No 1 Cylinder not getting warm

[Guest]

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

I would like to agree with you, but then there's that caution in the owners manual. In fact it's in most owners manuals for the GS series bikes. Now why would Suzuki put that in there for a serviceable bike? I've argued this point before and it's just best to not leave it in "Prime." It very well could be when the bike is on it's sidestand the bike is at an angle and the floats don't come up high enough to provide a good shut off.

 

[chuck hahn]

Steve...I see he has only 2 posts so far...sooner or later he will see the light. The steel points of the needles arent machined so precisely to seal like say an oring would. Secondly, the needles are steel and the float seats are softer brass..thus the softer brass does inccur wear over a sustained period of time. These two realities in and of themselves are reasons the owners manual warns directly about leaving it on prime. Then you factor in the petcock seals and diaphrams wear and can fail almost at any time...see what I mean???

 

[zaipai]

The shop that did my work is one I have used before and is a friend. He does really good work, I trust he rebuilt them well. I gave him a rebuild kit I bought for it, he did the rest. Below is a link to a CafeTV that featured some of his work, its short, only 1min or so but you can see he is a stickler for details.

I did put the petcock back to On from Prime. I think I set it on Prime after I put the carbs on and forgot to put it back, this is my first experience with a vacuum petcock so still finding out about them and how they work etc..

He did do a bench sync after he rebuilt them. I have a vacuum carb sync tool I used on my Honda cb550 so I will get to sync'ing these carbs, its really been more a time issue for me. Sounds like I need to do that sooner rather then later..

Thanks for all the advice I am looking all of it and will take all advice that comes my way..

https://www.youtube.com/watch?v=MOF9hyOSEsQ

TTYS,
Scott..

 

[koolaid_kid]

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

I would like to agree with you, but then there's that caution in the owners manual. In fact it's in most owners manuals for the GS series bikes. Now why would Suzuki put that in there for a serviceable bike? I've argued this point before and it's just best to not leave it in "Prime." It very well could be when the bike is on it's sidestand the bike is at an angle and the floats don't come up high enough to provide a good shut off.

Forever is a long time. Whilst I have left it on virtual prime (Using an aux tank while tuning the carbs) for hours, even overnight when I forget to remove it, I would not leave it on all the time.
My GS manual had the warning, my GPz manual does not, and they both use BS34 carbs. But I still don't leave it on prime, that is the whole function of the vacuum petcock.

 

[Guest]

Steve...I see he has only 2 posts so far...sooner or later he will see the light. The steel points of the needles arent machined so precisely to seal like say an oring would. Secondly, the needles are steel and the float seats are softer brass..thus the softer brass does inccur wear over a sustained period of time. These two realities in and of themselves are reasons the owners manual warns directly about leaving it on prime. Then you factor in the petcock seals and diaphrams wear and can fail almost at any time...see what I mean???

Chuck,
That's a great explanation of the potentially inherit weaknesses of the float needles and seats. I would also think that the pressure that builds in the tank after riding, or from the bike sitting in the sun would put those needles and seats under more pressure and what would otherwise be a small gravity leak could be compounded even more.

 

[Guest]

Forever is a long time. Whilst I have left it on virtual prime (Using an aux tank while tuning the carbs) for hours, even overnight when I forget to remove it, I would not leave it on all the time.
My GS manual had the warning, my GPz manual does not, and they both use BS34 carbs. But I still don't leave it on prime, that is the whole function of the vacuum petcock.

Forever is a long time.
And it also has been a very long time since I clearly remember entering into a discussion with you on this very same subject.

 

[MisterCinders]

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

That's a pretty big "IF." Why would Suzuki bother with a vacuum petcock, if the float valves are so reliable? Why do other bikers turn off their gravity fed petcock when they park the bike? Superstition?

If the float valve still leaks, replace the float valve with a new one.

If I follow you, he should flush the bowl, check for leaks, and then replace the "float valve." That's pretty expensive, depending on what a "float valve" is. An OEM float needle/seat assembly is pricey. The ones in the kits are junk.

Before you shell out for a new float needle and seat, there are a few other things to inspect for leaks.

1. Clean the seat and the float needle to make sure nothing is blocking it.

2. Check the float needle for wear. If you can feel a ridge on the point, replace that needle (you can get replacement float needles from Z1).

