No 1 Cylinder not getting warm

[zaipai]

Hi all,
I was enjoying my GS when last night I noticed that the No. 1 cyl was not firing, it was cold while the others very hot. I checked and there is spark and while the motor was running with the plug out it seemed as tho there was gas.. So question is what would keep it from firing?

Its a 1981 GS1000G largely stock, has about 34,000 miles on it.

Thanks,
Scott.

 

[49er]

You may have a bad connection or HT lead on #1 plug. Try swapping leads at the coil between #1 & 4 and see if the symptoms move to #4 pot. If so, you've isolated the problem and just repair/replace that lead.

 

[tom203]

If it has spark ( try switching 1 and 4 as stated), then check for fuel in bowl. Is the plug wet ? Do you use the kickstand mostly?

 

[Guest]

It takes several things for a cylinder to fire up. Spark, compression, and gas. Spark does have to have the right timing though. As already suggested swap plug wires 1 & 4, they're on the same ignition timing circuit. If you still have the same problem, swap the plugs also. Still no fire, see if that plug is dry and if it is your not getting gas to that cylinder. Hopefully it'll just be the plug.

 

[1_v8_merc]

What color is the spark?
What do the plugs look like?

If you're just getting a weak White arc, or orange, not good. It should be blue.
You should be able to place the plug near the head, and it should jump between them easily.

 

[zaipai]

All good starting points thanks. I will try a couple of them today and see where it gets me. I did not notice the color, but it seem to jump from the electrode to the ground easy and pretty well. However I did not compare it to the other plugs to see if its weaker or not. The carbs were just professionally rebuilt because the jets were so plugged that even soaking them for days did not clean them up and I was in over my head so I paid some one I know who is very good at this to rebuild them. I will however check to be sure there is gas in the bowl if the problem does not follow to the #4 when I switch them around. I also need to look up how to set the timing as it has no points I am not sure.. However swapping out the plug wires seems the quickest thing to start with. I will post some thing later tonight with what I found out. Thanks all of you for jumping in...
Scott..

 

[Seana23]

hi babes. when i refit my carbs i always find that the carb bowls dont fill up evenly (the outside 2 are always a bit sluggish... with number 1 slower still than 4)...
so what i do is undo all the float bowl drain screws and turn the engine til each one starts to run with fuel (quickly do them up as this happens)...
if fuel doesnt come out ov 1 & 4 then i cover each carb mouth to create a strong vacume...
this usually works to prime them before i attempt to start the bike properly...
if this isnt imedeately succesfull then i spray a bit ov Easy-start across the open carb mouths (or into the airbox etc)...
that pretty much guarentees success.

good luck.
xxx

 

[zaipai]

Well I swapped out the sparkplug wires (was not easy, no1 was shorter then no 4) and ran it. Then pulled the No1 plug and it was wet. I also noticed that it was black where as the others are more tan. After swapping out the plug wires I noticed that No1 was warmer not room temp as it was before however not nearly as hot as the other 3. I swapped out the plug for No 4 since it was the easiest to get to ran it for a bit and noticed that it was wet where it was not wet on No. 4. Also I noticed drips under my bike, at first I thought it was oil, but its coming from the exhaust (stock 2 into 2 exhaust) coming from No1 and No2 pipes right where the clamp is. After taking it out for a quick ride, it does not seem to be doing that any more. So I put a few drops of water on the exhaust and on no 1 it just beads up and runs off, on No 2,3 and 4 it nearly evaporates.. so its clearly not running as hot, the plug is now not as wet..still wet looking tho. The other thing is the idle is a bit more unstable, gong form 2k down to 1k and back again.... I think I may have more issues then I realised. The plugs are all new and seem to have around the same gap 28, all this was done while on the center stand, I don't trust the kickstand all that much. I checked and all the bowls seem to have gas, when I loosen the screw on the bowls enough, gas starts streaming out. While I am not a complete noob, I have been working on my own bikes for 30+ years so I know the basics this one has me stumped.. I bet a good bike mechanic would have it figured out in no time.

