Rebuilt carbs #1 not firing.

[Guest]

I got the ground sorted out, thanks to all. The carbs got left with fuel in the and we all know that means a cleaning. Here is what I have done

Disassembled all 4 and cleaned with cleaner. No dipping, they were not that bad. Cleaner came out of all the correct places.

Reassembled and installed.

Run motorcycle on aux tank, vent plugged. #1 cylinder after 5 minutes I could grab a hold of and bike was clearly dragging that cylinder.

Recheck carb for cleanliness and reinstalled

Better, now burned my hand, but had to run at 5000rpm to get heat, bought temp gauge/thermometer.

R2 carbs again.

Ran bike and took temps on header pipes. Stock exhaust

1) 87F
2 - 4)202F

No change with choke, or start lever to start. In fact the bike started cold without choke.

So I have cleaned the carbs
Swapped spark plugs
Compression 125psi
Swapped coil wires 1 and 4
Sprayed starting fluid no luck
Coil secondary resistance 24.7k
Caps are good
Plugs are sparking
Plugs black I would expect this until it goes down the road for a while.
Intake boots replace 2008, not 5000 miles since.

It seems to run better cold and I wonder, as I just read in another thread, if the vent is plugged and there is some sort of vapor lock going on. I say this because at the end last night I ran the fuel out of the carbs as much as possible, and #1 had more fuel than the rest. I did not even think about putting cleaner or air down the vent tube so...

Out of ideas.

 

[Guest]

prepare yourself for the "if they didn't get dipped...." posts. That said, and knowing the compression is ok, have ya checked valve clearances? you mention more fuel in # 1, what are the float levels?

 

[hannibal]

Is the bike on the side stand? You could be getting too much fuel in #1, causing it to run rich and cooler.

 

[tom203]

Not doing the full Monty dipping and new o-rings on the carbs is risky....#1 could have leaky fuel needle seat, overfilling bowl, and causing plug fouling ....also since it has been sitting , pilot circuits could be gummed up - no matter how clean they appear

 

[Steve]

The carbs got left with fuel in the and we all know that means a cleaning. Here is what I have done

Disassembled all 4 and cleaned with cleaner. No dipping, they were not that bad. Cleaner came out of all the correct places.
...

Ran bike and took temps on header pipes. Stock exhaust

1) 87F
2 - 4)202F


Out of ideas.

OK, you admit you took a shortcut. Any shortcut taken are only opportunities to do it over and do it RIGHT.

Other than the fact you have four cylinders, I don't have a clue what bike you are talking about.

I am therefore out of suggestions.

.

 

[Guest]

OK, you admit you took a shortcut. Any shortcut taken are only opportunities to do it over and do it RIGHT.

Other than the fact you have four cylinders, I don't have a clue what bike you are talking about.

I am therefore out of suggestions.

.

Those are the temps of the header pipes in degrees. I got tired of burning my hand.

 

[Guest]

Not doing the full Monty dipping and new o-rings on the carbs is risky....#1 could have leaky fuel needle seat, overfilling bowl, and causing plug fouling ....also since it has been sitting , pilot circuits could be gummed up - no matter how clean they appear

Pulled it replace the o-ring. The was replaced in 2008, so less than 5000 miles on it. I really am hoping to avoid a complete tear down, all passages seem clean. I do realize what you say is true though. Thank you.

 

[Guest]

Is the bike on the side stand? You could be getting too much fuel in #1, causing it to run rich and cooler.

Center stand.

 

[Guest]

Thank you all for you replies. I took the airbox apart. Both sides off, the opened the garage door, and pulled the air filter out. It was soaked with rancid smelling gas, (why I opened the door). It was visibly wet on the #1 side. I gave it a good squeeze soaking 2 shop towels, and it is airing out. Carbs are again on the bike.

Float level, while I was at it checking the needle valve I checked the float height. Spec is .88in +/- .04. Mine .90in.

There is a hose from the upper chamber of the airbox that is old and doesn't stay anymore not sure how important that is with these fussy carbs.

Valve clearances good, set in 2008, not been 1000 miles since. I did set one just a little loose and it is clattering so may go back in and see, may have to buy a shim because I don't think I have one and why I set it a little loose one to two thousands is all

Again Thank-You all for the help.

 

[Steve]

A wet air filter is usually the result of a sticky float that lets fuel in.

The hose on top of the airbox is the crankcase breather hose from the top of the valve cover. It's good to have.

Loose valves are good, up to a point. Spec is 0.03-0.08mm (roughly 0.001-0.003"), but many of us will go up to 0.10mm or 0.004".

Your reply in post #6 still doesn't tell what bike you have. Post #1 mentioned temps on four header pipes. Post #6 confirmed that they were header temps. The only thing we really know for sure is that it's not a GS450.

There are suggestions that could be made, but there were many differences between years, engine displacements and carbs.
I, for one, am not going to sit here and list them all, so please give us a clue what bike we are discussing.

