Weak fuel pump?

[TTrax]

On 10/25/2021 at 9:54 PM, cimmer said:

When you say the smaller of the two holes, are you aware there are 3 holes between the engine and the throttle blade. The smallest of the holes is the idle Pilot outlet hole for the idle circuit.  This hole is passing a fuel/air mixture and if the black stuff is coming out of there, it could be a bad o-ring that is used in the pilot screw set. The other 2 holes appear to be air holes for vacuum the coasting enrichment valve assemble and piston valve/diaphragms.  You might have to remove the pilot screw and see what shape the o-rings are in. Be aware there is a spring, washer and o-ring in there and they can be hard to remove. You might need to stick a small stiff wire in there to work them all out and there are replacements available for a number of sources.

Hope this helps.

Rick F.

 

You are right, I missed the third hole until I shot some carb cleaner in the mating hole that the pilot jet lines up with from the jet block. 

I went ahead and sent the carbs out to Mike Eykamp in hopes that he will find out what I have been missing. Since I haven't been performing a true carb tear down and rebuild then the issue is probably with my halfassed attemps at focusing on the fuel part of the carb only. 

I did take out the fuel sender and looked into the tank, doesn't look too bad for a +30 year old bike in my opinion. Nothing I can see that would explain the carb getting gummed up after several hundred miles.

I plan on replacing the fuel lines and pump again just to be sure.

[Marcarl]

If that is the inside of the tank, I would be suggesting something maybe.

[videoarizona]

Agreed. Tank needs to be cleaned and sealed. That rust will flake off... Hopeful be caught be filter. What doesn't get caught will cause carb issues.

You have put a lot of effort into the scoot... pleas keep going. Once done, the bike will be a joy for years to come!!

[TTrax]

On 11/21/2021 at 11:04 AM, videoarizona said:

Agreed. Tank needs to be cleaned and sealed. That rust will flake off... Hopeful be caught be filter. What doesn't get caught will cause carb issues.

You have put a lot of effort into the scoot... pleas keep going. Once done, the bike will be a joy for years to come!!

I have to admit, I have thought about selling this thing know than once over the past couple of months. Hopefully I will be able to get this figured out and fixed this time around.

I got my carbs back from Mike and want to make sure everything is okay. I've got a new fuel pump and lines as well as filters.

If I'm going to do the tank, does anyone know what's involved to remove it? I had heard you basically have to split the rear frame off but correct me if this is wrong. I hadn't thought about removing the tank and relining it as my 82 Honda is way worse and I haven't been having any similar issues as what I'm having here. Also, my screens in the tank and fuel filters are perfectly clean with no hint of rust discoloration.

Did these tanks have any sort of liner applied at the factory? This tank has some rust but I don't see any evidence of a liner ever being there in the first place, unless it has dissolved over the years. I would think there would be flakes of debris other than rust in the tank if that were the case but can't see anything so far.

[BlueSky]

The tank on my 85ZN700 is rusty.  When I bought it in 2009 with 1k miles on it, I sloshed the gas around and dumped it to get the rust particles out and put a filter in the line and I've never had a problem as far as I know with rust clogging up the carbs.  They will clog up easily if it sits for a while but with a 700cc engine with 4 carbs the passages are really tiny and it doesn't take much sludge to plug something.  I keep Gumout with PEA in the gas which helps this issue.  My 2 cents.

[Pasta Burner]

On 8/5/2021 at 8:41 AM, videoarizona said:

Glad to see things are coming together! 

Regarding mpgs, the best for economy comes when you let the motor run. IE,  don't bog her down at lower rpms. Especially riding 2 up. Staying in a lower gear, running 3k to 4k rpm, will give you better mpgs than shifting up. Seriously. Experiment. 

Change oil regularly, change plugs yearly and let her run!

Change plugs yearly? How often on wires?  I’ve been going through my own woes and last I rode her a month ago things were great.  I’ve been wanting to get out just haven’t.

