Author Topic: Chasing rough running problem  (Read 3587 times)

Offline Bikebear

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Chasing rough running problem
« on: August 28, 2012, 08:02:12 PM »
Went for a great ride on Sunday everything was working sweet, I even passed a Hayabusa and an R1 on the Gillies. We stopped for lunch at the top pub in Ravenshoe and that's where the rot started. I left the pub and the bike started to run rough, all gears all speeds. No popping or backfiring on downhill runs just a vibration. 
Someone suggested that I may have got some dirty fuel but I couldn't understand why it only started to happen halfway through the ride. I put some fuel system cleaner in and went for a blast, still not much difference so I decide to investigate.
Pulled the bike down, don't you love plastic, and started checking stuff. The fuel filter was looking pretty dirty so off to Honda for a new one, only $7.50 for an Emgo brand identical to the Honda unit, called in at Bursons for a new set of plugs and back home to get stuck in. So I put the new filter in, no difference still running like crap, new plugs.. ditto, so time to check vacuum hoses.. all seem ok. Out with the Carbtune.. hmmmm.. carbies don't seem to want to balance.. could it be the dreaded split manifold rubbers? Pulled more plastic and crap off to access the base of the carbies.. ok one of the rubbers feels a little loose, time to bite the bullet. Out with the laptop and look up the service manual section on carby removal.. hmmm dunno why people are so afraid this looks simple enough, undo the clamps, disconnect the enrichment cable, the carby drain lines, fuel line and pull the assembly out. No need to disconnect the throttle cables as there is plenty of room to swing the assembly to the side. Pulled the rubbers off and there is no sign of splits or damage but the one that appeared loose was actually a little loose so maybe it was sucking air. So after checking everything time to put it back together, hmm.. not that easy trying to line the rubbers and manifolds up but with a little gentle persuasion and leverage they finally lined up. Aircleaner back on, oh look at that the sub aircleaner is supposed to have a piece of foam in it, it's never had one as long as I've had the bike.. grabbed a P1 dust mask and cut a filter out of that until I can get an appropriate piece of foam. Time to fire up.. still running rough.. out with the Carbtune and balance time.. aha.. this time they balance, still a little rough but much better. Tomorrow the plastic goes back on and out for a run up the coast to see how it goes with brand new fuel and balanced carbs. Fingers crossed.
Craig..
STOC #8215
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SCA#2478

Gold '99 ST1100A (Golden Brown), Black '04 VT750, Red '15 1800 Valkyrie (Hildr), Black '08 DN01



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Offline Biggles

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Re: Chasing rough running problem
« Reply #1 on: August 28, 2012, 08:47:17 PM »
Hope that fixed it Bear.  You're a legend to do that heart bypass surgery without any anaesthetic. 
Sometimes just pulling things apart and putting them back together fixes the problem.
Would the next job be to check the carby jets?  Dunno- just trying to think of what could cause something like that suddenly.
The vibration on coasting sounds a bit like a mechanical bug.
For the modern man who lives in the city, riding a bike might be one of the only ways to escape the humdrum monotony. To take off and ride. To be both at one with nature and one with the bike. To feel masculine. Adam Piggott

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Offline saaz

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Re: Chasing rough running problem
« Reply #2 on: August 28, 2012, 08:56:07 PM »
Let us know how you go. You have done the obvious stuff. Sounds a lot like when I had a dose of bad fuel.  It might take a while to get rid of it.

Also, don't discount that it may be running on less than 4 cylinders. A mates ST11 decided not to run on a cylinder and behaved the same. All it was was the spaark plug boot not connecting properly to the spark plug lead. A simple trim of the lead and refitting the boot fixed that issue.

Good luck!
« Last Edit: August 28, 2012, 09:01:22 PM by saaz »
John
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1996 Honda ST1100P
2014 Triumph Trophy SE
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Offline Tipsy

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Re: Chasing rough running problem
« Reply #3 on: August 28, 2012, 10:23:12 PM »
 :wht11 py

and maybe a little metho in the tank just in-case there is a bit of water present.
It cant hurt any way.

Tipsy
« Last Edit: August 29, 2012, 08:40:41 AM by Tipsy »
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terrydj

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Re: Chasing rough running problem
« Reply #4 on: August 29, 2012, 07:58:41 AM »
:wht11 py
and maybe a little metho in the tank just in-case there is a bit of water present.
It cant any way.
Tipsy

+1 on the Metho in the tank. Most excellent for getting rid of the water
 

Offline Bikebear

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Re: Chasing rough running problem
« Reply #5 on: August 29, 2012, 01:04:30 PM »
Went for a quick ride today, seems better, the throttle response is certainly much sharper. I think crap fuel is most likely the culprit so I bought some fuel cleaner/conditioner and added that to a tank of fresh fuel so we'll see how it goes. I did put a dash of metho in the tank just in case it had water in it. I know it is running on all 4 because the plugs look ok, no sooty or wet ones.

Guess I'll just ride it and see if it gets better. I'm off to the Southern Cross Poker Run on Saturday so a hard run South should clean it out.

Thanks for the tips and suggestions.
Craig..
STOC #8215
UC #42145
SCA#2478

Gold '99 ST1100A (Golden Brown), Black '04 VT750, Red '15 1800 Valkyrie (Hildr), Black '08 DN01



"Golden Brown finer temptress, Never a frown with Golden Brown"
 

Offline saaz

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Re: Chasing rough running problem
« Reply #6 on: August 29, 2012, 01:23:14 PM »
After my experience with water in the fuel (or some other contamination) changing the fuel filter again after it is running ok might be advisable. The fuel cleaner gets the problem out of the tank but it may block the fuel filter some time in the future - in my case a few months later.
John
(Ridden on and forever in our hearts)
1996 Honda ST1100P
2014 Triumph Trophy SE
Ozstoc, STOC #7239, Farrider #461 Ulysses #061681, IBA #59143 and some others