[JordanMix]

what is the recommended fuel flow in ML per minuet out of the petcock? I am having some problems that i have traced back to fuel supply and i think it may be that my carb is not getting enough fuel from the tank. I measured about 6 times and each time i am getting about 200-215 ML per minuet from the petcock with the fuel line running into a measuring vessel. I have removed the petcock, disassembled it and removed any gunk with no change in flow.

I have seen some post on other boards that suggest 250 ML ever 30 seconds, if this is the case i am way off.

I think i have a triumph petcock in the garage, maybe that will fit to see if i have some better flow. Any thoughts or suggesting are much appreciated. just want to make sure i am not chasing this in the wrong direction.

[mrunderhill1975a]

I just checked the Snidal manual and it says:

"Placing the open end of the line in a clear glass jar, turn the tap back on, and observe the rate of fuel flow. It should fill up a 250ml (8 oz) jar in 30 seconds or less. "

Generally speaking, Pete seems to know what he is talking about.

[mrunderhill1975a]

It just occured to me that you may want to check the vent hole in the gas cap, if it is partially or completely clogged, the fuel flow would be restricted.

[JordanMix]

thanks for the replies. I did think about the cap causing the problem so i took the cap completely off and ran a test twice with the same results. looks like a new petcock is necessary. Strange that is just happened out of no where and even after disassembling the unit and cleaning it nothing changes.

[mtrude]

Hello , for what its worth I had a similiar problem and in cleaning the petcock i found it needed the tube for the run position reamed or cleaned as the tanked contained more dirt and debris than I had ever seen. Also the filter in the petcock seems suceptible to damage also. Have fun, mtrude

[t120rbullet]

Are you having fuel starvation problems?
Did you clean BOTH the fuel strainers?
The one inside of the tank and the one underneath the petcock?
CJ

[JordanMix]

yes i have a sudden unset of fuel starvation problems. My bike is running lean and it is having idling problems wants to stall out at low speeds. i adjusted the carb for 2 days with no changes. After measuring the fuel flow i am confident this is the problem.

I have cleaned both screens. I removed the lower unit and cleaned it out, it barely had anything. Once i removed the petcock from the tank i removed the mesh screen on the inside filter and blew out everything. What is confusing to me is that the flow is the same both on the main and reserve. You would think that if one was clogged the other would be open. I am going to try to blow out of fuel line tonight and see if that helps. I also have a Triumph petcock that should fit i will see how that works.

[cyrusb]

But you do have flow, although less than what Dr Snides recomends. I would think it is still more than your bullet can use at any throttle setting. You just need enough to keep your float bowl full. Start looking elsewhere.

[mtrude]

Hello , Would the amount of fuel in the tank effect the flow rate?  have fun, mtrude

[JordanMix]

im not sure if it would or not. I have about 2 gallons in their now and i have run with much less so i doubt that is the cause.

[cyrusb]

So if the screens are clean and fuel is running out of the petcock , the next place to look is downstream at the carb.

[JordanMix]

already did work on the carb. i traced it back to fuel. I am not even getting half of the amount per minuet that is recommended in Pete Snidals manual. i am getting just over 200 ML per minuet, he recommends 250ML in 30 seconds.

[cyrusb]

I'm having a hard time believing that  250ml a minute is not enough to run that engine.  Its a 70 mpg motor, not a 454. All you need is a full float bowl, and it seems to me that rate will do that. Why shouldn't it? If everything is clean, then the rate your seeing is the rate its allways had and ran ok with. no?

[baird4444]

yes i have a sudden unset of fuel starvation problems. My bike is running lean and it is having idling problems wants to stall out at low speeds. i adjusted the carb for 2 days with no changes. After measuring the fuel flow i am confident this is the problem.
I have cleaned both screens. I removed the lower unit and cleaned it out, it barely had anything. Once i removed the petcock from the tank i removed the mesh screen on the inside filter and blew out everything. What is confusing to me is that the flow is the same both on the main and reserve. You would think that if one was clogged the other would be open. I am going to try to blow out of fuel line tonight and see if that helps. I also have a Triumph petcock that should fit i will see how that works.

First off; I think you'll be surprised how simple the reserve side is. The inlet for "ON" is just a littlle taller in the tank than the reserve inlet. When you flip to reserve you are only switching to a lower inlet in the tank. If you werre to leave it on reserve you would just run out of gas at a lower level...    It's a real head slapper when you remove the tap from the tank and see it.
    ok, you've blown out the screens in the tap...   
same problem...
gas cap vent is clear...
Have you pulled the carb and blown out every hole and orifice you can find? Blow them from both directions...   inspect needle; re-set float; and I'm betting that BOB is gonna be your uncle.
                - Mike

[JordanMix]

I completely disassembled the petcock and drilled out the holes a bit more and I’m still only getting about 200 ML a minuet straight from the petcock and also through the carb with the bottom float bowl hexnut cap removed.

I know most people on here have said that 200 ML should be more than enough but there seems to be no agreed upon number. I have read quotes from Peter Snidal that says 250 ML every 30 seconds and then in his manual it says 1 liter a minuet (which seems way to much to me). I kinda just gave up on the flow as it seems adequate for the bullet and I have cleaned everything out so I am assuming it was always flowing at 200 ML.

I have the same jets in that I always did and I have blown each hole out with air and carb cleaner probably 5 times each. I started to play around with the float level last night but I didn’t make any progress.

Can someone answer a few questions on float height for me:

I have seen 15-17 MM listed as a float height as well as 25-28 MM. Which is correct? Also, where do you measure from. I would assume that you are going from the gasket surface to the top center of each float chamber? There are also some variables… do you let the weight of the float rest onto the needle assembly and measure it that way or do you elevate the float assembly so that the tang just touches the float needle and measure it that way?

When making adjustments do you bend the actual float chambers up and down or do you bend the angle of the tang that suppresses the needle assembly?

Here is a big one and may be obvious to some but I don’t know the answer. If you are looking at the carb with it mounted to the bike with the float bowl removed would raising or lowering the floats lean out the mixture?

I don’t know if all of this is common knowledge but it really should be included in the Workshop manual and Peter Snidals manual… it is not in the editions I have.