Greetings all. I know this is a car forum, but I don’t trust any of the motorcycle forums I frequent for this kind of issue. I trust the regulars in this forum much more.
About ten months ago, I put my 2003 Honda Nighthawk 750 into storage. I did all the right things. I added fuel stabilizer to the gas (a double dose), and I ran the engine long enough to get the stabilized fuel through the entire fuel system. While the engine was running, I turned off the fuel valve and waited for the engine to stop running. Then I removed the key from the ignition and hooked up a smart battery charger and put it away.
Last night, I finally started it up. It started right up, but I noticed gasoline pouring out of the bottoms of the four carburetors. It looks like I will probably need to have the carbs rebuilt.
What do you think went wrong? I have been slowly (when I can afford it), customizing this bike to make it into a long distance touring machine, so I never planned to make it a daily rider. With an air-cooled engine, it wouldn’t make a good daily rider since I would have to warm it up using the choke even in warm weather. My other bike (a 2005 Honda Shadow Aero), makes a good daily rider because I can start it right up in warm weather without using the choke. How can I keep this from happening again?
Your float needles dried out or are sticking. It floats and presses into the incoming fuel flow to stop it when the float is at the proper level. If you’re completely unfamiliar, think about how a toilet fills…the ball lifts, and at a certain point it stops the water flow. Push down, and a bit more water flows in until you let it float again.
Use a conatiner to catch the fuel, and a screwdriver handle to rap the carbs when they’re running (and leaking). It shouldn’t matter too much where you rap it, either, since it’s a single unit and any shock will go through the whole unit, but if you can get at the part where the float bowl mounts to the base you may be better off.
Carbs, gasoline, sitting unused for 10 months. It’s a bad combo, but one that’s hard to avoid or prevent. Some of the gas evaporates, some turns to varnish. A constant problem for motorcycles, snowmobiles, lawn mowers, and snow blowers here in Minnesota.
Can you remove the bowl underneath the carbs? You can probably spray some carb cleaner in there and get the float working again. Maybe clean out some of the jets too while you’re at it.
Whitey, I’d Guess The Float Needle Valves Are Not Sealing. The Carbs On This Aren’t A Lot Different From My Old CB750K In The Back Of My Garage. How To Prevent It ? I Think You Tried, But It Didn’t Work.
Look at the float chamber (bowl) #4. It fills with gasoline when you open the tank valve. As the gas level rises it lifts the float #3 and it lifts the float valve (needle) #17.
The float valve needle goes up into a hole (seat) in the carb body to stop the gas from flooding in. When it’s working properly, without the float/float valve being stuck, the fuel level is regulated properly and gas doesn’t overflow.
This should not require a rebuild, but rather just freeing up the needle valve(s) that are sticking. This is fairly common with needle & seat carbs.
I stored several motorcycles (up to 7 at one point) and one was a 750cc Nighthawk. You did what I did with one exception. I did not run the carbs out of fuel. I left the stabilized fuel in the carbs. I figured there are seals and stuff and keeping them “wet” was better than letting them dry out.
I’d go along with stuck floats. Just the vibration of running the motor could free one or more of the floats up. Tapping with a rubber mallot might help. The inboard 2 carbs could be tough to reach.
Thanks for the help guys. This is extremely useful, and I’ll take a whack at it this weekend to see if I can free the float needles. If they are stubborn, I’ll try some carb cleaner.
I’ve learned a couple important lessons. One is I might not want to run the carbs dry next time. The other lesson is, even with fuel stabilizer, the gas has turned yellow, so it really shouldn’t be stored for that long without being ridden. I will have to take it out and ride it more often.
I’ve only seen one gas station in Florida that advertises non-ethanol gas, and it’s not in my area. So, although it would be a good idea, I don’t use non-ethanol gas.
I never run mine dry for this reason.
I routinely store mine for about 6 months every year.
