idling on choke

[psyguy]

as thecafekid said, swap the cables/caps around just to make sure the spark is all good
and, i'm getting the impression you really need to take your carbs completely apart (again?) and meticulously clean them

[49er]

Hi, if you have not removed the pilot screws and the pilot jet (Under that rubber plug) and pushed carb cleaner through the passages and cleaned the pilot jet while out, your idling circuit may still be blocked.
It took me three try's initially before I found a small bit of loose gunk inside the pilot jet that was laying down and flipping up at times, I had to break it up with a copper wire and then it only came out when the carb cleaner was put to it.
On the CV's there you have an Air Pilot Jet with a biggish hole on the side of the airbox side. Then a Pilot Jet with a very small hole (see BassCliffs picture) quite deep in a tube under a rubber plug hanging down into the float bowl. The very thin brass tube is the fuel pickup to the choke or starter circuit. The idle circuit then has 3 very small holes close to the top lip of the butterfly on the engine side. One of these are adjustable with a Pilot Idling Screw that has a very small o-ring and washer and a spring around it and a very important and thin tapered tip. If someone has sprayed carb cleaner or some other rubber unfriendly substance on this tiny rubber o-ring it may have disintegrated already
The tapered tip of these Pilot Screws are known to become stuck and even break off, meaning that the adjustable hole for the idle mixture is then completely blocked. I personally have never encountered one so I am not sure if it is due to corrosion, such as water of a cleaning chemical getting past the threads or just ham fisted tightening. As a precaution I put a small amount of waterproof grease on the very fine threads of the pilot screw after cleaning and replacing the o-ring
You must remove those Pilot screws and make sure the idle feeding holes are open and that the Pilot screws are in good working condition and that an air fuel mixture can reach these holes via the Air Pilot jet and Pilot jet and that the Pilot screw can adjust this mixture.
You will have to check this on each carb and it cannot be done if the factory caps are in place, you will have to remove those.
There are some other ways of cleaning a carb in situ, but on a 4 -rack, rather remove, strip them down completely (this means that every rubber and other component and jet must be removed, clean each component meticulously, initially with clean fuel, then by spraying carb cleaner through all orifices not just into it, but it should shoot out the other side, as well as high pressure air. This is stage one. Now you can even boil the carb in clean boiling water with a bit of lemon juice for flavor (read that thread)!
Use this opportunity to check all the components for wear, diagrams rubber, needle slides, needle & seat.
Definitely replace all o-rings, especially if they are out of shape or brittle.
now reassemble carefully and make sure that your idle screw is backed out about 1 and a half to 2 turns. Give attention to the float height as well as this is a VERY important adjustment. Also if a PO has messed around with the carbs you may want to bench sync the throttle openings before hanging the rack.
Then finally if you really want to do yourself a favour replace al the japanese crosshead screws with metric allen stainless steel ones. the removel and stripping really becomes a breeze as you use T handle allen key wrenches.
I hope this motivates you enough to pull them apart completely. I was also daunted by this the first time. Print the guides that are available on the forum if you are wary of doing this, but believe me there is no shortcut, it sometimes is just luck if limited cleaning sorts a problem.

This is very informative, good advice, and you'll save yourself lots more agro by following it! Taking short cuts will not produce a sweet running engine.
You say that after further carb cleaning you've isolated the problem down to one cylinder. It this is so, you can rule out a faulty coil as this would affect 2 cylinders.
You need to remove all the pilot air and pilot fuel screws to ensure that those passages aren't partially/fully blocked. This is the most likey cause of your cold running cylinder. Use fine copper wire to check/clear any blockages, followed by more carb cleaner and compressed air.

In the list of things that you have already done, you say that "the breaker points are fine, just looked at them, no dirt or dust". Are your sure that your 850 is an '83. If so, it should be fitted with an electronic ignition!! If it has points, it will be a '79 and will be fitted with VM carbs not CV's as we were all assuming would be fitted to this model.
Do it right, do it once. Then enjoy the riding.:-D

[catbed]

i cleared all of the pilot passages, with wire carb cleaner, and compressed air, so they are clear im sure of it.

as for the "breaker points", it is electronic ignition. i just glanced at it the first time i looked and didnt notice. oops

[Matchless]

Just an afterthought. If the cylinder is firing (getting hot) on choke, then the electrical side should be OK and that points back to the carb. Make sure that you have a full float bowl, open the drain plug and check that it does not stop running out if petcock is on prime. A sticking needle valve may cause fuel starvation. If spark is OK and at the right time and choke gets fuel, then you are back to the idle circuit again.
Let us know how you are doing.

[catbed]

i got new intake boot orings and installed them. 2 cylinders still dont fire regularly. im going to do the valves soon but i dont think that will help much. correct me if im wrong.

i did the spark plug wire switch and it didnt affect the other 2 cylinders.

here are the spark plugs.

number 4


number 3

[catbed]

number 2 (no, this is not a new spark plug)


number 1 (a little rich)

[TheCafeKid]

i bet that valve adjustment will actually do wonders. give it a shot, you may be suprised. one and four definately need some help. Other two look pretty good.

[catbed]

on a scale of 1 to 10, how stupid do i feel?


100000000000000000000000000!


on my 4th time cleaning the carbs, i took out the main jet/needle jet and i noticed i had not cleaned a hole that was completely blocked by grime. guess that shows how carefully i cleaned them.

[psyguy]

on my 4th time cleaning the carbs, i took out the main jet/needle jet and i noticed i had not cleaned a hole that was completely blocked by grime. guess that shows how carefully i cleaned them.

well, now you know why people in the previous posts were going on and on about meticulously cleaning the carbs before attending to anything else

so, is it all sorted now? [-o<

[Matchless]

I think many of us came via that same road, I know I did. I also read all these posts and was sure that I had done what needed to be done, but the carbs were not working properly. On my 4th try I found the culprit and suddenly the light came on.
In retrospect it made me wonder about that VW beetle I had problems with many years ago and could never get to idle properly, the carb on opening and inspecting checked out good, but I had proven it by replacing with another carb that it WAS the carb, but I could not find the problem. Only now do I know that I needed to zoom in a bit more and actually test all orifices by squirting carb cleaner through them, and check for proper flow out. My partially blocked GS idle jet showed up when I did that and only then I saw the bit of dirt!
Let us know how your bike is running now!

[catbed]

that fixed it along with adjusting the mixture screws. she screams now and no hesitation on the throttle. post a vid in a few days. #2 cylinder fires now, just had to warm up longer. carb probably helped a bit.

[psyguy]

great news :-D

that fixed it along with adjusting the mixture screws. she screams now and no hesitation on the throttle. post a vid in a few days. #2 cylinder fires now, just had to warm up longer. carb probably helped a bit.

[catbed]

i still think theres something wrong with # 2 carburetor. i think a passage may be plugged still. heres the spark plug.

[Jd Powell]

May want to do a compression test on #2. That plug dosent look like its seen much combustion.

[Steve]

i still think theres something wrong with # 2 carburetor. i think a passage may be plugged still.

First of all, let's make sure we're numbering the cylinders correctly: #1 is on your clutch hand side, #4 is on your throttle hand side. 8-[

So, if that is, indeed, your #2 plug, a prime suspect is the vacuum diaphragm in the petcock.
If that leaks, it allows fuel down the vacuum line, which will enrichen the mixture for that one cylinder.


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