Did you clean the fuel tank screen? Rust in the regulator ? There is no steel in the fuel system except for the injector caps. Are you using the huge fram fuel filters or the junk stock ones. Did you gut all 4 valves of the quick connects? is the filter full of fuel while its running or does it drain mostly empty in the outside? A cut or torn external oring on the suction side quick connect will cause erratic fuel pressure because itrs pumping air the system with the fuel.
On a side note I know you are focussed on the fuel system but a bad coil will have an issue with running rough ,hard starting and stalling when the engine is warmed up. I had a plugged tank screen cause a similar issue .It would run great for a minute then just die if throttle was applied until it would just idle. it happened out of the blue on a half day ride. I idled it back the last few miles.
Irregular fuel return
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fasternu_674
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- Joined: Wed Mar 10, 2021 10:41 pm
Pretty sure it is the fuel system. I can watch the fuel pressure and performance drop together and it is getting progressively worse.
The fuel tank screen is clean took it out cleaned throughly as well as replaced the pick up line in the tank. I am using a semi small fuel filter. Never had a problem in the past with fuel flow through the filter.
I gutted all 4 fuel fittings so you can see daylight through them all.
All o-rings are new and in good shape.
Fuel filter stays full of fuel 100% of the time. Very few tiny air bubbles ever in the filter.
I cleaned the injector caps throughly and put them in an ultrasonic machine, everything in the system is new other than a used regulator(pulled off one of my cannondales) I do currently have an aftermarket fuel pump on it. Was supposed to be the correct replacement but I am starting to doubt that. It is a Bestest Fuel pump part # BE2000
The fuel tank screen is clean took it out cleaned throughly as well as replaced the pick up line in the tank. I am using a semi small fuel filter. Never had a problem in the past with fuel flow through the filter.
I gutted all 4 fuel fittings so you can see daylight through them all.
All o-rings are new and in good shape.
Fuel filter stays full of fuel 100% of the time. Very few tiny air bubbles ever in the filter.
I cleaned the injector caps throughly and put them in an ultrasonic machine, everything in the system is new other than a used regulator(pulled off one of my cannondales) I do currently have an aftermarket fuel pump on it. Was supposed to be the correct replacement but I am starting to doubt that. It is a Bestest Fuel pump part # BE2000
Check amps being drawn as well during open flow test then check again during a load test with bike idling. If they are a$$ loads higher under load its a dead pump. Walboros usually make a death rattle before they go though. YMMV
If you can do a restriction test check to see how much it flows at 43psi. Should fill a gallon in a minute or so. To do that pop of return line plug it into container open gas cap fire bike let her rip.
walboro 255's have internal screen filters as well dunno about the 190's worth a check though.
If you can do a restriction test check to see how much it flows at 43psi. Should fill a gallon in a minute or so. To do that pop of return line plug it into container open gas cap fire bike let her rip.
walboro 255's have internal screen filters as well dunno about the 190's worth a check though.
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Canniboomer
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- Joined: Wed Mar 10, 2021 10:41 pm
Did you accidentally switch the hoses at the fuel regulator?
...hmmn why mess with a so-called "replacement"?...our pump is very unique, and any aftermarket SUB would just use more power than needed, and they usually scream even worse than the stock pump does (from the same restricted flow of our stock plumbing). The OEM pump delivers PLENTY if you open the flood gates, so to speak, and even a Walbro 190 is a power drain, and generates more heat than the stock pump (about 130 lph and perfect).
Or you could replace the Fuel Pressure Reg insert-pod now anyway, and save your old one for a spare if it does not cure the problem...(in stock). The Fuel Reg can do weird things. I had one machine, with the entire fuelpath opened up -- that would start up and hold near 45psi for nearly one minute at idle, but then the system pressure would magically start to creep up to 85 psi and start glutting the cylinder... can't explain why, but a new pressure pod cured the problem. That same reg pod had been gunky and cleaned, but from the long-stored machine.
The stock fuelpump does have an iron-steel gerotor inside, and it can most definitely rust inside there -- and much more than the plated injector caps might rust....so it's a good idea to use a fuel treatment that controls the moisture.
Once the fuel fittings are gutted, there is no need for an intake screen in the tank.....it's just something else to clog up, and no longer needed to protect any in-line valves (those 6 components you removed from the suction fuelpath already). You can just pluck the inlet screen off next time, and let the fuel filter do the whole job.
