Fresh carb rebuild and Engine Knocking

[Maz]

I need some suggestions regarding this leaking carb:

STA76115.JPG

I checked all the carb float valves and they were working fine. I had the bowls off with the carb up-side-down (as in picture above) and blew into the gas line (put a bit of air pressure into the line) as I moved each float upward to its "open" position. When I did, I could hear the air begin to hiss out of each of the float valves. As I let the float go back down, the air stopped. So, they are all working fine based on air flow.

I then put the bowls back on, and flipped the carb right-side-up, and attached a long piece of gas line and used a bottle to add gas to the line. The carb bowls filled up, and then carb No. 3 (the one where the fuel line connects to) began to leak gas. The gas was flowing below the butterfly and dripping out the end. It was also leaking out of the brass fitting (in pic at tip of my finger), and also appeared to be leaking higher up around the carb.

STA76217.JPG

It was only leaking around the No. 3 carb until I put a screwdriver under it to tilt it some. Then, gas also leaked out of Carb. No 1:

STA76221.JPG

Here you can see alot of gas sitting in the main air box chamber, right beside Carb 3:

STA76224.JPG

I hope to get some advice as to what could be causing this big leak. I believe the float valves are working fine. Is there something else that could allow the leak assuming that all the carb float valves are closing properly?

Splitting the carbs to replace the plenum seal and O rings is a good idea, but I believe you still have a leaking float valve or a split / porous float (take them out and shake them to check for gas inside). It's also possible that the float is sticking open when the bowl is refitted, due to it fouling on something and not being able to close.
Maz

[dwight007fchr]

spiralout........Nope, I did not split the plenum when I rebuilt the carbs. I agree with you.....could be those ORings on the end of those fuel connection pipes. That would make sense because if all 4 float valves are working properly and the gas is not overfilling the carb bowls, then it could be leaking around those fuel connector pipes which have ORings.

I will have to put some dry towells around the connection pipes of No. 1 and No. 3 carbs and look for leaks as I pour gas into the temporary gas line.

But if not the connector pipe ORings, nor the float valves, what on earth could be allowing gas to leak?

Will let you know what I find out.

[dwight007fchr]

Mazzz.......Well, I put brand new float valves and seats in all the carbs, and all four plastic floats were empty and had not cracks/leaks. Also, all four float valves appear to be working fine when I blow down the gas line and test each float.

Im tempted to put some type of dye in the gas so I can see better where that clear gas is coming from. Maybe some of that AC leak dye stuff mixed with the gas, but I still would need the infrared flashlight to see it. Instead, do you think red-dyed diesel fuel would show up better when it leaks?

[spiralout]

But if not the connector pipe ORings, nor the float valves, what on earth could be allowing gas to leak?

The plenum gasket or the carb to plenum o-rings.

[dwight007fchr]

spiral........OK......I am gonna try some type of dye to locate the leak. That clear gas is just too hard to locate when searching for the leak.

[ekvh]

You can see where it's leaking by removing the slides and caps. Dry everything out, turn on the fuel and watch with a flashlight. Leaky floats allow to much fuel and will leak up through the main and primary jet openings. Carb-to-plenum orings will leak into the carb threat nearest the plenum. Watching carefully with a flashlight, you can see it pooling on that end of the slide opening before it begins running down the carb by the jet openings.

It helps if you know which intakes had fuel in them. Otherwise it takes a few tries, dryingveverything off between tries.

The seals can be replaced without full separation of the linkages.

[dwight007fchr]

ekvh......Thanks for the leak-detection tips. I know its leaking on the No. 1 and No. 3 side, and I still have the carb on the bench, so I will test as you said.

When you say "carb to plenum ORings", do you mean the ORings at the end of the small metal pipes which supply gas to the carbs?

[dwight007fchr]

ekvh......Also, the metal tube that sends gas from No. 3 carb to No. 1 carb does rotate with very little effort. You think that is a sign of worn out ORings, or is that pretty normal?

[spiralout]

When you say "carb to plenum ORings", do you mean the ORings at the end of the small metal pipes which supply gas to the carbs?

