My bike was shooting out fuel through one the overflow tube attached to the carb. it stopped doing that so whatever was clogging it is gone. changed the oil, new battery and so on. started the bike it was revving really high even without the choke. Let it go for a little bit thinking it would heat up and drop to normal but never did, then just cut out on me. now i cant get it started.
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Re: 1989 cbr600 revving really high then shuting down
You need to check the choke cable to make sure it is not hung up and flooding the engine pull the cable and see if it feels free if so you might want to take the carbs off and clean check top and bottoms tops may have diaphams in them that may be wore out make sure to take choke cable out from carbs they like to hang up good luc p.s. take pictures as u go if you are unfimilar with rebuilding carbs if the choke is hanging up once you get that taken care of make sure to change your plugs they are probally fouled
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First, where does it come from. It is the overflow for the carb. Comes from a tube inside the carb. Where it goes; basically out the bottom of the bike. It does not connect to anything. just routes down the frame and out the bottom of the bike. It allows any overflow fuel to not get all over your bike.
1. If it only runs in the pri position, that means that the petcock small rubber line is not connected to a vacuum port which is normally in the engine side of the carbs. If you unplug the fuel lines at the petcock and place a vacuum on the smaller rubber line (coming from the petcock)using a hand held vacuum tool or your mouth, the petcock should flow gas each time a vacuum is created and stop when the vaccum stops. If the petcock does not stop flowing gas when the vacuum is released or does not start flowing gas when a vacuum is applied, then the petcock needs servicing or replacing.
2. The fuel is still spilling out because the float is sticking or out of adjustment, or the needle&seat has trash/rust in it or the needles&seats are bad. The float should swing freely on its pivot shaft. The needle sometimes has a spring loaded plunger in top that should freely move back and forth when pressed with the finger and if not replace it or free it up. Setting the floats will vary with manufacturers so consult you service manual for the proper procedure. If the floats are set too high, gas will continue to come out. Some floats have no adjustment.
3. If the tank has rust in it, replace the tank or put a rubber liner kit in it so that it ceases to release rust back into the carbs. Filters will not normally stop rust so the tank needs to be free of rust or fixed with a liner kit.
4. The 4 tubes (if coming from the bottom of the carb fuel bowls) are just overflow tubes and hang down on the backside of the engine. If these 4 tubes are coming from the sides of the carb (about midway up the carb body), these are also vent tubes and just hang. These 4 tubes in question should be smaller than the fuel lines on the carbs and about the same size (maybe a little smaller) as the small vacuum tube coming off of the petcock.
5. If the bike is still boggy and/or hard starting when done correcting the fuel spilling issue, that is because the carbs are still partly plugged. Most carbs do not get cleaned out correctly because most consumers do not have the proper wire drills to go through the jets to get them cleaned out. Some jets get under .010 inch diameter which is really small. The only other way to properly clean the carbs are to totally disassemble them and soak them in a caustic carb cleaner made for cleaning and removing fuel deposits
Hi All carbs have to be synched together using vacuum gauges or manometer tubes Often 1 carb is the control carb which cannot be adjusted, so adjust the others to the same as the control But the early CBR600s has 4 carb sync take-offs 1 in each inlet tract, I know as I owned 1
Sounds like you have a stuck float in the carb. or a piece of crud on the float valve, or a bad float valve. The tube is the overflow tube. Shut off the petcock on the fuel tank. Take the leaky carb off, (you can leave the throttle cable attached) flip it over and remove the float bowl on the bottom. There should be some phillips screws. The hex shaped plug in the middle is the jet access plug. You don't have to remove it. Once it's off, you will see the brass float. Spray the hinge and needle/seat area really well with carb cleaner. LIGHTLY Lift up on the float and spray out the valve needle and seat right below the float really well in case there is a piece of debris causing it not to seat fully. You'll see the valve, it has a clip that attaches it to a little tang on the float. Flip the carb back over to an upright position (before putting the bowl back on) and see if the float drops down. If so, LIGHTLY push up on it and see if it moves freely. If so, and you are sure you cleaned the valve and seat, put the bowl back on, reinstall the carb, turn on the fuel flow and see if the problem is resolved. Most of the time this will fix it. The only expense is a can of carb cleaner and about a half hour of your time if you've never done it.
it's probably just your overflow from the float. it doesn't connect to anything, it just let the fuel overflow come out when your float level is high. if you turn on the fuel petcock and it starts pouring out, your float needle is sticking. clean the carb and the float needle valve assembly and see what happens.
The floating element in the carb. is shaking as well . As you hit the throtle the shaking will lift up the floating element in the carb. house and on the overflow pipe the extra fuel will pass . Adjust the fuel level , check the floating elemnt inside of the carb. case . ( If you not sure , take your bike to the nearest garage . ) I used to play with these things for days . Avoid any damage on the carb . rubber sealant . Keep your eye on the screws ! Some of them are attached with spring as well . Peter
The usual culprit is a blocked vent tube. Verify it's open. The usual
indicator is either a pressure release when you open the gas cap, or
a vacuum "sucking" noise when opening it first thing in the morning.
On a carb equipped bike, the carb overflow lines will leak, but in a
fuel injected bike like yours, it'll be out the overflow vent. The next
time it begins leaking, open the gas cap. It should stop immediately
as pressure inside is released. Good luck.