST1100
On a 1000+mile trip to Scotland in November the bike was running fine during nearly all of the trip. On the way back I refuelled at motorway services then proceeded at slightly illegal speeds down the M74 motorway. After about 4 miles the bike lost power- it felt like it was running on 2-3 cylinders gradually losing speed on a constant throttle. I pulled onto the hard shoulder where the engine started running fine again. After another 10 miles or so at the same speeds the same thing happened again and once again rectified itself once I pulled in and let it idle for a minute or two. I carried on the journey at around 50-60 mph and when near home increased speed to previous slightly illegal speeds (ok, 90ish+ mph).
Anyway the problem didn't reoccur. Road conditions were good with no rain. Since then the bike has been in my garage for general strip down and swing arm repaint.
I've given it a full service - plugs, air filter(s) etc changed the fuel filter and checked electrical connections. The tank is clean as a whistle inside and I have checked the breather pipes and blown out with air. As it's all going back together now I'd be really grateful of any suggestions to the possible cause and anything I've missed and should check whilst all the plastic is off. Thank you and Happy Christmas/ Seasonal greetings to all.
 
Joined
Oct 9, 2012
Messages
81
Location
Singapore
Bike
ST1100Y
This sounds like a fuel pet cock issue, you can try to bypass the petcock and see if the issue goes away. I had similar problems many moons ago, discovered my petcock diaphragm had a tear, when at speeds, bike would starve & seems to be running on 2-3cyclinders, lower speeds issue goes away.

In any case, most folks here bypass/toss the fuel petcock, I rebuilt mine with a kit available.
 
OP
OP
Big-E
Joined
Apr 22, 2017
Messages
48
Location
Gt Manchester UK
Bike
ST1100
This sounds like a fuel pet cock issue, you can try to bypass the petcock and see if the issue goes away. I had similar problems many moons ago, discovered my petcock diaphragm had a tear, when at speeds, bike would starve & seems to be running on 2-3cyclinders, lower speeds issue goes away.

In any case, most folks here bypass/toss the fuel petcock, I rebuilt mine with a kit available.
Thanks for that. I'll check it out. Repair kits via ebay mainly from USA but postage not much.
 
Joined
Oct 9, 2012
Messages
81
Location
Singapore
Bike
ST1100Y
You can bypass the petcock and confirm if the issue is fixed/root cause, and then decide later on if you’d like to permanently bypass or rebuilt it.

where I’m located, Honda do not sell the kit individually, only option is to replace the petcock.
i got my K&L kit from USA as well.
 
Joined
Feb 25, 2016
Messages
4,759
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Northumberland UK
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VStrom 650
Big E, it's probably the November Scottish air it has that effect on body, soul and machinery.
But I agree with the above, petcock advice.
Upt'North.
 
OP
OP
Big-E
Joined
Apr 22, 2017
Messages
48
Location
Gt Manchester UK
Bike
ST1100
Big E, it's probably the November Scottish air it has that effect on body, soul and machinery.
But I agree with the above, petcock advice.
Upt'North.
Nah, well 'ard here. Bin doin' the trip for 20 years now to Applecross same time each year, rain, shine, hail and snow. Might be getting a bit old for it now...........:) Petcock seems route to follow, thanks. Seasons greetings! (I've been banned from the garage tomorrow)
 
OP
OP
Big-E
Joined
Apr 22, 2017
Messages
48
Location
Gt Manchester UK
Bike
ST1100
You can bypass the petcock and confirm if the issue is fixed/root cause, and then decide later on if you’d like to permanently bypass or rebuilt it.

where I’m located, Honda do not sell the kit individually, only option is to replace the petcock.
i got my K&L kit from USA as well.
Same over here. K&L kit seems way to go. Cheers.
 

lomita

In God We Trust
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Sep 1, 2013
Messages
427
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SOCAL
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2009 ST1300 ABS
Nah, well 'ard here. Bin doin' the trip for 20 years now to Applecross same time each year, rain, shine, hail and snow. Might be getting a bit old for it now...........:) Petcock seems route to follow, thanks. Seasons greetings! (I've been banned from the garage tomorrow)
Answer me this, how is driving on snow? I'd like to 'ardin up my cold weather driving skills.
 

kiltman

Site Supporter
Joined
Apr 27, 2013
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68
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Stratford, Ontario Canada
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2002,ST1100ABS
STOC #
8826
When you refuel and release the fuel cap, is there a whoosh sound of air escaping? If not there's a remote possibility that the fuel cap is faulty and may need to be replaced. I'm just throwing this out there as this was an issue with mine under similar circumstances as you describe.
 

Ron

Joined
Feb 5, 2005
Messages
1,665
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Orlando
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ST1100s
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2432
Don't forget to plug the Vac. line. I used one of the screws that hold the bracket to the filter housing.
 
Last edited:
OP
OP
Big-E
Joined
Apr 22, 2017
Messages
48
Location
Gt Manchester UK
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ST1100
Don't forget to plug the Vac. line. IU used one of the screws that hold the bracket to the filter housing.
Thanks Ron. Been pondering on this one, what is the actual point of having shut off valve given that fuel isn't going anywhere if pump switched off?
 

bdalameda

PaleoCyclist
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Jan 13, 2009
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67
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Salinas, California
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Africa Twin
Thanks Ron. Been pondering on this one, what is the actual point of having shut off valve given that fuel isn't going anywhere if pump switched off?
To prevent fuel leaking through into the carbs if the bike is laying over and flowing out the carb overflow lines. It is a required safety by most countries to have a positive fuel shutoff in case of an accident to keep fuel spills contained.
 
OP
OP
Big-E
Joined
Apr 22, 2017
Messages
48
Location
Gt Manchester UK
Bike
ST1100
To prevent fuel leaking through into the carbs if the bike is laying over and flowing out the carb overflow lines. It is a required safety by most countries to have a positive fuel shutoff in case of an accident to keep fuel spills contained.
Good point and noted. Thanks.
 
Joined
Aug 6, 2011
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241
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Grand Haven MI
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2004 ST1300
STOC #
8800
I made a small steel blank plate to replace the diaphragm. Use the housing as an pattern.
Just wanted to keep the bike looking stock.
 

Whooshka

Fairly faST old guy
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Jan 29, 2017
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1,009
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New Jersey
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2006 ST1300
Sometimes people over think things. You fueled up, it happened a few times then went away. My guess is you got a bad tank of gas. Maybe a piece of dirt or whatever temporarily clogged a line.
 
OP
OP
Big-E
Joined
Apr 22, 2017
Messages
48
Location
Gt Manchester UK
Bike
ST1100
Sometimes people over think things. You fueled up, it happened a few times then went away. My guess is you got a bad tank of gas. Maybe a piece of dirt or whatever temporarily clogged a line.
Yep, that was my first thought when it happened. It may well be the reason and indeed may not reoccur. At the moment just looking to cover all basics whilst bodywork off. Thanks for the reply.
 
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