High compression and non-firing cylinder

[rockford]

Clean

Wish I had a dollar for every time someone says their carbs are "clean", only to learn they weren't.

Fuel or spark. You tell us.

You may be meticulous but I wouldn't swap my carb rebuilding experience for yours. I think that's a mean comment but not unlike some other flippant comments that I remember seeing from you. You must be quite a guy! Do you do a better job than anyone else? Are you the only one capable of cleaning carbs the way they should be cleaned? How do you know? Being a self-confident know-it-all is no reason to be rude.

I wish I had a dollar for every time someone made an mean, uncalled for, foolish, self-gratifying comment.

As far as your "fuel or spark" question, if you weren't so quick to kick out a smug response, you might know what was stated.

[Nessism]

You may be meticulous but I wouldn't swap my carb rebuilding experience for yours. I think that's a mean comment but not unlike some other flippant comments that I remember seeing from you. You must be quite a guy! Do you do a better job than anyone else? Are you the only one capable of cleaning carbs the way they should be cleaned? How do you know? Being a self-confident know-it-all is no reason to be rude.

I wish I had a dollar for every time someone made an mean, uncalled for, foolish, self-gratifying comment.

As far as your "fuel or spark" question, if you weren't so quick to kick out a smug response, you might know what was stated.

Dude, it's simple...Fuel or Spark. You have shot down every suggestion made saying all the bases are covered. Well, something is obviously wrong and and you have not stated how you verified the pilot jets are open. Did you stick a wire though them? Hold them up to a light to make sure you can see a hole though the center? Also, regarding the carbs did you replace all the various O-rings? The old o-rings turn hard and brittle with age so did you get a kit from Cycleorings.com to make sure all the various parts are properly sealed? Where are the mixture screws set? Did you sync the carbs? All these details matter yet you have not provided any information.

About 7500 of my posts here have been in the Tech forum helping the newbies that come to the GSR, and I'm serious about all the people that say their carbs are "rebuilt" when they are not. I don't know you from Adam, and sorry to offend, it's just that we have seen this thing go on hundreds of times before from people that shoot down suggestions without providing reasonable evidence as to what they have done to their bikes.

Yea, I'm coarse. Guilty and non remorseful.

Oh, and 170 psi is not high compression on a GS engine. It's within the normal spec range for your bike that's in the factory service manual.

[tkent02]

You've obviously never switched out a set of carbs on a motorcycle.

Three sets this week.
Fix your own fvcking bike.

[rockford]

Poor you!!

There's no reason to stick a wire through something I can see through. If it were clogged, I'd be most willing to point that out. All of my "O" rings are new and I've cleaned my carbs as best I know how. So much for bikes, you fellas have bigger problems.

OK, so one of you can "swap out" a rack of carbs in 10 minutes? Who, in his right mind would believe that?

Now, the other one's importance in life is based upon 7500 posts which often simply parrot answers already provided? At the same time, you know how good of a job others do cleaning their carbs? Is this your life's work? God, I hope not.

I'm not in the 'clique' and I don't miss it a bit! Your foul self-important attitudes have led to this forum losing so many people who once had a lot of enthusiasm. You don't have any interest in GS motorcycles; you only have interest in your selfish desire to be appreciated.

[first timer]

when you rebuilt your carbs did you dip them or spray them?

slides moving freely? no pin holes in the diaphrams?

are the plugs new? sometime plugs just go bad and will drive people nuts with bad running bikes carbs will be spotless but still run like crap until new plugs are in.

None of your fuel mix needle tips are broken off in the little hole are they?
Did you stick a fine wire in every hole you could find? Includeing the 3 little holes in the carb body by the butterfly valve?

you swap your #1 and #4 plug wire?

I know you may feel like you are running in circles right now but we have to start some where when promblem solving. and each thing you can check off helps us think of other things it could be.

Like said your engine only needs air, gas and spark, and one of those three is out of wack so it's just a matter of eliminating things.

[fenderfreek]

There's no reason to stick a wire through something I can see through. If it were clogged, I'd be most willing to point that out.

You didn't, however, point out that you could see through there. That's all anyone has asked for - what you did to make your conclusions and verify these things. It takes it from guessing and postulating to mere logical deduction.

All of my "O" rings are new and I've cleaned my carbs as best I know how. So much for bikes, you fellas have bigger problems.

Again, this is the first time you've pointed this out. You'd be surprised how many people's definition of "clean" carbs means taking them off and blasting a little aerosol carb cleaner in there.

OK, so one of you can "swap out" a rack of carbs in 10 minutes? Who, in his right mind would believe that?

I'm hardly adept this, but it doesn't take more than 20-30 minutes for me. I would consider it an hour well spent if it solved the problem. If not, you at least know what's *not* wrong with it. It wouldn't surprise me if a seasoned bike mechanic could do it in half the time as me.