[TTrax]

18 hours ago, Pasta Burner said:

Change plugs yearly? How often on wires?  I’ve been going through my own woes and last I rode her a month ago things were great.  I’ve been wanting to get out just haven’t.

I have the Ignitech box on this with cop's instead of the factory coils and wires. I do have a new set of spark plugs I'm going to be installing soon just in case. Don't think that is the problem but we'll see. Strange how I can blow out the jets and passages and it runs like a dream for awhile then happens again. Filters look as clean as when I installed them. One installed between the tank and pump and the other between the pump and carbs.

Mike said that the carb floats were set to the wrong height, too high. Also said the wrong metering needles were installed. Not sure if that would cause my problems but glad to have it back to the right settings I think.

[saddlebum]

18 hours ago, TTrax said:

I have the Ignitech box on this with cop's instead of the factory coils and wires. I do have a new set of spark plugs I'm going to be installing soon just in case. Don't think that is the problem but we'll see. Strange how I can blow out the jets and passages and it runs like a dream for awhile then happens again. Filters look as clean as when I installed them. One installed between the tank and pump and the other between the pump and carbs.

Mike said that the carb floats were set to the wrong height, too high. Also said the wrong metering needles were installed. Not sure if that would cause my problems but glad to have it back to the right settings I think.

The fuel line between the filter and the carb could be deteriorating on the inside

[videoarizona]

That was my problem on my 1st gen. Constant issues with carbs and running until I replaced that fuel line. 

Plugs at least every two years. Wires last a while unless you live by the ocean. Salt corrosion can occur without being seen inside plug wire connections. 

2gen coils and wires seem to be less of an issue than 1st gens that are separate.

[TTrax]

8 hours ago, saddlebum said:

The fuel line between the filter and the carb could be deteriorating on the inside

I would like to think not since it was brand new Gates hose installed a couple of months ago.

Regardless, I will be changing them again asking with another fuel pump just to be sure. Planning on at least cleaning the tank if not removing it and derusting it before sending fuel to the carbs.

I appreciate everyone's thoughts and suggestions on this and hope to have it back to road tripping this next riding season!

[TTrax]

OK just a quick update, still working on this issue. Slowly but surely. I did notice something strange but maybe of no consequence but figured it would be worth noting.

The first photo I had shared awhile back. It didn't mention anything about it as it looked to me as if someone had applied a lot of sealant quite sloppily between the petcock and the tank. I didn't think more about it until I had dried out the tank with a heater and blew it our with compressed air. The next picture was after blowing out the tank, and the last was after blowing it out specifically in the area of the petcock. What I thought was orange sealant seems to have been rust but of a bright orange color which I haven't commonly come across. Possibly rust in the presence of water? I'm not sure, also not sure if this was causing my problem or not. Seems like rust would have stained the fuel filters and the fuel bowls of the carbs but I can't say I know for sure. The filters and bowl are clean for the most part.

For now there are no loose rust particles in the tank. I have considered removing the tank but not sure how much it would take to get it out. Looks like it would be a lot of work but might be worth it in the long run. I might see if there is anyone local that would perform a rust removal and nickel coat a tank if possible. I have heard horror stories of people using a tank liner and having it flake off and plug up fuel filters, so I am hesitant to do it unless it is absolutely necessary.

[TTrax]

Just a quick update... decided to go ahead and drag myself out to the garage today and decide how I wanted to proceed. After much looking at the bike and trying to see how much work it was going to take to get the tank out, I started taking it apart in earnest. It wasn't as bad as I thought it was going to be. I took the luggage cases off the bike, took out the air system, and unplugged any wiring harness connectors I needed to so I could get the frame off the back of the bike. I did find the top left frame bolt was missing so that was concerning for sure. Now just to see if I have someone relatively local that cleans out tanks and treats them, or decide if I want to try to do this on my own. Pardon the mess in the garage, I didn't get it properly cleaned out and took these photos before putting up my tools that were strewn about the work area, along with leaves that had blown in yesterday when loading up some stuff.