Nope, we mean the o-rings between the carb and the plenum.
I think there's a large one for each carb and a couple of smaller ones for two carbs. I'm not positive on the number, though, because I haven't repaired 1100 carbs yet.

[dwight007fchr]

spiral........I guess I am lost, and need to go look at some repair pictures showing those carb-to-plenum orings. Just way too many Orings in these carbs! To be honest, I dont know what a "plenum" is.....i guess its the "box" in the middle of all 4 carbs. Who the heck gave it the name "plenum"????

[spiralout]

Ya, the plenum is the air box the carbs bolt to. Go back and read THIS one again and you'll see what we're talking about.

[dwight007fchr]

spiral........I feel like the kid who cant swim and prefers the shallow end of the pool.......now you crazy folks want to lure me to the deep end and push me off into that will blue younder......what yall call the "plenum". Looks like I might have to learn how to swim real soon. Dern plenums.

[spiralout]

...now you crazy folks want to lure me to the deep end and push me off into that will blue younder......what yall call the "plenum". Looks like I might have to learn how to swim real soon. Dern plenums.

That's the best way to learn to swim.
I went to the shop this morning and looked at my 1100 carbs. As far as the fuel leaking out of the barb on bowl #3, that's your vacuum takeoff for the timing advance. If there's fuel there you probably have a bad bowl gasket. The gasket should be isolating that passage from the fuel.
I went back and re-read this thread, too. You said that you did a thorough cleaning and rebuild, but I don't believe it was that thorough. There is a lot more to an overhaul of 4 cylinder GL carbs than replacing the seat and needles and cleaning what you can get to with the carbs not separated. I'd normally suggest sending your carbs to Pistol Pete Services for a rebuild but In your case, I think you're capable and I'd recommend biting the bullet and spending the $224 on Randakk's (overpriced for what it is) master kit and do a complete cleaning and overhaul.

[dwight007fchr]

spiral.....Thanks for going out and looking at your 1100, and giving me some more advice. Yep, that barb off Carb 3 is the vacuum advance........does that come off that hole which has the small ORing right beside the carb bowl gasket? I put new bowl gaskets and that ORing also. The old gaskets and ORing looked fine, but they had become pretty flat/compressed and I did not want to chance them not sealing. I recall measuring the new gaskets, and they were .5mm thicker than the old ones (since they had not been compressed for 30 years.

I still need to do another test and search for the leak spot, and hopefully it is something simple.

For me, it was a pretty darn thorough cleaning/rebuild. I was not up to opening up the plenum and possibly screwing something up. Yep, I know that I can do it, but was hoping to get out of it.

See ya.

[spiralout]

........does that come off that hole which has the small ORing right beside the carb bowl gasket?

I'm not really familiar with 1100 carbs but looking at my old frozen set, it looks to me like the vac advance barb's channel goes through the larger "loop" in the bowl gasket to a passage in the carb body. The small separate o-ring on the bowl is for the accelerator pump.
If your leak turns out to be the plenum gasket, carb to plenum orings or transfer tube orings, the carbs are going to have to be separated anyway which is the time to go ahead and do a complete cleaning and rebuild.
Maybe someone with more knowledge of 1100 carbs can point you in the right direction.

[dwight007fchr]

spiral......OK.....I just need to go do some leak testing, and dig into it again. I would love to find the problem, fix it, and get her back on and running.......as she sounded so sweet when I had her running last week. Will repost when I lean more.

[dwight007fchr]

Spiral and anyone interested:

I used a stong mixture of Yamalube and gas to make a dark gas which I could see leaking better. I poured it down the fuel line, and it once again came out that vacuum tube fitting while leaking out of the side where the rubber intake boot hooks up too. See pic:

Still Leaking on Carb 3

So, I took the top vacuum cover off and removed the slide so I could peer down inside while I added gas to the fuel line. The gas came gushing up the middle hole where the vacuum slide needle fits into (see pic):

Gas gushing up from this jet hole

So I drained the gas out of the carbs so I could flip the set over to remove the carb bowl of No. 3. Everything looked good inside, but I removed the float and took out the new float valve and new brass seat. I did discover that the new miniture gas filter that is supposed to attach to the brass seat had come loose and was just sitting in the hole. When I removed it and tried to re-attach it, it did go on, but it fits so loose that it would just fall off again. So, I got the original OEM filter which was in great shape, and put that on......and it did fit nice and tight, and will not fall off. (Cheap aftermarket parts suck).