Now, the other one's importance in life is based upon 7500 posts which often simply parrot answers already provided? At the same time, you know how good of a job others do cleaning their carbs? Is this your life's work? God, I hope not.

No, but covering your bases is always a good thing. Better to over-scrutinize a problem than possibly miss or ignore critical details. It's called being "thorough".

I'm not in the 'clique' and I don't miss it a bit! Your foul self-important attitudes have led to this forum losing so many people who once had a lot of enthusiasm. You don't have any interest in GS motorcycles; you only have interest in your selfish desire to be appreciated.

Gaining members every day because people come here and get their bikes fixed by this "clique". If you can't appreciate someone being thorough in their assessment of your situation(without seeing the bike and what you did, no less), then you should probably grab the phonebook and find a bike mechanic. If taking a time-proven critical approach to someone's methods is being "self-important" to you, then I wouldn't go around asking for advice, because you'll meet a lot of "self-important" people.

[rockford]

Frustration

My frustration arose because of the fact that I did a perfect job cleaning the carbs, including everything that was mentioned. They were dipped and soaked at length. I've got a little tool that pushes through the jet holes. This time, I put in 2 new OEM pilot jets, including #4. I replaced the "O" rings (I always do) but even if I hadn't, the only one that could cause this sort of problem would be the #4 needle jet ""O" ring (unless all the gas leaked out of the others getting there).

If anyone can exchange the carbs on a stock GS750L in 10 minutes, put it on Utube. I'd love to see it and I'm sure many others would, as well. I think I work a little slower than many of you but I also think it would be a truly amazing feat.

I'll try to be more tolerant in the future and when I get this figured out, I'll report back (even if there's a problem with the carb).

[Dave8338]

You didn't, however, point out that you could see through there. That's all anyone has asked for - what you did to make your conclusions and verify these things. It takes it from guessing and postulating to mere logical deduction.



Again, this is the first time you've pointed this out. You'd be surprised how many people's definition of "clean" carbs means taking them off and blasting a little aerosol carb cleaner in there.



I'm hardly adept this, but it doesn't take more than 20-30 minutes for me. I would consider it an hour well spent if it solved the problem. If not, you at least know what's *not* wrong with it. It wouldn't surprise me if a seasoned bike mechanic could do it in half the time as me.



No, but covering your bases is always a good thing. Better to over-scrutinize a problem than possibly miss or ignore critical details. It's called being "thorough".



Gaining members every day because people come here and get their bikes fixed by this "clique". If you can't appreciate someone being thorough in their assessment of your situation(without seeing the bike and what you did, no less), then you should probably grab the phonebook and find a bike mechanic. If taking a time-proven critical approach to someone's methods is being "self-important" to you, then I wouldn't go around asking for advice, because you'll meet a lot of "self-important" people.

Now THAT...was VERY well written. Nice job!

Rockford, the carb issue is one of the most frequently asked questions here in the tech section. As a matter of fact, my first question was about the CV carbs as I had never worked on a set before. Hollys, Carters, Rochesters, tillotsons, Keihins and any number of 2-stroke set ups, too many times to remember but nothing specific to the Mik CV setup.

These bikes are notorious for running lean, as a matter of a finely tuned carb and EPA import regs in the 80's...that's just how they are. When you introduce even the slightest restriction in fuel flow or just slightly more air as a result of cracked o-rings, The bike will let you know.

Something as simple as an over-oiled air filter will cause a GS to run rich.
A leak/ crack in an intake o-ring or rubber mount will cause a lean condition most noticeable at an idle (usually higher than the base of 1100 RPM's) An airbox not sealed tightly will cause a lean condition through out the RPM range.

All of this may be known to you. Some may not. Those that have replied to your post are among the best on the fourm as it relates to carb issues. It's not that anyone is trying to belittle you or your abilities, but we are trying to aid in solving the problem that your bike is having. I think I can safely speak for all here in that we LOVE the GS bikes to life...not death.

Any and all questions are welcome. Mods (4-1 pipe or pods) make the fine tuning just that much more critical.

Now lets get that bike up and on all four.

[rockford]

Thanks

Thanks! #4 isn't running lean; it's not running at all, I don't think. I set my air screws when I synched it and the plugs still look perfect. I'm convinced that the problem is elsewhere based on a whole bunch of reasons including the fact that the problem existed both before and after the last carb rebuild.

My best suspicion right now is that it may be a valve. They shouldn't need adjusting based on how long and how many miles it's been since I did it last but, who knows? Maybe something went wrong.

[Nessism]

If the compression is 170 psi in that cylinder the problem is not the valves.

[Dave8338]

Have you pulled the fuel drain plug on the bottom of the #4 carb?

Can you get the bike to run on all four when you mist the air box with fuel?
(I like to use my two stroke mix --little better for things when they're running dry)

Your valves won't be the problem if your compression #'s are that good. It sure sounds fuel (the lack of it) related to me... If you had valves that were too tight or rings that were stuck, the compression #'s would be much lower.

