What is happening?!? The carburetors are gummed up. When fuel cannot flow out of the carburetor as fast as the fuel pump supplies it, the fuel overflows the carburetor.
Solution: Clean the carburetors.
Required tools:
Phillips screw driver
12 mm socket and ratchet
Allan wrench for fuel tank bolt - unsure of size
Needle nose pliers
Carburetor cleaner
1. Run the bike with the fuel valve open.
2. Turn off bike.
3. Shut off fuel value. We want some fuel in the carbs for this procedure.
4. Remove the seat. This is easily done with a 12 mm socket and ratchet.
5. Remove the side covers.
6. Remove the fuel line from the fuel valve. Use needle nose pliers to remove the retaining ring and slide the fuel line off. It can be tough to get out of there!
7. There is a small hose on the bottom of the tank that leads to underneath the seat. Disconnect this hose that normally resides under the seat.
8. Remove the bolt with an allen wrench the secures the tank.
9. Pivot the tank upwards a few inches and slide it back. The tank's front simply rests on two big rubber-coated prongs. Be careful to not hit your handlebar riser with the tank and chip the paint!
10. Now you are at the air cleaner housing. There is a strange rubber goose neck air intake. It is secured by two screws. Remove the screws and remove the air intake.
11. Remove all the screws on the top of the air box. There are about 13. You will also need to remove the plastic covers that attach to the frame behind the tank. Easy work, but a lot of screws. Organize your screws because they are all different sizes!
12 Remove the air cleaner housing cover. It will take some work to get it out of the way. You will see this:
 |
| Top of air cleaner box removed |
14. Spray carb cleaner down each of the four horns. Open the throttle while spraying the cleaner to prevent a stall. If it does, just fire it back up. You should be able to run with no fuel for several minutes!
15. Reassemble and ride!
Next time I have to park the bike, I will add a fuel stabilizer!
same problem. I will do this thanks for the info you're a life saver =)
ReplyDeleteI tried this but still leaking out of the overflow but I noticed some was dripping out fro the screw beside it! Thoughts???
ReplyDeleteFound this post through an Internet search this week when my Magna was leaking gas from the fuel valve. I was a little apprehensive about disassembling part of my bike by myself, but I picked up a can of carburetor cleaner, grabbed a few tools, and dove in. A leisurely 30-40 minutes later, I had my bike back together and ready for a test ride. So far, so good -- no more leak. Thanks for taking the time to post this "how to" for us.
ReplyDeleteI'm a new rider. Got a 98 Honda Magna 750 and I can't find the Fuel Pump... does it have one?
ReplyDeleteNo, the 96 does not have a fuel pump, strictly gravity feed and vacuum to open fuel valve diaphram.
DeleteWhat about the 99 does it have a fuel pump
DeleteHusband is trying this to clean the carbs. His 98 Magna will only run w/ the choke on but as soon as he pushes it back in; the bike dies. It sat for several months. Any thoughts? He's put fresh fuel in it, Sea Foam, and now the carb cleaner into each of the horns... hopefully this does the trick. But any other suggestions would be appreciated.
ReplyDeleteHi, I have similar bike 1994 Magna vf750. Did not ride it for a couple of years and this year decided to pull it from the garage give it a clean and ride it - but severe gas leak developed as soon as I started to prime the carbs. Gas leak appeared on the right side bottom of the carbs assembly at the bottom of the floats covers. It seamed leaking right from the bolts that holding pans to the carb. There simple instructions on youtube how to take carbs out. It took me 30 min of no rush time to remove carburetor. Removed float pans and I can tell that gasket was solid like a brick - no flexibility, plus all around the perimeter were some sort of oxidation gown right on the gasket, it was solid to feel and easy to scrab. The fact this stuff is growing righ on the gasket where it should sit snug and tight against aluminum body tells me gasket is completely shot and not performing its function. Replacement gaskets on ebay all 4 for $22. Replaced and it runs like new now - no more leaks.
ReplyDeletehere is the pic of how the gasket looked when floats pan was 1st removed
ReplyDeleteclick on the link below to this picture from my google photos:
https://photos.app.goo.gl/9abvHGZEZyzNtcyn6
p/s after you remove old gasket make sure clean gently gasket saddle channels on the pan and clean carb body where the gasket will make contact to ensure new gasket works as intended.
Hey BP Wright, Thanks, I sprayed carburetor cleaner in carbs while running engine and (#1)carb leaking stopped. :) I installed 4 new spark plugs also, but engine is still running erratically, runs for a minute or two then stops (with gas tank connected and on).
ReplyDeleteI know this is a few months late however for whats its worth i will post it anyways. The carbs have to come off and cleaned. with ethenol in gas moisture in these old tanks causes rust and debris. It makes its way to the carbs and clogs them all up. If rust inst the issue, the carbs get gummed up from sitting when not properly maintained. The carb cleaner works if you have a minor issue but rest assured that if its bogging down when you accelerate even with the coke on, its time for a carb cleaning. Don't be intimidated, take plenty of pictures and label all the hardware and you should be ok.
ReplyDeleteAs for the leak from the carbs, this is a separate issue. Due to the gravity fed gas tank the petcock is usually shut off when not riding. On the magna there is an auto fuel cut of valve. The diaphragm in this valve is known to fail cause continual flow of fuel thus flooding the carbs cause leaks and even allowing fuel into the oil. Pull the dip stick if you smell fuel the diaphragm is shot.
Word of caution if you decide to clean the carbs yourself DONOT touch the Synchronization adjustment screws especially if your bike was running well before you parked it.
Wish someone told me all this before I started taking mine apart. live and learn. God bless you all and God bless America!
I have an 95 magna 750 and I had my tank repainted last spring. It went to the painters shop with the fuel petcock still on. Came back 2 months later with a beautiful paint job and my petcock removed. I tried to reinstall it but it leaked. Thoughtaybe a gasket or O ring was needed. The fuel filter in the tank seemed ok. But no O ring. Can I delete the filter? I have a good aftermarket one just after the petcock.
ReplyDeleteWhat size is the fuel tubes O-ring size. 10×2×8mm or 12×2×8mm?
ReplyDelete