fuel flow

[jjz28]

How much fuel should flow from the petcock? What kind of stream should it have? I got rid of my octi and have been running on reserve because my "on" doesnt flow fuel. Should i run the prime side instead of reserve? Im not sure i am getting enough fuel flow.

[BA80]

You need to remove and disassemble those petcocks if your getting no flow when in the on position. They are probably full of gunk.

The petcocks are pretty simple and straight forward.

You will have NO reserve if you run them in prime or reserve position. Not a good idea.

[fredintoon]

How much fuel should flow from the petcock? What kind of stream should it have? I got rid of my octi and have been running on reserve because my "on" doesnt flow fuel. Should i run the prime side instead of reserve? Im not sure i am getting enough fuel flow.

Hi JJ,
yeah, tear the taps down because something ain't right.
BTW, you shoulda capped off the PRIME spigots when you ditched the octopus. To run on PRIME you will have to put a fuel hose back on the PRIME spigot and Tee it into the ON + RES fuel hose both sides.
As has been posted, running off PRIME, same as running off RES, will run you completely out of fuel if you don't carefully watch for the red "low fuel" light to come on. If the bulb ain't blown.

[petejw]

jat,
have u made sure ur running a full/ near full tank of fuel
to check out the petcocks?

[jjz28]

Thanks guys, i have tried with full tank of fuel, the thing is, I just dont know if i am getting enough fuel to feed the carbs good enough in the high rpms. I have been having a kinda low in stumble and then it rockets off and then a higher end stumble at wot when i get to the higher rpms (tach dont work but I know its not over redline). I am not synched though, just eyeball benchsynced. The thing is if im riding slow around town and then open it up in second or third it will seem to run out strong in the high rpms the first time but then it seems like I dont have enough gas to do it again, like maybe the fuel builds up running slow and fills the bowls and it will pull good and then after one good pull it misses at high rpms the next time. It runs good and isnt a very big stumble/miss at all and it isnt like i am getting no fuel like I forgot to turn on my petcocks, it not that bad at all just a little flutter up high. Maybe its cause I aint sycned.

[petejw]

are u running the stock main and pilot jets?
also are u running the stock float setings,

are both the petcocks flowing at the same rate
or is there definately one flowing faster than the other,
if u have the fuel lines 't'd together, then 1 petcock
working correctly would feed enuff fuel for the carbs.

[jjz28]

no i dont have them t'd together, i have the running staight down to the carb. I had to cut the gas line really short so it would not kink. I do the on flows better than the other. Everything is stock on the bike except for some harley like exhaust. I just realized that 2 carbs are fed by each side, I was thinking all 4 were hooked together with t's. So if one petcock is flowing slower, those 2 carbs would get less gas. I am going to try to T i today and see what happens. Thanks a lot.

[DGXSER]

You could also try a throttle chop test after your first high RPM run. It sounds like perhaps your running rich in on the mains. Starting to foul out the plugs at hgih RPM, then running on the pilot circuit it clears them up. If you do nto give the pilot circuit time to clen them up, the mains start fouling them out.

Just another thought on it.

[jjz28]

I just checked the fuel flow and the flow the same amount. I put new plugs in it yesterday and the look great. I will try the chop today. I am going to try and find someone with the gauges to synch it.

[TADracer]

But to answer your question, last time I measured it was something like 8 oz. per minute each as I recall. I did not write it down. Still, if plumbed with a crossover then one cock will run the motor at WOT.

[jjz28]

I think mine would be way more than that. I had about 1 1/2 inch in the bottom on a jar in 5 seconds. Counting 1 one thousand 2 one thousand, so I am sure in a minute it would be more than 8 oz. That is just running it out of the petcock into the jar.

[GTXS1100]

Float Hight?

I would check to make sure your floats are adjusted right before i synced them. I had simmilar issues with my bike. I found that the floats were smashed down causing my bike to flood the engine. I got that fixed and had it synced and she runs great. Thats just my 2 cents and something to try. Im not sure on the specs but i think i set my float hight to an inch. Hope this helps.

[jjz28]

I should have mentioned that mine are set and 1" too. Thanks guys.

[motoman]

I should have mentioned that mine are set and 1" too. Thanks guys.

If those carbs match the yr. scoot you have, those float levels ARE too high, and will cause what U have goin' on.

[EricHa]

78-79 carb floats are to be set between 24.7mm and 26.7mm. 25.4mm is 1", and right in the middle of spec. Measurement is from the gasket surface to top of float, with gasket removed.