I treat and run long enough to insure the bowls are full of stabilized gas and then shut it down. Mine have rubber hoses going from the carb vents to below the lowest point on the bike to make sure any gas discharged doesn’t run down the bike parts. For years, I plugged those lines with golf tees thinking it might slow down evaporation from the bowls. I stopped doing that many years ago now and haven’t noticed any difference (knock on wood). One issue with running dry I did find out the hard way, the older style, fiber gaskets seemed to fare better if left immersed in fuel than allowed to dry out.
I saw a gas station with a large sign that read, “ETHANOL-FREE GAS!!!” on one of my recent trips to Jacksonville. I guess there are some marinas that sell ethanol free gas in my area, and it might be worth the high price they charge next time I store my bike.
For whatever it’s worth, I will add what I have been doing for years to two different bikes. My two bikes always start in the spring after winter storage with only a little reluctance but not always. I live in one the northern tier of midwestern states. I can run the carb dry on one of the bikes but the other has a vacuum operated gas valve so I simply stop the engine for that one.
Remove the batteries, store in a heated place with a float charger or a battery maintainer. I see no advantage of one over the other.
Use non alcohol gasoline. It is available in rural areas at some gas stations as either mid grade or premium grade gasoline.
I never use a gasoline stabilizer. It is inexpensive, easy to use and I do have a bottle of it but just don’t use it.
Store the bikes in a non-heated garage.
That is all, no other actions.
I also have a riding lawnmower. It also gets non alcohol gasoline and no stablizer but leave the battery installed and don’t use a float charger or maintainer. It is kept in an unheated outdoor storage shed. It also starts easily in the spring.
To the OP: Since all carbs leaked, it seems logical to take one apart to inspect the float and float valve. If you destroy the evidence with your inspection, you have three more to work with.
i agree that fuel stabilizer is not necessary if you are storing for less than 1 year. if you plan on more than that, consider it. Otherwise you are just wasting money. fuel doesn’t go bad like the old days. (<1yr)
secondly, if you have to choke it to start all of the time, it is saying that you have varnish and stuff in your carbs. once you have a good carb clean, you should notice that the choke should not be necessary. based on this, yes you could use a cleaning.
Forgive me if I seem ungrateful, but I am going to continue to use fuel stabilizer. Even with fuel stabilizer, the gas turned yellow. I would hate to see what it would look like if I hadn’t used the stabilizer.
Also, I’ve never seen an air-cooled engine (even one that was brand new), that would start without using the choke. It’s funny, but every time someone has tried to sell me an air-cooled motorcycle, and given me the “you don’t need to use the choke to start it” shtick, the bike wouldn’t run right until we used the choke to start it and let it warm up.
Frankly, you’re answering questions I didn’t ask. Again, I don’t intend to seem ungrateful, but I’m experienced enough to know what happens when I don’t use fuel stabilizer. I’ve learned important lessons about how long I can store my bike (WITH fuel stabilizer), and not running the carbs dry, so I am open to suggestions on things I can add to my process to improve my chances, but I am not going to do less than I do now since I believe that would be foolhardy.
When I store my bike for the winter I normally put stabilizer in the fuel and run the engine long enough for the fuel to reach the carbs and leave fuel standing in the float bowls. I also remove the battery cables and hook up a small charger that cycles on/off as needed to maintain a the battery. I’ve been using this method for the past several years after having problems with sticking floats and needing to rebuild the carbs on my '82 Yamaha 1100. I also use ethanol laced fuel. We had just moved to a new home last fall and I didn’t have a garage or storage building to store the bike in last winter so it sat outside from Oct. 2010 until about Mar. 2011 and wasn’t started, yet when I started it for the first time this year it started fine.
Turn off the fuel valve and run the carbs dry again…Tap on all the carbs with something like a 10" long 3/8 extension…Turn on the fuel valve and tap on any that still leak…If they persist in leaking, at minimum, you will have to remove the float bowls, remove the floats and clean the needle and seat…Sometimes this can be done with the carbs on the bike and sometimes not…