[Marcarl]

Yep! You got some work ahead of ya. Don't think that you'll be bored in the next while. Hope it works out well and you enjoy doing it.

[saddlebum]

What mess? Looks normal to me

[TTrax]

OK, it's been awhile since I had updated my progress... mostly because there hasn't been much progress.

I did finally do some research into cleaning the rust out of the fuel tank. I had bought a tank liner kit (Kreem), but after reading a lot of negative reviews, I decided I would forgo doing it for now.

I finally decided to go with muriatic acid. After using a gallon undiluted, I made sure to agitate the tank around off and on for about 2 hours. Afterwards I neutralized and rinsed with water and baking soda. After I got most of the water out of the tank, I poured some alcohol in the tank and drained it too so I could get most all of the water out as possible. That was followed up with a leaf blower in the opening for the fuel sender for about 10 minutes. Finally, I followed up with a good coating of WD-40 and drained the excess out.

Hopefully this will last for awhile, now to start getting it put back together again. The weather here is already nice and been driving me nuts listening to everyone driving around on their bikes. At least I still have the trusty old CB750 to ride around on but its just not the same. Hopefully this does the trick, my wife has already said if it doesn't its probably time to get rid of the Venture. 

I attached some before and after pictures, so far it looks like it did a decent job.

[Marcarl]

Looks clean enough, just make sure you don't get any water in there and fill up each time you fuel. As well as leaving a full tank when it sits.

 

[BlueSky]

Yeah, the tank looks good after cleaning!  Good Job!

[TTrax]

Well I just got back from a ride after syncing the carbs, runs great so far. I will need to put the bodywork back on, Only time will tell if it is really fixed. Usually it runs great for a few hundred miles after taking the carbs apart and cleaning them. I will try to provide an update if I get over 500 miles with no issues. Really hoping for a good outcome because I am tired of tearing this thing apart.

The only issues I can think of that might have been happening is the sealant I used to install the fitting on the fuel pump and the previous owners use of orange RTV to seal the petcock to the tank. When I took the old pump apart for inspection, I removed the fitting and some of the sealant I had used broke off in a piece. I sprayed some carb cleaner with acetone on it and it dissolved in a matter of seconds. Also, when removing the orange RTV on the petcock, it was difficult to remove. I sprayed some of the same carb cleaner on the RTV and while it didn't dissolve immediately, it sure let go of the metal pretty quick. Hoping this is what was causing the issue because I have eliminated both of those sources now.

Thanks again for all the suggestions and encouragement so far. Hopefully this will be the end of the problems but I will let you all know either way.

[Marcarl]

Let's hope it works out for you.

[TTrax]

So far, nothing new to report. I had tried to take it out for some significant riding this weekend but the weather hasn't been cooperating since. I drove about 35 miles on Friday and a little over 60 miles on Sunday. My wife got cold during the ride so we turned around and came back. I have been obsessing over any little irregularity and trying to determine if the engine is running worse or the same as it was when I put it all back together again. So far the engine running hasn't changed since I put the carbs back on, but I don't think I have enough mileage under my belt to start to relax yet. The weather this weekend is supposed to be better so will be putting some more miles on it at this time.

I'm trying to mentally prepare for the possibility of the issue coming back, but I can't really think of much else that could cause the problem. The tank has been acid washed and the fuel system between the tank and carbs has been completely replaced (new fuel lines, new fuel pump, filter before and after the pump).

One thing I am checking for is other possible places that fuel interfaces with the carbs other than the obvious places such as the fuel jets and enrichment circuit. I am looking at the service manual diagram of the carbs but don't see where the fuel from the enrichment circuit is released into the intake. Does it go to the pilot jet hole in the carb body or some other place? Also am wondering if it is possible fuel can get into the area where the adjustment screw for the air adjustment is?

Hopefully I am just being overly cautious and the problem won't come back. I am just trying to get a plan going in case it does. I don't think that the air adjustment has ever been touched as the plugs are still in place.

