for the last 3 months I am trying fix my carburetors and it looks like I stuck..... :flag_of_truce:
It started with small leak from one of tubes from one of the carburetor. Just few drops after ride.
So I decided to buy new float needles and seats made by Tourmax.
I replaced them but during ride I noticed popping from exhaust during deceleration.
I checked vent tubes and 2 of them were moist.
After third time with carburetors on bench, when everything seemed perfect, I decided to get new float valves from Randy.
Since then I tested all possible combinations: new / old seats with old or new valves.....
The results is always this same:
When i put them upside down and connect pressure to them and set it to 1 Bar they will hold it for few hours.
From syringe attached to carburetors over night will go around 50ml of petrol until the level will reach half of the length of the clear tube. then it stops.
It looks like this extra petrol goes to all 4 carburetors because after adding more and more petrol finally all of them will start leaking
I have no idea what to do..... or maybe 50ml per night in such cold weather is not that bad.....
Tank full of fuel, with the bike is shut off, is your fuel pump tight? ........or does it dribble gas?
Where's Noel?
Fuel pump is OK. Carbs wont be flooded when engine is off.
I have 3 different sets of new float valves and set of new valve seats and old cleaned very well with toothpaste.
And all my bench tests are this same...... petrol from syringe slowly flowing to carburetors......
To me it sounds like float height is wrong letting to much fuel into bowls.Float height should be 21.3 - 23.3 mm from gasket mating surface if i remember right. Measure with the carbs tilted so that
floats barely touch the valve needle spring
Here are some good videos explaining :
https://www.youtube.com/watch?v=Bxx5Iw1xoVw (https://www.youtube.com/watch?v=Bxx5Iw1xoVw)
https://www.youtube.com/watch?v=4iYiCa3Nmqg (https://www.youtube.com/watch?v=4iYiCa3Nmqg)
If you use a clear tube to measure fuel level it should be like in the picture here:
Float level is checked..... many times
I have set float level on 23mm. And I measure as it is explained in file section.
I started thinking about buying a new set of valve seats..... just in case
If you removed the old carb bowl gaskets and then reused them they often shrink, then they can rub on the float making it sticky.
I made a tread about that here : http://www.fjowners.com/index.php?topic=18788.0 (http://www.fjowners.com/index.php?topic=18788.0)
I recommend using new gaskets. You can make the gaskets original shape again by bowling them for a few minutes in water but best is to buy new.
Do you have the correct size seats for the FJ fuel pumpers?
(The gravity flow seats are larger and they will leak when subjected to the low pressure of the fuel pump)
http://www.fjowners.com/index.php?topic=9836.0 (http://www.fjowners.com/index.php?topic=9836.0)
Quote from: Pat Conlon on February 11, 2021, 10:00:32 AM
Tank full of fuel, with the bike is shut off, is your fuel pump tight? ........or does it dribble gas?
Where's Noel?
Pat, I sent him a PM a week ago with details and photos of the solenoid, float tang divots, fuel pump, float levels etc. and a lot of other info relevant to his problem.
Noel
Quote from: ribbert on February 11, 2021, 04:07:14 PM
Quote from: Pat Conlon on February 11, 2021, 10:00:32 AM
Tank full of fuel, with the bike is shut off, is your fuel pump tight? ........or does it dribble gas?
Where's Noel?
Pat, I sent him a PM a week ago with details and photos of the solenoid, float tang divots, fuel pump, float levels etc. and a lot of other info relevant to his problem.
Noel
Cool beans...
Quote from: MOTOMYSZOR on February 11, 2021, 07:59:04 AM
for the last 3 months I am trying fix my carburetors and it looks like I stuck..... :flag_of_truce:
May or may not help, but I used to fill my tank up before I made it home, so next ride, I was ready to go.
I was "overfilling" it, I never would have guessed, but just stopping the fill lower than I had been doing took care of my problem.
Also, there is a valve in the cap, a pressure valve. You might hear it singing from time to time.
I removed that as well.
I need to be able to confirm a couple of things.
The fuel is leaking from the bowl vent tubes?
There are only two of those and they are the larger hoses that go up to the white plastic tees between carbs 1/2 & 3/4.
Or are you seeing fuel in the four smaller cold weather fuel enrichment (choke) hoses?
There are four of these hoses and the attach to each individual carb.
Popping from the exhaust could indicate a lean condition. If the carbs are popping back through the carbs, the carb bowls will be come pressurized and push fuel out of the four smaller enrichment (choke) hoses.
I see you purchased new float needles only and not the seats. As Pat mentioned, did you get the correct size seats? If you have gravity feed they are marked 2.3. The F/P seats you require are marked 1.5. Secondly, you have to reset the float level from the new to old needles.
The carb bodies where the needle seats insert, how's the surface where the o-ring sits. Is there any corrosion allow fuel to bypass the o-rings into the bowls?
Floats, have you checked to make sure they don't have don't a small wear dimple at the contact point of the needle. That can cause the float to not travel freely and could be a source of fuel leakage.
Sorry, I am not sure if some of this is redundant as Noel has already sent advice via PM and is not visible to the rest of the forum.
Randy - RPM
I have checked everything today.
Seats are proper size, gasket has enough clearance, fuel level is perfect (23mm)
Petrol is leaking from the smaller hoses. it is not dripping, just a drop of fuel on end of 2 or 3 tubes.
During one of the test rides exhaust turned in to a cannon.... when I stooped petrol was dripping from one of the tubes so I am sure that is from excess of petrol.
For a last month I just conduct bench tests.
Today I checked float valves under microscope.
On left side old one. Right side is the new one. The difference is visible.... maybe that is the problem :dash1: :dash1: :dash1:
What are you seeing in the microscope that you believe is causing the issue?