3. Check the needle and seat together for seal. Blow into the bottom of the seat as you slowly slide the needle into it. You should feel it close as your cheeks puff out like blowing up a balloon. If it doesn't seal, then you might need to go back to the needle or replace the set.

4. Check the float itself to make sure it is not catching on something like a bowl gasket edge).

5. Check the washer for the needle seat. These can fail, and let gas flow unchecked. If so, replace that washer.

 

[wanrep]

I'm new here but not to motorcycle carburetors. I've rebuilt more sets of GS carburetors than I can count.
Fact remains, it doesn't matter if the petcock is on "on" or "prime", if the float valve's leaking, that cylinder is going to flood and run rich when it's running.
No, it won't flood the crankcase if it's on "on" while sitting (until the petcock starts leaking which they all do at some point) but it's still not going to run correctly.

If Zaipai fixes the #1 float valve, it won't matter if he accidentally leaves the petcock on prime. The other 3 plugs looked good, right?

Just a side note...I've replaced the vacuum petcock on every bike I've had with a Pingel, manual on/off/reserve, petcock and I do turn it off.

 

[tom203]

I'm new here but not to motorcycle carburetors. I've rebuilt more sets of GS carburetors than I can count.
Fact remains, it doesn't matter if the petcock is on "on" or "prime", if the float valve's leaking, that cylinder is going to flood and run rich when it's running.

But when engine is running, fuel is dribbling thru seat and into bowl at all times, so slight leakage at needle seat would not cause the cylinder to run rich. I bet lots of these old carbs (like mine) probably have worn seats- unnoticeable provided we don't leave it in "Pr" and petcock is working right

 

[wanrep]

That's a pretty big "IF." Why would Suzuki bother with a vacuum petcock, if the float valves are so reliable? Why do other bikers turn off their gravity fed petcock when they park the bike? Superstition?



If I follow you, he should flush the bowl, check for leaks, and then replace the "float valve." That's pretty expensive, depending on what a "float valve" is. An OEM float needle/seat assembly is pricey. The ones in the kits are junk.

Before you shell out for a new float needle and seat, there are a few other things to inspect for leaks.

1. Clean the seat and the float needle to make sure nothing is blocking it.

2. Check the float needle for wear. If you can feel a ridge on the point, replace that needle (you can get replacement float needles from Z1).

3. Check the needle and seat together for seal. Blow into the bottom of the seat as you slowly slide the needle into it. You should feel it close as your cheeks puff out like blowing up a balloon. If it doesn't seal, then you might need to go back to the needle or replace the set.

4. Check the float itself to make sure it is not catching on something like a bowl gasket edge).

5. Check the washer for the needle seat. These can fail, and let gas flow unchecked. If so, replace that washer.

You're right. All the aftermarket float valves I've tried over the years are junk.
I always use Suzuki's but yes, they are pricey at $33. Never had one leak though.
When I rebuild an old set, I replace all the float valves with new ones.
I put them on a carb rack with a remote fuel supply and let them sit for an hour with the gas on to make sure there's no leaks.
It's pricey but I've never had a bike come back with carb issues.

Zaipai's issue may very well be a speck of dirt in the float valve causing it to hang open. I'd start there first. If, after all cleaning and adjusting fails, then replace the float valve.

By all means fella's, turn those petcocks off. I still turn mine off.
BUT...it shouldn't be disastrous if you accidentally leave it on. That's all I'm saying.

 

[chuck hahn]

Steve..if the caps vent hole isnt stopped up, the ambient pressures should be on a constant self leveling scenario. Regardless if its sun heat or engine heat, the venting should allow for all fluctuations one way or another.

 

[wanrep]

But when engine is running, fuel is dribbling thru seat and into bowl at all times, so slight leakage at needle seat would not cause the cylinder to run rich. I bet lots of these old carbs (like mine) probably have worn seats- unnoticeable provided we don't leave it in "Pr" and petcock is working right

Depends on how bad it's leaking. Sounds like his is leaking bad or stuck open to be that flooded.

Slight leakage is more noticeable at idle and not at all on the highway.
The bike never runs "that bad" and as long as the petcock does it's job, a guy will never suspect leaking until the petcock fails and he finds an overfull crankcase.