New filter that is loose and falls off

Here you can see the original Honda filter on left (smaller in size) and the new replacement filter:

OEM on left, ElCheapo on right

I also looked at the original float valve with the rubber tip and compared it to the new one that was leaking:

OEM on bottom

The original OEM is on bottom, and new one on top. The spring-loaded valve tip was a bit shorter on the old OEM one. All the other measurements were pretty dern close and probably within specs. I went ahead and used the old Honda float valve tip and tossed the new one back into the No 3 parts container. Im not sure if the loose filter could have been preventing the rubber tip of the valve from fully closing, but doubt that could happen. I rechecked the float level spec. distance which was still good, and put the bowl back on.

I put dry paper towels under the gas tubes that carry gas to the other carbs, and then poured the dark Yamalube gas down the gas line. This time NO LEAKS!!!!! July 4th fireworks are called for!

(Will give results of cranking the engine next)

[dwight007fchr]

I left the Yamalube mixture in the carb bowls and re-installed the carbs on the ole GL1100. Not a process I enjoy doing all the time, as there are specific steps/tricks to get it done right, and installing those accelerator cables are no joy either. Got her all back together, and rigged up the 1/2 gallon container with fresh non-ethanol gas.

Cranked her up, and she started right up, but was running crappy, hic-upping, and belching like someone with acid reflux. Turned her off, and realized that I had not connected the vacuum advance line.....got that back on, and cranked her up. It was a bit better, but still hick-upping and belching. Then I realized that I had not tightened any of the air intake rubber boots which connect to the metal pipes going down to the engine......got those tight, and then restarted. This time she ran smooth as hot gravey on mashed taters. Sounded great, and purrs like a kitten. However, she was throwing out alot of smoke, and I am hoping that it is just burning off that Yamalube and the oil in the vacuum slides.

The wierd thing was that there was an occasional belching noise down around No. 3, and I could have sworn that I saw a "poof" of air coming from someplace around the plug or the air intake arm. It did it a few times and then stopped.....usually it happened when I revved her up a bit and let off......kinda like a backfire. I could not get it to happen again, and was thinking that maybe the spark plugs might be loose on 1 and 3, and were loosing some gas past the threads. Turned her off, and checked the plugs......they were tight.

Belching area

So, everything seems good, except for the thick smoke. If the smoke does not stop after burning half a gallon, I might have other problems.

Smokin

[spiralout]

Splitting the carbs to replace the plenum seal and O rings is a good idea, but I believe you still have a leaking float valve or a split / porous float (take them out and shake them to check for gas inside). It's also possible that the float is sticking open when the bowl is refitted, due to it fouling on something and not being able to close.
Maz

...and Maz wins.

Glad you got the leak fixed. For some reason I was under the impression that you replaced the needles and seats with OEM. I went though similar problems on my first overhaul of 1000 carbs using Sabre Cycle's garbage Barracuda brand kits and ended up putting the old OEM needles and seats back in, too, and had to replace their bowl gaskets within a year. As far as the smoke, the more you run that motor, the less fuel it'll use and the less it'll smoke. Now you just need to put some miles on it. (and do a complete clean and overhaul of the carbs when the aftermarket carb parts start going bad =P)
Both my 1000 motors would smoke if I put the factory spec amount of oil in them until I drained a bit or it burned it down to the level they liked. Since your's is running now, I'd run some seafoam or MMO in the oil to help clean the sludge out of it and do another oil change and see how it does.