Fuel filters?, the genuine OEM Cannondale version is not junk, as it's a 35-micron and well suited for a decent span of use, and it's compact and best for dirtbikes with a coolant overflow bottle and less space.... but it seems all the chinese rook-a-rike filters and the Napa Gold (Wix's) are 12-micron,...so yes a same-looking substitute filter in a 12-micron is not good for very long on a Cannondale....far too many of those are still being distributed to cdalers out there. When in doubt, change it, no matter how it may "appear", and sure you could switch to the jumbo Napa if you are still married to 1/4" lines from the filter to the pump.
I do have a 25-micron Jumbo filter with 5/16" in-out, and higher flowing pump inlets for a 135 or 90-bend angle for 1/4 andn 5/16.. If you have any disconnect above the filter, it's easy to transition to 5/16" from there -- and yes it makes a flow difference, just like opening up the faucet more...
As mentioned, a good flowing filter will usually appear "emptied out" while running, since the fuel is sucking through fast.
But a full filter means 1 of 2 things;...not flowing much at all! and the air pocket creeped upward (your machine?), or 100% fully self-primed with the air pocket sucked down and through the pump, which does not happen on a cDale with the stock fittings(gutted or opened), or with the stock fuelpump inlet.
...hmmn why mess with a so-called "replacement"?...our pump is very unique, and any aftermarket SUB would just use more power than needed, and they usually scream even worse than the stock pump does (from the same restricted flow of our stock plumbing). The OEM pump delivers PLENTY if you open the flood gates, so to speak, and even a Walbro 190 is a power drain, and generates more heat than the stock pump (about 130 lph and perfect).
Or you could replace the Fuel Pressure Reg insert-pod now anyway, and save your old one for a spare if it does not cure the problem...(in stock). The Fuel Reg can do weird things. I had one machine, with the entire fuelpath opened up -- that would start up and hold near 45psi for nearly one minute at idle, but then the system pressure would magically start to creep up to 85 psi and start glutting the cylinder... can't explain why, but a new pressure pod cured the problem. That same reg pod had been gunky and cleaned, but from the long-stored machine.
The stock fuelpump does have an iron-steel gerotor inside, and it can most definitely rust inside there -- and much more than the plated injector caps might rust....so it's a good idea to use a fuel treatment that controls the moisture.
Once the fuel fittings are gutted, there is no need for an intake screen in the tank.....it's just something else to clog up, and no longer needed to protect any in-line valves (those 6 components you removed from the suction fuelpath already). You can just pluck the inlet screen off next time, and let the fuel filter do the whole job.
Fuel filters?, the genuine OEM Cannondale version is not junk, as it's a 35-micron and well suited for a decent span of use, and it's compact and best for dirtbikes with a coolant overflow bottle and less space.... but it seems all the chinese rook-a-rike filters and the Napa Gold (Wix's) are 12-micron,...so yes a same-looking substitute filter in a 12-micron is not good for very long on a Cannondale....far too many of those are still being distributed to cdalers out there. When in doubt, change it, no matter how it may "appear", and sure you could switch to the jumbo Napa if you are still married to 1/4" lines from the filter to the pump.
I do have a 25-micron Jumbo filter with 5/16" in-out, and higher flowing pump inlets for a 135 or 90-bend angle for 1/4 andn 5/16.. If you have any disconnect above the filter, it's easy to transition to 5/16" from there -- and yes it makes a flow difference, just like opening up the faucet more...
As mentioned, a good flowing filter will usually appear "emptied out" while running, since the fuel is sucking through fast.
But a full filter means 1 of 2 things;...not flowing much at all! and the air pocket creeped upward (your machine?), or 100% fully self-primed with the air pocket sucked down and through the pump, which does not happen on a cDale with the stock fittings(gutted or opened), or with the stock fuelpump inlet.
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fasternu_674
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- Joined: Wed Mar 10, 2021 10:41 pm
Well I know I will not get a gallon out of my return in a minute. It flows great right off start up but it soon slows down to a dribble on the return side. I think I just need to get a new fuel pump. Fuel reg pod was robbed off of one of my own personal bikes. I know the lines are correct because if they were wrong the fuel pressure would climb, not drop dramatically. I will prolly do an amperage check and more than likely order a new pump. If you guys come up with anything else let me know. Thanks