.

 

[alke46]

If you didn't dip and run a small wire through the passages then you can't know the passages are really clean.

 

[Guest]

A wet air filter is usually the result of a sticky float that lets fuel in.

The hose on top of the airbox is the crankcase breather hose from the top of the valve cover. It's good to have.

Loose valves are good, up to a point. Spec is 0.03-0.08mm (roughly 0.001-0.003"), but many of us will go up to 0.10mm or 0.004".

Your reply in post #6 still doesn't tell what bike you have. Post #1 mentioned temps on four header pipes. Post #6 confirmed that they were header temps. The only thing we really know for sure is that it's not a GS450.

There are suggestions that could be made, but there were many differences between years, engine displacements and carbs.
I, for one, am not going to sit here and list them all, so please give us a clue what bike we are discussing.

.

Sorry of course what bike I am talking about would be helpful, my fault. 1982 GS 850G.

I know the breather hose, this hose is on the left side and is a drain. Being old it slips out of the hole in the upper part of the airbox. Just not sure how important it is in the big scheme of things.

I had a feeling there might be a sticky float having had that gas left in. They all look free on this last cleaning, I will leave the airbox off, put the aux tank and see if fuel comes out, and where. Also, I forgot to mention that before this last superficial cleaning a good amount of starting fluid was used, but the filter didn't smell like starting fluid, it was definitely bad gas.

 

[Guest]

If you didn't dip and run a small wire through the passages then you can't know the passages are really clean.

I did, .020 safety wire. BUT it, from doing this before was not the straightest piece so I didn't force it. I meant to get some new yesterday at the hardware store and forgot. I have .032, But I feel that it too big. No dip, just wire.

 

[Rich82GS750TZ]

I know the breather hose, this hose is on the left side and is a drain. Being old it slips out of the hole in the upper part of the airbox. Just not sure how important it is in the big scheme of things..

This is not a drain. This is a vent. If you see gas coming out of these, you definitely have a stuck float, bad petcock, or both. And you'll have gas in other places it's not supposed to be.

 

[Guest]

Not doing the full Monty dipping and new o-rings on the carbs is risky....#1 could have leaky fuel needle seat, overfilling bowl, and causing plug fouling ....also since it has been sitting , pilot circuits could be gummed up - no matter how clean they appear

Very true. AND at 38 years old it may be time for a complete rebuild.

A little history. I bought it in 1992, it had sat for 10 years the dealer told me. It wasn't right then, they cleaned the carbs. Rode it to 25,000 miles or so, life happened and I parked it...and rodents made a home in the airbox, above the filter. One of the slides, #3 if I recall was completely frozen, carbs rebuilt this was 2007ish, (replaced slide). Used bike until 2010, shipped to the UK and rode for 200 miles, parked again. Shipped to AZ. Fired right up with old UK gas, ran great! Parked for the off season, did not drain carbs. Then one day I was passing 2 tractor trailer trucks, had a car right on my rear, concrete barriers to my left and 2 cylinders cut out! Parked it in spring 2017, thinking it might be the stator. Bought a Harley. Harley does not clear speed bumps or some of the places AZ lets washes cross the road so I decided to fix the 850. Last parked I didn't drain the carbs (how stupid).

I had also totally fried the body ground wire in 1992, and had suffered from sometimes all cylinders fired, sometimes I had to wiggle the main harness. I just fixed that (replaced the wire) and am also in the process of cleaning and lubing the harness connectors.

 

[Guest]

This is not a drain. This is a vent. If you see gas coming out of these, you definitely have a stuck float, bad petcock, or both. And you'll have gas in other places it's not supposed to be.

I had a feeling that was what it was. I was at a loss to describe it so I went to Babbits fiche for nomenclature. I will get a new one, this one is hard.

 

[Guest]

So here is what I see to be the theme or cause of my problem. I fail to drain the carbs. Why? It is a pain in the butt and messy. I am a previous Honda owner they had nice drains with hoses that I could easily drain. The 850, I have to cram something under the carbs then try to reach the drain plugs of 2 and 3, gas goes everywhere. Tried my Harley oil filter drain without success, going to try a small bread pan. Maybe a flexible cutting board to funnel the fuel to a container? Last time I gave up and put a shop towel on the engine and let the drains go.

 

[Rich82GS750TZ]

I had a feeling that was what it was. I was at a loss to describe it so I went to Babbits fiche for nomenclature. I will get a new one, this one is hard.

Just to be clear, your carbs have 2 vent hoses, just get both.

 

[allojohn]

And you'll have gas in other places it's not supposed to be.

Just making sure you didn't miss this pvasc.... you could have gas in your crankcase.

 

[Guest]

Just making sure you didn't miss this pvasc.... you could have gas in your crankcase.

I could, I don't smell it though. It happened before when the petcock failed. New petcock 2007ish.