 

[zaipai]

I'm new here but not to motorcycle carburetors. I've rebuilt more sets of GS carburetors than I can count.
Fact remains, it doesn't matter if the petcock is on "on" or "prime", if the float valve's leaking, that cylinder is going to flood and run rich when it's running.
No, it won't flood the crankcase if it's on "on" while sitting (until the petcock starts leaking which they all do at some point) but it's still not going to run correctly.

If Zaipai fixes the #1 float valve, it won't matter if he accidentally leaves the petcock on prime. The other 3 plugs looked good, right?

Just a side note...I've replaced the vacuum petcock on every bike I've had with a Pingel, manual on/off/reserve, petcock and I do turn it off.

Yes, the other 3 cylinders plugs are a light tan, the No1 cylinder was black and slightly wet. The no1 is firing it gets warm, just not as much as the others. I was thinking that since I had the oil level so high that it was keeping the no 1 cylinder from sparking enough to actually fire the gas/air mixture and the excess gas was falling into the crank case from there. Is that even possible? I will remove the float bowl and check all that was mentioned so I can either find the problem or rule those out. That is actually not that hard of a thing to do. I will also check the compression on each and vacuum sync the carbs (tho getting the screws loose on the intake manifold is going to bite). I will try and snap a picture of the plugs and get some video of the exhaust so you can see the smoke, funny tho after about 5 min of riding the smoke seems to go away, as in the video I first posted, you will note that even at high revs all that came out was just a little black smoke. However (choke completely off) when I rev it before I ride it there is blue smoke mostly just out the left exhaust.

I did get the rebuild kit from Z1 I believe..
This is what I bookmarked so likely it is what I ordered. I got the kit over a year ago, even tho it was only used a few weeks back at the end of June.
http://www.z1enterprises.com/ItemDetails.aspx?item=KL18-2582

Thanks,
Scott..

 

[chuck hahn]

If there4 was enough oil bypassing the rings to foul the plug the way you describe youd most limkely have a big white smoke mosquito fogger as well. I dont think its oil..i think its a combination of bad plug and whatever reason is causing the extreme fuel flow. Clean the plug real well or better yet replace that black one and take her for a ride...say 25 or 30 miles and then see what the color changes are in that cylinder.

 

[Guest]

Steve..if the caps vent hole isnt stopped up, the ambient pressures should be on a constant self leveling scenario. Regardless if its sun heat or engine heat, the venting should allow for all fluctuations one way or another.

True, but in case of extreme hot, I had it build up quicker than it could vent.

 

[wanrep]

Yes, the other 3 cylinders plugs are a light tan, the No1 cylinder was black and slightly wet. The no1 is firing it gets warm, just not as much as the others. I was thinking that since I had the oil level so high that it was keeping the no 1 cylinder from sparking enough to actually fire the gas/air mixture and the excess gas was falling into the crank case from there. Is that even possible? I will remove the float bowl and check all that was mentioned so I can either find the problem or rule those out. That is actually not that hard of a thing to do. I will also check the compression on each and vacuum sync the carbs (tho getting the screws loose on the intake manifold is going to bite). I will try and snap a picture of the plugs and get some video of the exhaust so you can see the smoke, funny tho after about 5 min of riding the smoke seems to go away, as in the video I first posted, you will note that even at high revs all that came out was just a little black smoke. However (choke completely off) when I rev it before I ride it there is blue smoke mostly just out the left exhaust.

I did get the rebuild kit from Z1 I believe..
This is what I bookmarked so likely it is what I ordered. I got the kit over a year ago, even tho it was only used a few weeks back at the end of June.
http://www.z1enterprises.com/ItemDetails.aspx?item=KL18-2582

Thanks,
Scott..

Scott,
What happens is, gas fills up the carb but the float valve doesn't shut it off at the right level and gas continues to fill up and out into the mouth of the carb. On other carbs there was an overflow pipe that'd put all that excess gas on the ground.
Since the carbs are tilted slightly toward the engine, the gas runs into the cylinder (if the intake valve is open). The gas washes all the oil off the cylinder, leaks past the rings, down into the crankcase.
Now, when you start the bike, that cyl. burns the excess gas left in the cyl. plus oil that's pushed up from the crankcase past the rings. This will happen regardless if the crankcase is over full or not.
Once it's run for a little bit, the oil ring reseals itself with fresh oil and it stops burning any oil.
This really doesn't harm the rings so don't worry about that.