Back to poke around a bit and see what else I come up with.

Thanks,
Scott..

P.S.
When accelerating normally it seems to miss or cut out a bit however if I get on it and twist the throttle it smooths out.. might be a different issue but thought I would mention it.

 

[49er]

Well I swapped out the sparkplug wires (was not easy, no1 was shorter then no 4) and ran it. Then pulled the No1 plug and it was wet. I also noticed that it was black where as the others are more tan. After swapping out the plug wires I noticed that No1 was warmer not room temp as it was before however not nearly as hot as the other 3. I swapped out the plug for No 4 since it was the easiest to get to ran it for a bit and noticed that it was wet where it was not wet on No. 4. Also I noticed drips under my bike, at first I thought it was oil, but its coming from the exhaust (stock 2 into 2 exhaust) coming from No1 and No2 pipes right where the clamp is. After taking it out for a quick ride, it does not seem to be doing that any more. So I put a few drops of water on the exhaust and on no 1 it just beads up and runs off, on No 2,3 and 4 it nearly evaporates.. so its clearly not running as hot, the plug is now not as wet..still wet looking tho. The other thing is the idle is a bit more unstable, gong form 2k down to 1k and back again.... I think I may have more issues then I realised. The plugs are all new and seem to have around the same gap 28, all this was done while on the center stand, I don't trust the kickstand all that much. I checked and all the bowls seem to have gas, when I loosen the screw on the bowls enough, gas starts streaming out. While I am not a complete noob, I have been working on my own bikes for 30+ years so I know the basics this one has me stumped.. I bet a good bike mechanic would have it figured out in no time.

Back to poke around a bit and see what else I come up with.

Thanks,
Scott..

P.S.
When accelerating normally it seems to miss or cut out a bit however if I get on it and twist the throttle it smooths out.. might be a different issue but thought I would mention it.

I think your problem is carb related. You say that the idle hunts up and down from 1k to 2k, this usually indicates that you have an air leak in the induction system. Did you replace the o rings between the head and the inlet manifolds? Did you check their rubber for hardness or cracking? Also your performance off idle and transitioning into the needle is hesitant. This and the low heat at #1 header pipe points to a partially blocked pilot circuit on that bank. You may need to clean those carbs again.

 

[zaipai]

Ok 49er, perhaps I will do that, I did replace the o-rings last fall and the boots are not new soft but don't seem very hard I don't see any cracks. I looked at the speed-o and it is at 36k I guess I put more miles on it then I thought. Anyway I believe they are the original boots, so maybe its time to bite the bullet and replace those when I have the carbs redone. Maybe I will have the shop that rebuilt them look them over again cause if that is the case, then they should fix it for free since I paid to have them completely rebuilt and cleaned. Below is a link to a video of it starting right after a 3 mile ride trying to figure out what?s going on. The idle here is pretty stable, but only because its super warm or because I just had it out for 10min at 55mph.. either way it seem to smooth out. I will see tonight after work if the idle is still up and down like it was. Down by the shifter is where the leak was, its not doing that any more so..

http://www.youtube.com/watch?v=OKV72thxO2k

Thanks,
Scott

I think your problem is carb related. You say that the idle hunts up and down from 1k to 2k, this usually indicates that you have an air leak in the induction system. Did you replace the o rings between the head and the inlet manifolds? Did you check their rubber for hardness or cracking? Also your performance off idle and transitioning into the needle is hesitant. This and the low heat at #1 header pipe points to a partially blocked pilot circuit on that bank. You may need to clean those carbs again.

