CJ360 Bowl overflow leaking

[shocwav3]

as title states, just the right carb. What could be causing this? I have searched and already tested the folowing and found them to be good

Reset float height as per manual (2 times)
Ensured floats actually float (no holes)
I have soldered the overflow tubing inside the bowl becuase they were previously leaking, they do not leak now.
I can blow through the fuel inlet, when I depress the float ( or raise it assuming it is on the bike) it will stop the flow into the bowl
I can hear the floats moving as I rotate the carbs, so they are not binding.

I am at the point in my build where I should be tunning and chasing down the little stuff but I really need to get this worked out before I press with the little stuff.


Bike starts on first kick and idles pretty decent (as decent as I can expect with baseline settings)
Bike is running the stock carb with a rebuilt carb kit and 112 secondaries.
Compression is 140-142 left and right respectivley.
I have no filters on right now
I am running a modified exhaust with just baffles.

Please let me know if any more info will help get this sorted out.

Any info is welcome.

 

[boykinjw]

have you taken the bowl off and filled it up with gas while the bowl is off the bike? I know you soldered them but there could be a hairline crack.

 

[Sonreir]

Might be small scratches in the float needle and/or needle seat. Clean the float needles off with a microfiber cloth and denatured alcohol. The needle seats can be cleaned up using a q-tip, power drill, and a bit of tooth paste. Clean the paste off when finished, of course.

 

[crazypj]

You are setting float height with carbs tilted and not completely inverted?
the 'O' rings on shut off valves are good?
try some weed wacker fuel line over stand tubes, pushed all the way down it will seal (for a while)

 

[shocwav3]

Thanks for the reply guys.

Boykin-I verified the solder job by filling the bowl and letting it sit for a few hours. They tested good.
PJ- I am setting the carbs with a 45ish degree tilt, just enough to touch the spring loaded pin on the shut off valve without depressing it.
Also I put new o-rings in before I put them back together.
Sonreir- I will look at both for scratches/damage. None that I can recall though.

Is it enough to assume that my float needle and seat are working properly by my above mentioned test (blowing air into the fuel inlet and operating the floats, when depressed it sealed and when lifted off the needle air flowed freely) or is there a more acurate way of testing this?

I also bench tested the carb by hooking up fuel to it and letting a small bottle filled with fuel sit above the carbs for a few minutes. I was getting fuel in the bowls but no leaking, its only when it is actually running on the motor that I get the leak. I can turn fuel on before starting and let it sit indeffinitly without it leaking, but once I run the bike it begins after a minute or two then will continue even after shutdown.

 

[crazypj]

Sounds like your doing everything right.
What height did you set float level?
I use 19~19.5mm minimum
I oil the 'o' rings when sliding shut off valves into carb body
The float bowls are venting properly?
You didn't put tubes on the brass vent did you?
(if you did you blocked vents)
sounds like heat soak in carbs pressurising float chambers?

 

[shocwav3]

floats are set at .730 tho
I am going to pull the valve seats and replace the o-rings (any chance you know what size they are?) I will oil them on the re-install
I assume they are venting properly (how can I check?, is the overflow acting as the vent?)
I am using 1/8 tubing on the outside of the overflow to run the fuel past the motor and out under the frame(I am doing this on both sides but the right is the one acting up) but I assume you are refering to the inside of the bowl? In that case no.

This sounds like it might be my culprit---->sounds like heat soak in carbs pressurising float chambers?
How can I test, prevent it? The right side exhaust pipe (side that I am getting the overflowing carb) heats up twice as fast as the left, dont know if that points to anything?

I am sorry I am asking so many questions, I am just trying to learn as much as I can about CV in general and troubleshooting. I hate not knowing everything about something I own.

Thanks again for the help and quick response.

 

[crazypj]

19mm is about 3/4"
0.730" is going to be slightly low so fuel will be high in float bowl.
I would go to 0.750"~0.770"
The range (+/- 1mm) is to compensate for running or altitude adjustments, the only allowable adjustment under EPA regs
You should always start in the middle

 

[shocwav3]

19mm is about 3/4"
0.730" is going to be slightly low so fuel will be high in float bowl.
I would go to 0.750"~0.770"
The range (+/- 1mm) is to compensate for running or altitude adjustments, the only allowable adjustment under EPA regs
You should always start in the middle

I will set the floats lower, and re check everything. I will report back with what I have.

 

[crazypj]

Set floats higher to lower fuel level
Can you post a pic?

 

[shocwav3]

By lower I mean farther away from the carb body allowing less fuel to fill up the bowl before closing it off. Am I thinking the wrong way?

In this pic I should be moving it towards the camera to lower the level, correct

 

[crazypj]

Yep, your thinking right, edge of float further away from gasket face
Is the blanking plug missing on right carb? (I think we already went through that?)

 

[shocwav3]

PJ-

Sorry old pic, I turned a plug to press up to the inner shoulder as per your suggestion and sealed it in.

Alright, I raised the floats to .780, also I swapped the floats and needle to see if it will swap the problem (rule out the float or needle being faulty)

I re inspected my intake boots with a flash light an saw some gaps between the head and gasket so I re-seated them as well. ( I made some copper gaskets from .080 thou that I am using)

I will get it all bolted up and see what I have got tonight or first thing in the morning.

 

[IanOberholtzer]

Having a really similar problem right now, left carb overflows with fuel, but not then running ( wouldnt know atm ), raised my float height from 19/5 all the way to 25 and it does not leak, but its way off,


hrmm

 

[shocwav3]

Having a really similar problem right now, left carb overflows with fuel, but not then running ( wouldnt know atm ), raised my float height from 19/5 all the way to 25 and it does not leak, but its way off,


hrmm

I would be suprised if you are getting any fuel in the bowl with that high of an adjustment?

 

[crazypj]

If you need more than 21mm, there is dirt or damage to shut off valves causing leak.

 

[shocwav3]

Set floats at .780 and I am no longer leaking fuel, the left carb seems a little dry compared to the right but I think some fine tunning can solve that!

 

[IanOberholtzer]

I replaced the shut off valves in on both sides, still leaking... any other suggestions? would it be my needle at that height?


This is a big riddle to me, hrmmm

 

[crazypj]

Ian,
you may have damaged the 'o' rings?
I know you have inline filters so dirt shouldn't be a problem
You did oil 'o' rings when you fitted new shut off valves?
(I don't remember, I was pretty messed up from surgery when you came round, few weeks are a bit of a blur)

 

[Sonreir]

Crack in the overflow tube, perhaps?