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Post by kawonda750 on May 23, 2022 7:58:56 GMT -5
That is what my H1 is doing too. Idles fine but as soon as it goes into gear and revs it backfires on the right cylinder. I was thinking coil.
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Post by zambia on May 24, 2022 14:00:22 GMT -5
I've gone back and forth between fuel and fire. At the moment, I'm back to fuel. It seems weird and/or unlikely that the carbs would "go bad" just sitting minding their own business all winter. But then I wondered if maybe the carbs were on the edge of having too high a fuel level.. and the top end rebuild created greater suction in the intake (20 psi more compression) - so now they are flooding the cylinder? The left carb was overflowing when I put things back together and I messed around with fuel height until I could keep it dry on the side stand - it runs the best and has a lower fuel height.
I have swapped out EVERY single piece of electrical equipment that might be faulty (possible exception of a broken wire or faulty ground).
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Post by zambia on May 24, 2022 15:31:49 GMT -5
That's a weird one... Have you pressure tested it? I don't have the gear or know-how for that.. but compression is 140-145.. I wondered about that but I feel the seals are good. The one decent ride I had, it wheeled like nobody's business.
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Post by pipe welder on May 25, 2022 8:14:05 GMT -5
My z1 fired up and sounded good last year but fuel was leaking from the “T’s” that feed from the tank. No time to fix so I drained the tank and the carb bowls and parked it.
A couple of weeks ago I pulled the carbs off and replaced the “T’s” . No more leaks but it wouldn’t run. Pulled them again. Opened them up this time and the pilots were plugged, residues on everything so I did a good cleaning and it fired up right away.
No idea why that happened with all the fuel drained.
I drain my h2 each year for the winter and never had an issue running it the next season.
In case you have a similar issue that I had with the z1, An easy test would be: Possibly you have some other mains and pilots and a needle and seat from a different carb. Temporarily instal them on that left carb and see if anything changes. Or try a completely different carb if you have a spare or a doner bike
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Post by Curtis on May 25, 2022 9:13:16 GMT -5
Draining carbs is not the last step With the fuel off - carbs drained - give the bike full choke and try and start it for 10 - 15 kicks Any remaining droplets in the carbs/jets/orfices will then be sucked up and gone.
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Post by lc on May 25, 2022 12:13:34 GMT -5
Could the choke plunger of the bad cylinder not be seating properly in the carb body?
How is tbe condition of the rubber end of the choke plunger?
Is the slide of the effected carb properly synced with the other carbs, both at rest(idle) and under cable operation?
J
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Post by Walms on May 26, 2022 5:21:06 GMT -5
You mentioned that the center cylinder was flooding then you said “the centre cylinder was drowning and backfiring like a world champion at a chili eating contest. I've swapped carbs and the problem remains with the centre.” Is it possible that you are getting some contamination in the fuel or bad gas. Hard to explain why the flooding issue remained after swapping the carb out. Obviously fuel problems should affect all the carbs but swapping out that carb should have stopped the flooding. Have you tried swapping the centre carb to another cylinder yet?
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Post by zambia on May 27, 2022 10:29:07 GMT -5
You mentioned that the center cylinder was flooding then you said “the centre cylinder was drowning and backfiring like a world champion at a chili eating contest. I've swapped carbs and the problem remains with the centre.” Is it possible that you are getting some contamination in the fuel or bad gas. Hard to explain why the flooding issue remained after swapping the carb out. Obviously fuel problems should affect all the carbs but swapping out that carb should have stopped the flooding. Have you tried swapping the centre carb to another cylinder yet? Oh yeah - did that first thing. Also swapped the entire choke assembly from a different carb. I will say that the left cylinder runs best and the fuel level is the lowest (by 2mm) but it is sharper, hotter and the plug is dry. So I'm going to put that carb in the middle and see what happens
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Post by Walms on May 27, 2022 14:41:59 GMT -5
One thing that I came up with for confirming the carb float level seals are sealing at the height you expect, I held the carb upright with a length of hose attached to the inlet port. I would blow into the tube, at the same time raising the float and know the point where the the seal contacts and actually creates the seal. It was very repeatable and very easy to realize the setting. In saying that, also check you don't have a leaking float at the same time.
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Post by zambia on May 29, 2022 7:50:36 GMT -5
These 38's are tricky because the floats are fixed in the bowls and slide up and down on little rods. I have a clear tube which screws into the bottom of the bowl but the whole thing seems kind of sketchy. I put the bowls on, hook up the gas line then carefully remove the bowls and see how full they are .. PIA
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Post by kawonda750 on Jun 15, 2022 13:03:16 GMT -5
Did you ever figure this out ?
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