Question about Motorcycles
Had carb rebuilt and valves adjusted compression is at 90 and carb still has backfire in it in idle runs fine on choke
Hi Jesse, and the usual suspects are:
1. Loose, corroded, or broken battery cable ends inside the cable harness especially the "NEGATIVE" cable at both ends.
2. A severely drained battery.
3. Faulty main circuit breaker and or connections.
4. Faulty ignition coil and or connections.
5. Faulty spark plug, oil or gas fouled, wrong heat range or service type, wrong gap, loose in the cylinder head, broken electrode or insulator.
6. Faulty spark plug cables, leaking or broken, internal damage.
7. Faulty ignition module, switch, CKP, MAP, CMP, sensor and or any connector in the ignition circuit could have corroded, loose, or broken pins/sockets
8. Burnt exhaust valve or air leak in the exhaust system.
For more information about your issue, please visit the websites below. Good luck and have a nice day.
1998 Yamaha ATV Service Repair Workshop Manuals
Posted on Oct 04, 2015
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Posted on Jan 02, 2017
Here are two solutions for you:
A - Take the carberator off and soak it in some good quality carb cleaner for about 1/2 an hour. That should take care of any residue in the carbs.
B - Alternatively (and for the less technical minded) there is a great product called Sea Foam. Try to find it at your local CSK auto/NAPA/Wal-Mart. Pour a small amount (maybe 1/4 ounce) into each cylinder chamber (take out the spark plugs), try to pour a small amount into the carbs (a turkey baster works great for this), and pour the rest into the gas tank. Let it sit for 5-10 minutes, then start it up. *NOTE - the bike will start VERY hard at first until it burns through what's in the cylinders. ALSO the fumes will be EXTREMELY strong and suffocating - make sure you do this OUTDOORS preferably, or at least in a VERY well ventilated area.
Good luck - I know how frustrating these things can be! :)
P.S. - I am a proud owner of a V-Star 1300 - great bikes! :)
Posted on May 26, 2009
When I recently ordered parts from Saber Cycle, they included a piece of information that pertained to my motorcycle, which is also a 1983 Honda Goldwing GL1100 Interstate. Here is what it says, I hope this helps:
Air Cut-Off Valve
The air cut-off valve is an extremely important part of the fuel/air intake system that is frequently missed even my competent mechanics, most of whom are not even aware of its existence or how it functions.
Every GL1000 has one, located in the air intake tube, between the air cleaner box and the manifold. Every GL1100 has four, located in the top air intake passage of each carburetor, and every GL1200 has one located in the plenum box below the air cleaner box similar to the GL1000.
These valves are "air blockers", along with the carburetor o-rings, serving to restrict air flow and increase the fuel/air mixture ratio when the carb slides are in the lower RPM range, up to closed so that the machine will start and idle smoothly with virtually no choking and accelerate rapidly, with no stumble or hesitation.
When typical starting requires heavy and prolonged choking to keep the bike running, when stalling and hesitation occurs even while "warmed up" and when backfiring pops while the throttle is shut off while cruising, most people will start fooling with the air screws to try to overcome the problem, only making it worse along with reducing their gas mileage.
Running with dysfunctional air cut-off valves can causes severe engine damage or failure. When the valves are dysfunctional, the engine pulls nearly total air in the low RPM range through the carbs and on to the combustion chamber. The fuel/air ratio is extremely poor with pre-ignition long before the normal 38 to 40 degree firing point, generating an enormous amount of heat, with no power, which is trapped a longer period of time in the cylinder before the exhaust valve opens.
This heat goes mostly up through the cylinder head, gradually incinerating the head gaskets and allowing engine coolant (anti-freeze) to seep into the engine. You can easily spot when you are in trouble by a puff of bluish-white or white smoke on first starting the engine. Don't leave it alone. Change head gaskets immediately or you could take out your bottom end bearings, ruining the engine.
For those of you installing new exhaust systems, you will discolor your headpipes, either blue (lean state) or gold (rich state). You can destain your pipes using "blueaway" or "blue-off" but be careful not to rub the chrome, just dab gently.k These compounds are usually purchased at a Harley dealer or Harley oriented aftermarket shop.
Honda genuine pipes, like many Yamaha pipes, have a double wall for a portion of the headpipe which masks this discoloration-but also masks a bad state of tune. Even if your pipes are original and still in good shape, don't think that you are OK if the bike has any or all of the dysfunctional air cut-off valve running and performance characteristics.
If your 1975 to 1987 Gold Wing is not getting 50-58 miles per gallon (20-23 KM/Liter), you have one of the most obvious signs of trouble. It is likely your air screws have been backed out to try overcome the effects of the poor running, stumbling, starting and stalling and quitting.
Resynchronize all four carbs to the #3 carb vacuum level using mercury carb sticks or vacuum dial gauges. Stay with strict use of the setting levels in either the Honda, Clymer or Haynes manuals. Do not attempt to tune any other way! Guessing will not work and can cause considerable engine damage!!!
Posted on Sep 26, 2009
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