I'm still not convinced you have a float/needle seat issue. Since fuel is not "running" out that indicates the floats are not bypassing. You stated the fuel pump didn't leak, so you maybe chasing the wrong issue.
If the fuel enrichment dip tubes are not venting, then the could be siphoning fuel from the bowls. The key will be determining what the fuel level on the bowl is doing, rising, falling or maintaining.
Did you install the oversize o-rings around the needle seats and did you "polish" the bore?
Still many questions to determine what your actual problem is.
Randy - RPM
I think that I found the problem: following Randy's "checklist" I discovered wear dimples on each float.... I filed them down and instant result: over night just 20ml of petrol flown down to carburetors.
So big thanks Randy for Your checklist.
Now the question is: 20ml per night is acceptable or should I buy new floats?
Quote from: MOTOMYSZOR on February 14, 2021, 01:59:46 PM
.....following Randy's "checklist" I discovered wear dimples on each float.... So big thanks Randy for Your checklist.
Did they look like this...
(https://live.staticflickr.com/928/43046832114_dbe430bfb4_c.jpg)
Noel
Quote from: racerrad8 on February 11, 2021, 09:47:51 PM
.... Noel has already sent advice via PM and is not visible to the rest of the forum.
Randy - RPM
Haha, maybe on this occasion I should have, it included the photo below and detailed instructions, amongst other things.
Randy, barely a week goes by here without someone publicly acknowledging the advice you give via PM, email and even the phone, none of that's visible to the forum!
There's a funny story about that. A few years back I got a PM from a member in the US, Randy had rung him and talked him through whatever the problem was he'd posted about. He admitted, by way of explaining what brought him to me, that he was so in awe at finding himself actually talking to Randy that he was rattled and remembered virtually nothing he said. It was as if he'd picked the phone and found God on the other end. He was amazed that Randy would spend his time ringing
him and couldn't bring himself to impose even more on it by asking again, so he contacted me and asked if
I could explain it to him.
I'm sure the slightly offensive circumstances and the the irony of suggesting Randy's time was more valuable than mine, but wanting my help, was lost on him.
Noel
Quote from: ribbert on February 15, 2021, 07:26:28 AM
Quote from: MOTOMYSZOR on February 14, 2021, 01:59:46 PM
.....following Randy's "checklist" I discovered wear dimples on each float.... So big thanks Randy for Your checklist.
Did they look like this...
(https://live.staticflickr.com/928/43046832114_dbe430bfb4_c.jpg)
Noel
This same pattern but in my case wear was less severe. I used my blunt file and sandpaper 2500.
It looks like finally I am ready for test run :lol: :lol: :lol:
Thank You all for help.
Quote from: MOTOMYSZOR on February 14, 2021, 01:59:46 PM
Now the question is: 20ml per night is acceptable or should I buy new floats?
Glad you found an issue and it helped with the leakage, but now to answer your question...
No, 20ml leakage overnight is not acceptable. Where is that fuel going?
Filling the bowls
Leaking out of the enrichment hoses
Weeping up into the carb throats
You need to find out where the fuel is leaking to ensure you don't accidentally hydraulic a cylinder.
Randy - RPM
Prepare to be surprised...... :wacko3:
I noticed that petrol level in my auxiliary tank lowered down after all this tests.... more than it should.... So I marked petrol level and discovered that after every test I have to add 50-60 ml to keep it on this same level.
So last few days I spent looking for a leak.... nothing. Carburetors body was bone dry...
I discovered that silicon hose going from syringe to carburetors is always covered in some kind of condensation, like water, but it was to much and I decided to change it for other hose - thicker one.
After that change from syringe disappeared less than 2 ml..... it looks like petrol was evaporating thru this silicone tube walls in rate 40-60 ml per day.
It took me 2 months to discover that main problem was f.... silicone tube...... :ireful: :ireful: :ireful:
Well now, I'll be a monkey's uncle.... (not you Mark)
Quote from: Pat Conlon on February 18, 2021, 07:12:51 PM
Well now, I'll be a monkey's uncle.... (not you Mark)
(https://media.gettyimages.com/photos/chimpanzee-picture-id185266277?s=2048x2048)
I know how it sounds...... so I conducted small test.
as on photos: after 16 hours from syringe disappeared around 50 ml ......
Silicone tube is all covered in petrol.....
If you did that test in room temperature and had no lid on top of the syringe i think 99% of the fuel just evaporated into air.
Quote from: Old Rider on February 19, 2021, 04:10:10 AM
If you did that test in room temperature and had no lid on top of the syringe I think 99% of the fuel just evaporated into air.
Just finished another test. This same condition: my garden shed with temperatures 5C-8C with no sun.... Only this night was very windy so it added to evaporation rate.
From blanked syringe evaporated around 5-6ml after 12 hours and little bit more than 10 ml after 24h. So in 16 hours it was maybe 8ml.
Quote from: MOTOMYSZOR on February 18, 2021, 06:46:21 AMI discovered that silicon hose going from syringe to carburetors...
Never use any type of silicone with gasoline. This includes RTV silicone.
Bill
Quote from: FJmonkey on February 18, 2021, 11:49:17 PM
Quote from: Pat Conlon on February 18, 2021, 07:12:51 PM
Well now, I'll be a monkey's uncle.... (not you Mark)
(https://media.gettyimages.com/photos/chimpanzee-picture-id185266277?s=2048x2048)
How long have you been waiting for that one?!
Quote from: fj1289 on February 20, 2021, 07:31:06 PM
How long have you been waiting for that one?!
I did not see that one coming, I had to search for it...