Cylinders 2 and 4 are dead cold!

[Guest]

this might be related to this post:

http://www.thegsresources.com/_forum/showthread.php?p=2076079#post2076079

My problem might escalate all the way to valve adjustment...(Exhaust valves maybe, I tried to be brief but just couldn't but Please Advise ! )

My story:

I got this 1983 GS 1100 GL has 8500 mi. (that's right less than 9k miles)
I cleaned the carbs, shinny freed jets, no leaks, floats leveled, new gaskets etc... all-in I'd say.
I tested the coils ( 3.2 and 3.4 Ohms)
this is not my first bike but I'm not an expert either... this looks like a bucket of gremlins I've been catching but I'm stucked with this one....

Bike starts right up, but running only on cylinders #1 and #3 ( 2 and 4 are dead cold )
I recall riding the bike with the old spark plugs and after a few laps around the block, all exhaust pipes were hot.

this happens no matter how I set the carbs ( 2 1/2 turns out, now 1 1/2 )
or even if I switch the coil cables.... 1to4 or 4to1, 2to3 or 3to2.
I just put new recommended NGK B8ES spark plugs, they all have spark, even the old ones had visible spark.

I'm very positive I can rule out carburation, All my floats have gas, all cv intake sucks enough to get my hand stucked on it and pull gas if I do so, all sliders are free and happy bouncing. Even if I had synched the carbs at high revs I'm guessing it wouldn't make any difference since I tried different configurations for the pilot air mixture screw. am I right? I know it's running lean now ( 1 1/2 turns out)

I'm also on the positive side I can rule out ignition timing since I got spark and no matter how I set the coils I cannot transfer the problem to the other cylinders. The symptom appears to be the same, I would say If only one coil was firing I would have cylinder 1 and 4 hot or cold ... in the same way 2 and 3 would be hot or cold but not mixed as I have it now... could I say is firing on time? Also, the bike will stumble and die if I remove any of the coil plugs from the spark plugs.

My conclusion and my fear is exhaust valves 2 and 4 are leaking? and somehow they work at high revs? as a low miles bike, I think they never serviced the valves, it's all stock all unmolested.
would anyone have another conclusion? thanks!

[Nessism]

Most likely the carbs. You might want to go though the carb rebuild tutorial linked in my signature to see if you missed any steps, and also check the Newbie Mistakes thread also linked, just in case anything applies.

Good luck

[RGM]

It is always one of three things, Ignition , compression or fuel/air. What is your compression at?

[posplayr]

this might be related to this post:

http://www.thegsresources.com/_forum/showthread.php?p=2076079#post2076079

My problem might escalate all the way to valve adjustment...(Exhaust valves maybe, I tried to be brief but just couldn't but Please Advise ! )

My story:

I got this 1983 GS 1100 GL has 8500 mi. (that's right less than 9k miles)
I cleaned the carbs, shinny freed jets, no leaks, floats leveled, new gaskets etc... all-in I'd say.
I tested the coils ( 3.2 and 3.4 Ohms)
this is not my first bike but I'm not an expert either... this looks like a bucket of gremlins I've been catching but I'm stucked with this one....

Bike starts right up, but running only on cylinders #1 and #3 ( 2 and 4 are dead cold )
I recall riding the bike with the old spark plugs and after a few laps around the block, all exhaust pipes were hot.

this happens no matter how I set the carbs ( 2 1/2 turns out, now 1 1/2 )
or even if I switch the coil cables.... 1to4 or 4to1, 2to3 or 3to2.
I just put new recommended NGK B8ES spark plugs, they all have spark, even the old ones had visible spark.

I'm very positive I can rule out carburation, All my floats have gas, all cv intake sucks enough to get my hand stucked on it and pull gas if I do so, all sliders are free and happy bouncing. Even if I had synched the carbs at high revs I'm guessing it wouldn't make any difference since I tried different configurations for the pilot air mixture screw. am I right? I know it's running lean now ( 1 1/2 turns out)

I'm also on the positive side I can rule out ignition timing since I got spark and no matter how I set the coils I cannot transfer the problem to the other cylinders. The symptom appears to be the same, I would say If only one coil was firing I would have cylinder 1 and 4 hot or cold ... in the same way 2 and 3 would be hot or cold but not mixed as I have it now... could I say is firing on time? Also, the bike will stumble and die if I remove any of the coil plugs from the spark plugs.