Just for reference, I am attaching a short video of it running. Idle is a little lumpy but has been that way for as long as I have owned the bike. Not sure if this is common or not, but as long as it doesn't change drastically I am fine with it.

[Marcarl]

Sounds good from here.

[cimmer]

I would say just go out and ride it and enjoy..  get about 1,000 miles on it and then maybe bring it back and check the pilot screws for the idle mixture and then resync the carbs if needed.  One thing I do is when I fill my gas tank, I usually add some seafoam to the gas to help keep it fresh and to help keep the fuel system clean.  About the only time I dont add seafoam is when I am going to be riding all day and filling the tank a few times, then I usually wait till the last refuel before adding it again.

Rick F.

[TTrax]

Well, I have gotten nearly 1000 miles on it with no real issues, hoping that it is resolved.

I did notice yesterday, I had a couple of hiccups when driving in town at slow speeds and the engine was warm enough to kick the cooling fan on. First time was when I was riding at lunch in a small town near work. Just one miss or sputter as I was accelerating at low engine speeds. I drove on back to the town I work in which was about  5 miles away. I got back down to driving slowly through town and it did it again, same situation. I cycled the emergency stop switch to make sure it wasn't getting flaky.

That evening, I drove back home and was on higher speed roads for the most part. I did end up driving slowly while in town, the high was somewhere between 98 and 100 degrees. It never hiccupped at all during this trip. When I got to the house, I went ahead and took off the left side cover to check out my fuel filters.

The one between the tank and pump was half full, but this seems to be normal for it. I could see fuel flowing from one side to the other. The one I have installed between the tank and the carbs was different, I was seeing on average about 1 or 2 bubbles every couple of seconds or so. Wondering if when the outside temps are very high and engine is pretty warm if I am getting the beginnings of vapor lock. Never seems to happen when driving at highway speeds. 

My wife and I are going to take it for a fairly long ride tomorrow, so we will see what happens. Really hoping the same problem I have been having isn't coming back. So far this feels totally different, and it seems I remember it happening before I had all these carb problems this last year. It always seems to happen on hot days and at higher engine temperatures. 

I guess another possibility is that one of the pick up coils for the ignition is getting flaky but I guess to test that theory I would need to replicate the environment in which the problem seems to happen and check resistances then. When cool, it seems that they resistance is right on what the factory spec is.

I will update if something else changes or the problem comes back. 

[cimmer]

Just curious, does your bike have the plastic shields that sit on top of the valve covers?  There are use to direct the air flowing thru the radiator out the back of the engine or thru the vents in the side panels. They help to keep some of the hot air away from the carbs., 

Just wondering if you had those still in place.

Enjoy the riding and the bike.

Rick F.

[TTrax]

Yes, the plastic shields are still in place. The coil-over-plugs takes up a lot more space that the wires or caps on the plugs would have but are still present.

This morning we decided to take a drive to Neosho Falls, which is a little ways away. There is an old abandoned school house that my wife really likes and we decided to head out on the bike. Right as we were taking off in town, I had an instance of one hiccup after going over some rail road tracks. We ended up having to go back to the house for unforeseen reasons. While the bike was there, I took the connectors apart for the TCI and worked them back and forth several times. I also cycled the emergency stop switch about 5-10 times back and forth. We took off again for a 250-300 mile ride and it never hiccupped again the whole time. 

I am thinking it was either the TCI connectors, the stop switch, or the fuel I was using. There are a couple of gas stations in town with lower cost fuel but now I am wondering if they are peddling E15 and not E10 like most stations are. When the hiccup happened this morning, the bike was relatively cool so I am thinking that the problem was electrical in nature. Still I don't think I will getting fuel from that station anymore as an extra precaution. 

I guess I will have to keep riding to see if the problem comes back or not. I am hoping it has been fixed, as of now I have put about 1,300 miles on it since putting it back together this year. Hopefully things will keep looking up but will update one way or another. Hoping you all are having a great weekend! Here are a few pictures I took...