[rockford]

Thank you

If the compression is 170 psi in that cylinder the problem is not the valves.

Thank you. I'm glad to learn that.

[rockford]

Fuel

Have you pulled the fuel drain plug on the bottom of the #4 carb?

Can you get the bike to run on all four when you mist the air box with fuel?
(I like to use my two stroke mix --little better for things when they're running dry)

Your valves won't be the problem if your compression #'s are that good. It sure sounds fuel (the lack of it) related to me... If you had valves that were too tight or rings that were stuck, the compression #'s would be much lower.

Yeah, I've pulled the float bowl and there's plenty of fuel getting to it. (I compared it with #1.) I agree that it sounds like a fuel problem. I haven't tried the fuel mist deal but it sounds like a good idea. I'm assuming my idle would increase a little if the cylinder is currently starved.

I guess if the idle goes up, that would mean a carb problem and I'd have to go out and find a crow to eat!

[hampshirehog]

You can always squirt a teaspoon of petrol into the motor via the plug hole. If that cylinder fires you'll know for sure it's carbs (which it really sounds like it is).

Either that or pop in a Colortune - you'll see if you're getting a spark under compression.

[Steve]

I just read through this for the first time and am a bit surprised at the attitudes that are starting to show.

I am also a bit confused by some of the statements that Rockford is making:

My frustration arose because of the fact that I did a perfect job cleaning the carbs, including everything that was mentioned. They were dipped and soaked at length. I've got a little tool that pushes through the jet holes. This time, I put in 2 new OEM pilot jets, including #4. I replaced the "O" rings (I always do) but even if I hadn't, the only one that could cause this sort of problem would be the #4 needle jet ""O" ring (unless all the gas leaked out of the others getting there).

If anyone can exchange the carbs on a stock GS750L in 10 minutes, put it on Utube. I'd love to see it and I'm sure many others would, as well. I think I work a little slower than many of you but I also think it would be a truly amazing feat.

I'll try to be more tolerant in the future and when I get this figured out, I'll report back (even if there's a problem with the carb).

Unless something has been changed, your '81 bike should have CV carbs. The needle jets do not have o-rings.

Haven't tried it on a 750L but I have done the carbs on my wife's 850L in about 15 minutes. I have no intention of putting it on YouTube.

There's no reason to stick a wire through something I can see through. If it were clogged, I'd be most willing to point that out. All of my "O" rings are new and I've cleaned my carbs as best I know how. So much for bikes, you fellas have bigger problems.

OK, so one of you can "swap out" a rack of carbs in 10 minutes? Who, in his right mind would believe that?

Now, the other one's importance in life is based upon 7500 posts which often simply parrot answers already provided? At the same time, you know how good of a job others do cleaning their carbs? Is this your life's work? God, I hope not.

I'm not in the 'clique' and I don't miss it a bit! Your foul self-important attitudes have led to this forum losing so many people who once had a lot of enthusiasm. You don't have any interest in GS motorcycles; you only have interest in your selfish desire to be appreciated.

Actually, there is a reason to stick a wire through there. I have found that if there is any moisture at all in a jet hole and you look at a light through the hole, it appears bigger than it acually is. I prefer to use a strand of copper wire as it is less likely to scratch the brass jet. This will ensure that there is no crud in the jet, slightly reducing its diameter and its ability to meter fuel flow.

Nice to know you have cleaned the carbs "as best I know how". Our problem is that we hear this pretty much every day from a lot of new people that are trying to resurrect an old bike. They have no idea what they are doing, and think that merely removing the float bowls and spritzing some spray in there constitutes "cleaning the carbs". We have no idea if you fall in that category. So far, you have only mentioned cleaning the carbs, but never mentioned how, so we don't know if they were properly dipped and re-o-ringed.

Yes, many of us do have bigger problems, but we tend not to bring them to this board as they don't have anything to do with GS motorcycles. And, evidently, we are not the only ones with bigger problems.

There is a "clique" here? I must not be in it, either. I have never been invited, in fact, I have never heard of one.

Thanks! #4 isn't running lean; it's not running at all, I don't think. I set my air screws when I synched it and the plugs still look perfect. I'm convinced that the problem is elsewhere based on a whole bunch of reasons including the fact that the problem existed both before and after the last carb rebuild.

My best suspicion right now is that it may be a valve. They shouldn't need adjusting based on how long and how many miles it's been since I did it last but, who knows? Maybe something went wrong.

The problem may have existed before the last carb rebuild, but it might be caused by something that is plugging a passage in the carbs. If, by chance, the carbs were not thoroughly cleaned to remove that blockage, the problem would still exist. I'm not saying that your carbs are dirty, but merely pointing out that although you are convinced the problem lies somewhere else, it might still be in the carbs.

I don't think the problem is with the valves, either, but I am just curious ... how long and how many miles since they were adjusted?

.