My conclusion and my fear is exhaust valves 2 and 4 are leaking? and somehow they work at high revs? as a low miles bike, I think they never serviced the valves, it's all stock all unmolested.
would anyone have another conclusion? thanks!

So do a compression test?

[BigD_83]

Can you confirm...

have you adjusted the valves?

[RiceCooker]

I haven't adjusted the valves also I don't have a number of PSI on each cylinder. I'm guessing, simply my thumb being blown away from the spark plug hole could not be accurate enough this time
I've never had this kind of problem in other bikes so I'll borrow a tool, let you guys know.

thanks again everyone.

[posplayr]

I haven't adjusted the valves also I don't have a number of PSI on each cylinder. I'm guessing, simply my thumb being blown away from the spark plug hole could not be accurate enough this time
I've never had this kind of problem in other bikes so I'll borrow a tool, let you guys know.

thanks again everyone.

If it is blowing your finger away, it is likely enough pressure to fire.

[greg78gs750]

valve adjust is not an escalation, it is the baseline.

[Brendan W]

Is it possible you have the HT leads connected the wrong way? Isn't this model an odds and evens i.e. 1/3 & 2/4 instead of 1/4 & 2/3 ?

[hjfisk]

Is it possible you have the HT leads connected the wrong way? Isn't this model an odds and evens i.e. 1/3 & 2/4 instead of 1/4 & 2/3 ?

NO it is not they fire , 1-4, and 2-3,

[barnbiketom]

I'm very positive I can rule out carburation, All my floats have gas, all cv intake sucks enough to get my hand stucked on it and pull gas if I do so, all sliders are free and happy bouncing. Even if I had synched the carbs at high revs I'm guessing it wouldn't make any difference since I tried different configurations for the pilot air mixture screw. am I right? I know it's running lean now ( 1 1/2 turns out)

What makes you think all the INTERNAL passageways aren't clogged??? pilot jet? air bleeds? etc etc?? I bet carbs are at fault....
It will probably only take FIVE SECONDS to confirm.
Spray a small shot of ether or even wd-40 into the airbox or sync ports when bike is idling. if 2 and 4 pick up.. you have plugged carbs. easy

[OldVet66]

RiceCooker, you are all over the place chasing your tail. Adjust your valves, do a compression test, rebuild your carburetors properly (If you haven't torn them down completely and soaked them for 24hrs. in carburetor dip, you have been wasting your time even touching them) Nessism gave you the best advice in the beginning and you ignored it. The answers are there in those steps.

[RiceCooker]

Ok, tonite I'll do this...
- check compression (with a proper tool )
- spray carb cleaner on 2 and 4 and see if idle speeds up

What makes you think all the INTERNAL passageways aren't clogged??? pilot jet? air bleeds? etc etc?? I bet carbs are at fault....

You are right, I soaked them, sprayed them with carb cleaner and blew air through the passages... that doesnt mean they didn't get clogged again by other means

valve adjust is not an escalation, it is the baseline.

I agree that is the baseline but I meat escalation from simple/cheap/fast to complicated/expensive/time consuming. If I can avoid a valve job by cleaning the carbs that's a good day
there's always the risk of screwing the gasket up and had to get a new one.

[BigD_83]

You seem to be under the impression that checking and adjusting your valves is an expensive, time-sucking job. Nothing could be further from the truth.

Just get'er done, as they say. Even if a complete strip and dip cleans up the carbs for you, the valves still need to be checked and adjusted. The good news is, that can be done while you have the carbs apart.

[greg78gs750]

there is no avoiding valve adjustment. and it is much easier than a proper carb cleaning. but hey, maybe i am wrong here.