 

[49er]

Ok 49er, perhaps I will do that, I did replace the o-rings last fall and the boots are not new soft but don't seem very hard I don't see any cracks. I looked at the speed-o and it is at 36k I guess I put more miles on it then I thought. Anyway I believe they are the original boots, so maybe its time to bite the bullet and replace those when I have the carbs redone. Maybe I will have the shop that rebuilt them look them over again cause if that is the case, then they should fix it for free since I paid to have them completely rebuilt and cleaned. Below is a link to a video of it starting right after a 3 mile ride trying to figure out what?s going on. The idle here is pretty stable, but only because its super warm or because I just had it out for 10min at 55mph.. either way it seem to smooth out. I will see tonight after work if the idle is still up and down like it was. Down by the shifter is where the leak was, its not doing that any more so..

http://www.youtube.com/watch?v=OKV72thxO2k

Thanks,
Scott

Scott, that throttle response on the video sounds quite crisp, and it has a steady idle. There's no way that a pot was down during that period of running. However, once the load of riding is applied, a leaning engine will stutter/hesitate under hard acceleration.

Before removing the carbs, I would richen up the #1 air screw and see if that improves the response under load.

 

[zaipai]

Hi all.. Well I was puttering around the garage last night when I think I figured out my issue. In fact I am rather embarrassed if it turns out that is what it turns out to be.

Well went into the garage to get out of the rain and have a smoke. While looking at the bike I relized that the bike was on the kick stand, then I noticed the glass for the oil level was full.. so I placed it on the center stand.. Same thing.. I also noticed that the oil looked really black, given that I just did an oil change that seemed a bit odd. So doing a little checking, the oil had a bit of a gas smell..

Who can guess what I did wrong..?

That's right, I put almost a quart too much oil in the bike. So I am thinking that the No1 cylinder is not firing correctly because its getting oil in it, that would explain the black plug and that it was wet even tho it has spark, it would also explain why it was slightly cooler then the other cylinders. Tonight if I get time I will drain the oil and put the proper amount in it. I found out in my Clymer manual it says to use 3qt's run the bike until warm, then let stand for 2min then check the oil level.. I never did that I filled the oil until I saw it in the window.. So its at least a qt over.

So my next question is, if this is the issue, why just No1? Is there a ring issue?

Thanks,
Scott..

Also I will be repainting the bike this winter, any thoughts on color?

 

[Guest]

As far as the gas smell in your oil, and the fact your oil level is too high.
You didn't by chance leave your petcock in prime?
Not sure exactly what type of petcock you have, but I did find this in the owners manual.
http://www.mtsac.edu/~cliff/storage/gs/GS1000G_Owners_Manual_80.pdf

You should read the caution on page 17 about leaving the petcock in Prime, it could flood your carbs.

Anyway, you could syphon down your oil level if you have some plastic tubing by carefully sticking the tube in the oil filler hole. I have done this myself, but don't do it with the engine hot as it will melt your tubing.
On the centerstand your oil level should read at the full mark.
If you got gas in your oil, you need to change it, otherwise some very bad things can happen.

 

[bubby]

do a compression test on all 4 cylinders im curious to see what the numbers are for #1 cylinder campared to 23 and 4 they should be within 10% of each other dont forget to open the throttle to wop i have a vacuum petcock so i unplug the vacum line and drain the carbs

 

[zaipai]

Well I don't have a compression tester, maybe I could find some one with one. I have a couple of friends that work on bikes for a living, surely one of them would have one.

Yes, I did leave on prime, in fact its there now, I will go out in a few and switch it to on..

I did change the oil, it had a really strong gas smell.. I drained the oil tonight and according to the manual it should take 3 quarts, so I followed the instructions and its only just showing in the window, so I will let it sit over night and see where it is in the morning.

Its still putting out blue smoke from the exhaust on the left, that goes to no 1 and 2 cylinders, when I rev it up. Not a lot of smoke out of the right side exhaust. I could not take it for a ride tonight, so I will do that Friday when I am off and see how it acts after riding it around. Maybe I will have a compression tester by then.. Stay tuned...

TTYS,
Scott..

 

[Guest]

Well I don't have a compression tester, maybe I could find some one with one. I have a couple of friends that work on bikes for a living, surely one of them would have one.

Yes, I did leave on prime, in fact its there now, I will go out in a few and switch it to on..

I did change the oil, it had a really strong gas smell.. I drained the oil tonight and according to the manual it should take 3 quarts, so I followed the instructions and its only just showing in the window, so I will let it sit over night and see where it is in the morning.

