Will it idle with the choke pulled???
What to you mean the idle speed is "set all the way" closed or open
What to you mean the idle speed is "set all the way" closed or open
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A Tale of 4 (Small) Cylinders - My Honda CB400F
- Thread starter philipbarrett
- Start date
Carbs have been completely rebuilt & the bike was running fine about 8 weeks ago.
Nope, dies on choke. Idle speed set to maximum idle. Like this...
[ame="https://www.youtube.com/watch?v=XU9mhfNygNA"]Billy Idol - Live at Rock am Ring-Rebel Yell.avi - YouTube[/ame]
Have you removed the carbs? I think there's like a "choke tube" that connects them all. Ensure that's in place, if it exists at all.
Let me tell you a story about my father-in-laws boat. Last month it ran. This month it does not. I went over to check it out the other day, as asked him about the fuel quality/age. He said it couldn't be the gas, he treated it, and its only a month and a half old. I had him pump up the primer bulb while I held the pressure relief valve on the fuel rail open. Out came some green watery crap.
What I'm saying is it could be the gas. After I purged the algae and water laced ethanol that had fallen out of the gas, and got picked up by the pump, the boat started and ran. It wouldn't idle, but it would run if you gave it throttle.
I picked him up some ethanol free 92 and now it runs fine.
Let me tell you a story about my father-in-laws boat. Last month it ran. This month it does not. I went over to check it out the other day, as asked him about the fuel quality/age. He said it couldn't be the gas, he treated it, and its only a month and a half old. I had him pump up the primer bulb while I held the pressure relief valve on the fuel rail open. Out came some green watery crap.
What I'm saying is it could be the gas. After I purged the algae and water laced ethanol that had fallen out of the gas, and got picked up by the pump, the boat started and ran. It wouldn't idle, but it would run if you gave it throttle.
I picked him up some ethanol free 92 and now it runs fine.
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4 carbs is beyond me but 2...
I would do this (assuming they are like my old sl carbs):
Pick one and turns its idle speed screw in enough to raise the overall rpm "enough". Then adjust the idle mixture for maximum rpm without touching the idle speed screw. Once you get it to that max, turn its idle speed back down to "enough". repeat. Then set its idle speed back to even with the others.
Do this carb to carb.
I don't know why, maybe gas formulas, but I seem to have to do this every summer and every winter.
You might also treat with some Seafoam.
It is probably something that will work itself out in a hard days ride.
I would do this (assuming they are like my old sl carbs):
Pick one and turns its idle speed screw in enough to raise the overall rpm "enough". Then adjust the idle mixture for maximum rpm without touching the idle speed screw. Once you get it to that max, turn its idle speed back down to "enough". repeat. Then set its idle speed back to even with the others.
Do this carb to carb.
I don't know why, maybe gas formulas, but I seem to have to do this every summer and every winter.
You might also treat with some Seafoam.
It is probably something that will work itself out in a hard days ride.
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Don't know about the 400F, but the 550 I started on in 2007 would die to ethanol eating the factory rubber in the Honda rebuild kits. Westley Seals was able to match up the necessary parts with o-rings of a different material that resisted degradation from ethanol. When I put my wife's 400 together the first thing I did was have Westley set me up with the appropriate carb o-rings that resist ethanol. Never had a problem from the first time we cranked the engine. We always tried to find E0, but it just isn't available everywhere, and the bikes lost power but ran fine on E10 with no degradation over time with the appropriate o-ring material. Not that my wife cared about power--she preferred the look of 4 pipes to match my 550, so that's what she got. Be sure to change the o-rings of the petcock, too, and switch to ethanol resistant fuel lines. Found out about those on the 550.
I expect your new idle problems are from crud of some sort in the fuel system. Did you clean the petcock? Since all four carbs have problems I would expect the source in the tank or petcock. Might also be rust/dirt from the cap or gasket. Seen that before, big pain to figure out. Was the fuel clean when it went in the tank?
The relatively tiny passages of the 20mm Keihins are prone to pugging with the least bit of goop. Might want to prefilter fuel going in the tank and use a couple inline filters under the petcock.
I expect your new idle problems are from crud of some sort in the fuel system. Did you clean the petcock? Since all four carbs have problems I would expect the source in the tank or petcock. Might also be rust/dirt from the cap or gasket. Seen that before, big pain to figure out. Was the fuel clean when it went in the tank?
The relatively tiny passages of the 20mm Keihins are prone to pugging with the least bit of goop. Might want to prefilter fuel going in the tank and use a couple inline filters under the petcock.