Is this a carb problem ?

[mally]

Need help Guys this bike really getting to me.
2000 St1100 ABS/TCS
The Problem ??
Idling the Engine at 1100 revs it pops and sounds like running on 3 Cylinders. Taking revs up to 2500 revs sound worse.
With Engine running take 1 and 3 HT leads off leaving 2 and 4 HT leads on, Engine runs no change in sound.
Take 2 and 4 HT leads off leaving 1 and 3 on while Engine running the Engine dies.
Starts fine with just 2 and 4 HT Leads connected and 1 and 3 disconnected.
Doesn’t start properly with just 1 and 3 connected and 1 and 4 disconnected but if you rev the engine it runs but dies when you drop the revs.
Seems just the right hand side has a problem.

List of things done
New spark plugs x4
Replaced Coils.
Replaced CDI unit.
Replaced Carburetor to engine rubbersx4.
Carburetor cleaned.
On replacing everything all electric leads was checked with Ohms (Ω)meter
-Coils HT leads 24.4 Ω (22.5-27.5Ω).
- Coil wires 3.00Ω (2.16-3.19Ω).
-Pulse 435Ω (405-495).
Pulse not removed but was checked with Ohms meter and seemed fine.
Fuel pipe to Carburetor checked and cleaned, pump working and pet cock in working order.

Any ideas welcome thank you.
Mal

 

[Slydynbye]

Spark plugs?

 

[mally]

renewed spark plugs .

 

[Slydynbye]

Does that mean new or refurbished?
Have you seen the spark across the electrode

Pull the plugs and post pics?

 

[ChriSTian_64]

I would visually make sure plug 1 and 3 are making... sparks, meaning they are electricaly fed properly.
Also... that the good wires are going to the good plug ( so that they spark at the right time). But they have different lenght, so they are hardly reversed. Just a double check.

 

[mally]

thanks for all the ideas guys keep them coming all try them all asap weather not to good in liverpool england.

 

[Bikeric]

Try disconnecting your fuel tap and starting the bike again, I had this problem and removing the fuel tap cured it. Still off now with no ill effects. Look in Articles (top of the page), ST1100 Articles, Emergency bypass of the fuel valve.

 

[ChriSTian_64]

1 and 3 are on the same side : right hand when sittting on bike.
And yeah, it seems that there is something wrong on this side.
I would say, re-check the wires you have disconnected.

 

[ChriSTian_64]

thanks for all the ideas guys keep them coming all try them all asap weather not to good in liverpool england.

What do you mean : A.S.A.P. ?
There is no reason to hurry : weather is always bad in England.
hi hi hi
You'll have plenty of time. ;-)

 

[mally]

in work tomoz off sunday but on baby duty lol so looks like monday

 

[ST11Nut]

I'm wondering if you have the carbs seated fully into the boots on the left side (1&3)

 

[ChriSTian_64]

If you have invert the cables going to the spark plug, on the right side, 1 and 3 are not firing when is the good time, so these cylinders are not firing.
But I told you this already, right ?
Right !
The cylinders firing order is 1-4-3-2.
1 and 3 are 2 cycles apart.
That means that if you revert the spark plug cables, instead of firing at the end of cycle 2 (when the mixture is compressed and ready to explode) instead, it will spark at the end of cycle 4, after the air-gas mixture had evacuated the cylinder thru the exaust.
My spark plug cables are numbered, to be sure they are connected on the good spark plug. And also, they have different lenght, so you can hardly mix them.

But, this only work, if they are connected at the good connector at the other end.

 

[bdalameda]

Where did you get your spark plugs? There are some Chinese made counterfeit knockoff NGK plugs out there being sold all over. They have been causing a lot of grief with some people.

 

[ST1100Y]

Would need more hiSTory on the bike...
Besides air-leaks can clogged/obstructed idle jets also cause some "misfiring sounds" <4000rpm...

 

[Roger]

Has it been running OK? What have you done/changed since then?
The ign. system has a redundant spark so only needs two ign. coils - have you got spark on the 'bad' side?
If good sparks, but still two bad cylinders - have the carbs. lost synch somehow? Has the choke mechanism jammed on? Is there a bad intake leak?
Questions, questions.....

 

[mally]

been rechecking wires etc and have now found that the ohms on the pulse is below the spec . the spec I have is between 405-495 ohms but mine is show 394 ohms would this explain why 1 and 3 cylds are not working properly ?