Its still putting out blue smoke from the exhaust on the left, that goes to no 1 and 2 cylinders, when I rev it up. Not a lot of smoke out of the right side exhaust. I could not take it for a ride tonight, so I will do that Friday when I am off and see how it acts after riding it around. Maybe I will have a compression tester by then.. Stay tuned...

TTYS,
Scott..

Leaving it on Prime can overflow your carbs with gas, and allow gas to get into your crankcase increasing the volume of oil/gas in your crankcase.
Oil capacity is 3.2 quarts without changing filter or 3.5 quarts if you replace filter. Put bike on centerstand and check the level in the sight glass. Once you get the required level run the bike a few minutes and let it sit awhile then recheck the level again and add if needed.
I like to keep mine just below the upper level mark.
Do not leave your petcock on "Prime" without the engine running for too long a time, just asking for trouble if you do.
Check page 16 in that owners manual (the link is in a previous post in this thread) and it shows the lever for the petcock positions. We've had several instances where people got the Prime and Reserve positions mixed up.

 

[zaipai]

Leaving it on Prime can overflow your carbs with gas, and allow gas to get into your crankcase increasing the volume of oil/gas in your crankcase.
Oil capacity is 3.2 quarts without changing filter or 3.5 quarts if you replace filter. Put bike on centerstand and check the level in the sight glass. Once you get the required level run the bike a few minutes and let it sit awhile then recheck the level again and add if needed.
I like to keep mine just below the upper level mark.
Do not leave your petcock on "Prime" without the engine running for too long a time, just asking for trouble if you do.
Check page 16 in that owners manual (the link is in a previous post in this thread) and it shows the lever for the petcock positions. We've had several instances where people got the Prime and Reserve positions mixed up.

Thanks, I put back to on. Not really sure why I had it on Prime but just kinda left it there. That would explain the gas smell and really there seemed to be more oil volume that came out of the engine when I drained it then what I put in.. All this explains a lot. Its raining today.. So I will post an update Friday or Saturday depending on weather on how this all plays out..

Thanks for the help all.. I hope this takes care of the issue.

Scott..

 

[wanrep]

You have a leaking float valve on #1 carb.
The shop that rebuilt your carbs should have replaced all the float valves. If they did, a bit of dirt/rust found it's way to the #1 carb and is causing the float valve to leak and gas to run down the cylinder, into the crankcase.
This causes all the symptoms you describe.

If the float valves are doing their job, you can leave it on "prime" forever without gas leaking into the crankcase.

You can try removing the drain screw in the float bowl, turning petcock to prime and let the gas run out for a few seconds. this might flush any debris off the float needle.
If the float valve still leaks, replace the float valve with a new one.

btw...check your air filter. I'll bet it's gas soaked.

 

[Steve]

OK, I have taken the time to read through all of these responses and am somewhat surprised that nobody has brought up a favorite topic. :-k

You say the carbs were "professionally rebuilt". Any idea what all they did to them? Did they replace all the o-rings inside? Did they replace any jets?

Most importantly, though, did you synchronize the carbs ON THE BIKE?

A good shop would have attempted a "bench sync" on the carbs before handing them back to you, but that is only a close guess. They HAVE to be synchronized on the bike. It is quite possible that your #1 carb is simply opening just a tad later than the others, meaning that it's not open as far, or not making as much heat as the others.

.

 

[chuck hahn]

I would also, to add to Steves response, double check theres that washer under each of the float seat, recheck the float heights yourself, And under no circumstances ever leave the petcock on prime or reserve when its just sitting. The only time PRI is needed is i the bike has sat for a week or 2 without running...gas will evaoporate out the vent tubes and you reprime it for a few seconds befote starting. OR if youve completely ran out of gas even on reserve or if you have to drain the carbs for maintenace issues. Other than these reasons, the petcock should always be in the ON position. Also check to see if they put rubber plugs back in on all the pilot jet holes.