[dwight007fchr]

Also........Since one of my worries was gas getting into the engine crankcase, that problem is also gone. I put a black mark on the oil sight glass where the fresh oil was reading while on the center stand. After running and cooling down, the oil level has not changed from the black mark. So, that is also good news.

Spiral.......Yep, Maz the soothsayer was right....leaking float valve.

"outlaw racing" are the rebuild kits and "made in Tiawan" on the labels. I really should not complain, except for those gas filters which are too loose and fall off. Do you think that a filter that is tilted exactly on the center hole of the brass seat could cause the rubber float valve to not close all the way? If so, it just shows you how something as simple as a miniture gas filter can royally screw up your day.

Sabre Cycle......Me too. I ordered a bunch of stuff from them a few years ago, and they screwed me over too. I take pride in bad-mouthing those idiots who dont give a crap about customer service and continually rip-off customers.

Smoking......Im hoping that the Yamalube is just taking time to flush out the carbs, and things will start clearing up next time I run her. I also want to do another carb sync and make sure its adjusted right.

I wont be able to put some miles on her until I fix the frozen rear brakes. Hopefully an easy fix.....probably just surface rust on the brake piston.

Thanks for your input, and all the other people who gave some good tips......and to Maz for hitting the nail on the head.

[Maz]

Just glad you got it sorted and glad to be able to help. We've all been there.
Maz

[dwight007fchr]

Maz/Spiral......Yea, Im getting closer and closer to being able to drive her.

Another thing that I forgot to mention: While she was running, I used my hands to feel the temperature of all 4 intake pipes (between carbs and the engine). The No. 1 and No. 3 intake pipes were alot warmer than the No. 2 and No. 4 intake pipes. For some reason, the right side of the engine must have been running hotter. Any ideas what would cause this? Just a leaner gas mixture on the right side? (Also, the right side was the one that had that strange popping/belching noise going on which did stop)

[dwight007fchr]

Spiral/Maz......I ran her again today with a good dose of Seafoam mixed in the jug of gas. Engine runs great and does not smoke at all until after a few minutes when she begins to warm up......then the smoking begins. Same amount of smoke as yesterday, but she was burning Yamalube yesterday and Seafoam today......so, no way to make a logical conclusion until I run straight gas a few times. Once again, when I felt the left side intake pipes, they were actually cool, while the right side intake pipes were getting pretty warm. Is this a sign of some type of issue I need to work on?

[4wred]

I had a similar problem w/aftermarket float needles.Had to change my float height settings a little from the recommended ones to stop the bowls from overfilling.

[dwight007fchr]

Update:

Because Intake Pipe No. 4 was running super cold compared to the others, I am pretty certain it was because Carb No. 4 was dumping too much gas into the cylinder....as a result of a sticking float valve. So I pulled the carbs off again and did see pooling gas still in the carb box when I removed the air filter and upper air box. This is the 3rd time I have taken off these carbs, and want this to be the last time (at least for a month or so). I opened all the carb bowls and increased the gap from the 15mm (factory reccommended) to 21mm:

Float No. 4 prior to increasing gap

21mm Measured from the furthest point of float

I put all the carbs back on and fired her up, with all fingers and toes crossed. She started up and ran great, and all 4 intake pipes were running the same temp, just warm......no cold pipes this time. No gas leaks anyplace.....all good.

She starts up and runs without smoking for a few minutes, and then begins to puff out this whitish smoke from the left side muffler:

Left side is smoking pretty bad

I put a cotton rag up to the muffler for a minute to see if I could capture any oil deposits or some type of clue as to whats going on. No black stains or oil coming out, nor any moisture that I can detect. Is this just a sign that the left side carbs are still running too rich? But at least the intake of No. 4 is no longer cold, but all 4 are the same warm temp.

Also a follow up on the oil level: I put a black mark next to the view window for the oil level, and after running today and yesterday for a total of maybe 20 minutes, the oil level is between 1/8 to 1/4" higher now. I can only guess that this is gas and most of it went in the day it was running and No. 4 intake pipe was super cold (running super rich).

Any suggestions as to what the white smoke is?

Thanks.