I'm starting to wonder if your float might be stuck. Try tapping (lightly)on the side of the carb with a rubber hammer or the handle of a screwdriver.
You'll have to take the airbox off, turn the fuel on to prime and look down the carb to see if fuel is running into the throat.

 

[zaipai]

Scott,
What happens is, gas fills up the carb but the float valve doesn't shut it off at the right level and gas continues to fill up and out into the mouth of the carb. On other carbs there was an overflow pipe that'd put all that excess gas on the ground.
Since the carbs are tilted slightly toward the engine, the gas runs into the cylinder (if the intake valve is open). The gas washes all the oil off the cylinder, leaks past the rings, down into the crankcase.
Now, when you start the bike, that cyl. burns the excess gas left in the cyl. plus oil that's pushed up from the crankcase past the rings. This will happen regardless if the crankcase is over full or not.
Once it's run for a little bit, the oil ring reseals itself with fresh oil and it stops burning any oil.
This really doesn't harm the rings so don't worry about that.

I'm starting to wonder if your float might be stuck. Try tapping (lightly)on the side of the carb with a rubber hammer or the handle of a screwdriver.
You'll have to take the airbox off, turn the fuel on to prime and look down the carb to see if fuel is running into the throat.

Ok I will try that it sure sounds like what is going on.. Here is an image of the plugs.. No 2 and no 4 look like they should, rather tanish.. No 3 is a little darker but not too bad.. No 1 is black as coal and rather shiny. This is how there were before the video I took tonight. I cleaned them all up as best I could and put them back in. Video to follow..

http://zaipai.dlinkddns.com/plugs.JPG

Thanks,
Scott..

 

[zaipai]

Ok this is just kicking me in the butt. Here is the video, I cleaned the plugs that is all. While the smoke is normally what it does, for some reason the No 4 cylinder was not firing. After this video I checked all the pipes and No 4 was ice cold.. I don't understand. I checked the plug wire and its fine. I cleaned the plugs using a dremel like tool with a brass wire wheel, then some 600git sand paper, gave each one a squirt of choke cleaner (its all I had) and then checked the gap and put them back in.. I don't get it. So ignore the back fires and the way it sounds, the smoke is the same and it does this all the time. After a good ride, it goes away, not completely but you can't even really see it..

http://www.youtube.com/watch?v=L4B8UkVtAPM

Scott..

 

[chuck hahn]

So your part about the smoke goes away after a good drive...but just maybe theres a slight hint still visible.....well that tells me the valve stem seals are giving up the ghost. May as well do the complete head refresh and get that over with while youve got the head off to do the seals. Heres what youll see if you look inside the spark plug caps with a flashlight..unscrew that slotted brass thing in there and remove the ceramic resistors and replace them with copper or brass rod cut to the same approximate length. NOTE::: 1 and 4 DO NOT have a spring in the caps, but 2 and 3 DO. When reassembling them, put the springs in first, then the brass replacement rod, and then screw in the brass thing. resisitors are almost 95% overlooked when it comes to spark and cylinder loss issues!!!!

 

[zaipai]

Thanks, I did not know about that. I did not find anything to replace the ceramic rods with. However the brass caps were so loose all it took was a turn and a half and they were out. So I cleaned them up and put them back in and tightened them back up. I did not touch 2 and 3 other then to tighten them since those cylinders were not giving me any issues. Anyway tomorrow I will head up to the hardware store and see what I can find to replace them.
I am hoping its not a head rebuild, that would suck. However winter is coming and that would be a good time to do it.

TTYS,
Scott...

So your part about the smoke goes away after a good drive...but just maybe theres a slight hint still visible.....well that tells me the valve stem seals are giving up the ghost. May as well do the complete head refresh and get that over with while youve got the head off to do the seals. Heres what youll see if you look inside the spark plug caps with a flashlight..unscrew that slotted brass thing in there and remove the ceramic resistors and replace them with copper or brass rod cut to the same approximate length. NOTE::: 1 and 4 DO NOT have a spring in the caps, but 2 and 3 DO. When reassembling them, put the springs in first, then the brass replacement rod, and then screw in the brass thing. resisitors are almost 95% overlooked when it comes to spark and cylinder loss issues!!!!