SOURCE: My FZR 600 is acting up and backfires
I have had several bikes in my time. and keeping the carbs syncranized is very important. Did you put aftermarket pipes on it? try rejeting the carbs up 2+mm that may help the fuel air ratio?
SOURCE: in have a 1985 suzi gs550e it starts but only
I have an intermittent petcock problem with mine, check that. It has a vacuum switch in it that can stick
SOURCE: 1997 Yamaha Kodiak 400, hard to start, once you
I would follow the fuel line all the way check the filter it should be inline and check the pump as well i would say its one of them two.
SOURCE: my gs500f is back firing through the CARB. the
Lean mixtures burn very slowly, at times slowly enough to continue
burning through the power and exhaust stroke, causing a backfire when
the intake valve opens, and that flame gets a shot at the new mixture
charge.
In normal operation, as the engine slows, the fuel delivery from the
main circuit falls off, and the idle circuit is supposed to take over.
If the idle circuit flows insufficiently, that becomes a transition to
fuel starvation.
You can try pointing an unlit propane torch into the inlet air, and see
if you can get closer to an idle while supplying a supplementary fuel
source. You will need to do this in a way that gets propane to both carburetor inlets, maybe rigging a Y with vacuum hoses and
electrical tape...
This started with work on
the carburetors, so the fuel system would be the most suspect. That,
and the fact that it will run at higher RPM would seem to rule out fuel
delivery.
I was looking around at photos while developing this answer (needed to know whether this was a twin or a 4-cylinder), and one resource said the idle speed should be 1,200. I don't know if that's right, but maybe 1,000 RPM is too slow for this motor to keep it together. (I do doubt that, though.)
When I wrote that last sentence, I started to second guess myself,
thinking "What if the fuel shutoff(s) is/are vacuum operated, and as the
bike approaches idle there is insufficient vacuum to hold it/them
open?" But the I rejected that, because there is even less vacuum at
cranking speeds, yet the bike starts.
SOURCE: 1997 Honda CBR 1100 XX.
Clay, you have a tiger by the tail. There are a lot of little parts to the carb system. I will try to assist you in the basics without carb removal. This may require a few replies back and forth. Start by turning off the gas then drain the carbs. Now turn on the gas and check to see that fuel flows into each carb. If gas starts flowing out of all the float bowls, now that the gas is back on, then all carbs are getting gas. To drain the carbs just remove the drain screw on the bottom of each carb float bowl. Two carbs have the drain screw on the left, two have it on the right side. Reply with what you find.
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Thanks for THE very helpful replys i have a Clean tank vents good. Petcok work ing only month old. New fuel lines and aftermarket inline high flow pigiel filter
I removed carbs i found THREE floats bouncing freely and one srickin and not bouncing freely on needle
I also found three of the carb boots were 1# not event tight i could unscrew with fingers. #2. Three of four were cracked beyond normal and hard as bricks.
I would have thought a mechanic that new my probs WOULD have checked those two. Will order parts and let i know how runs
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