Hi, Anonymous and the usual suspects are:
1. Severely discharged or a damaged battery should have 12.5 volts or more and be able to pass a proper "LOAD" test if necessary, you may have a preliminary reading of 12.5 volts or more but little or zero amperage the battery is faulty and must be replaced, AGM batteries fail in this scenario more so than lead-acid batteries.
2. Check battery terminals for damage or corrosion, check the battery cables at "BOTH" ends for loose, corroded, or broken connectors, "INSIDE" and outside the cable harness, perform connector wiggle test and check cables with an ohmmeter if necessary.
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 check for spark leakage in the dark.
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.
9. Improper valve clearance (too tight).
10. Check for generated diagnostic codes.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day. http://allmototips.blogspot.com/2017/03/the-backfire.html https://www.istorya.net/forums/automotive-74/481688-q-yamaha-mio-sporty-backfire.html Yamaha Mio Service Manual https://www.partsfish.com/page/oem-parts-for-yamaha Yahaha MIO soul owner manual
Hi, Anonymous and the usual suspects are:
1. Fuel tank empty.
2. The fuel tank has old dead gas.
3. Fuel tank bottom contaminated with ethanol sludge, dirt, water, rust, etc.
4. Fuel supply valve/petcock turned off.
5. Fouled spark plugs.
6. Engine flooded as a result of overuse of the choke.
7. Vacuum hose to the fuel supply valve/petcock disconnected, broken, cracked, or pinched.
8. Fuel valve/petcock or filter clogged.
9. Fuel line to carburetor or throttle body pinched, kinked or blocked.
10. Carburetor float stuck.
11. Fuel injectors clogged.
12. Fuel injectors stuck open.
13. Quick disconnect check ball stuck.
14. Compression below 75 PSI.
15. A stuck-bent-burnt valve.
16. Improper valve clearance (too tight)
17. Severely discharged or a damaged battery should have 12.5 volts or more and be able to pass a proper "LOAD" test if necessary, you may have a cursory reading of 12.5 volts or more but little or zero amperage the battery is faulty and must be replaced, AGM batteries fail in this scenario more so than lead-acid batteries.
18. Check battery terminals for damage or corrosion, check the battery cables at "BOTH" ends for loose, corroded, or broken connectors, "INSIDE" and outside the cable harness, perform connector wiggle test and check cables with an ohmmeter if necessary.
19. Loose or corroded wire connection at the coil or plug between ignition sensor and ECM module.
20. Spark plug cables in bad condition and shorting check for spark leakage in the dark, cable connections are loose or connected to the wrong cylinders.
21. Ignition timing incorrect due to a faulty ignition coil, ignition module or MAP, CMP, CKP, O2, TPS, ETP, IAC sensors.
22. Faulty neutral, clutch, kickstand safety switch.
23. Faulty fuel pump or fuse or relay.
24. Faulty or corroded run/stop switch.
25. Tilt sensor needs a reset.
26. Security system not disarming alarm needs a reset.
27. Check for engine trouble codes.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day. What To Do If Your Motorcycle Doesn Start 3 Things to Look for When Your Motorcycle Won Start The Allstate Blog https://www.worldcat.org/title/yamaha-v50-v75-v80-v90-owners-workshop-manual/oclc/12810337 https://www.partsfish.com/page/oem-parts-for-yamaha https://www.manualslib.com/manual/474076/Yamaha-Np-V80.html
Kick stand up or down,clutch in or out? Tranny in neutral with neutral lamp on? Did it start after that one time or it hasn't since? Check switch contacts for both power and start,test start solenoid and ensure power down to starter
Check all ground points and clean em at block,frame and batt posts also. Coat all terminals with dielectric grease. Best corrosion protection.
It sounds like the carb jetting is plugged up so that carbs should be removed and cleaned! When you first start the bike keep it idling by having someone hold it on and at the same time light touch the front and rear exhaust pipes. The carb that is working will have a hot pipe and the one not working will be cooler or cold.
First off, I put a brick under the kickstand to get my bike near level...then i gathered the tools needed. 5mm Alan Head (Hex) Bit, 8mm wrench, phillips head screwdriver, and a vacuum pump (not necessary but very helpful if you're doing it solo.
Next step is to remove the left rear cylinder side cover. three 5mm bolts hold this in place.
Unscrew and remove the resevoir cap and diaphram carefully. Cover your paint with a towel (I was probably a little overdue for a fluid bleed...)
Suck out the old fluid from the resevoir using the pump (or a turkey baster) and refill with new DOT 4 brake Fluid (or DOT 3 or DOT 5.1)
Attach a plastic tube to the clutch bleeder valve, set up your vacuum pump, and loosen the valve using an 8mm wrench.
Now, get to pumping...watching the level in the resevoir as to not let it suck any air. When the fluid coming out of the valve is clear, the system is flushed.
(NOTE: if you are doing this by hand, (1) loosen the bleeder valve, (2) squeeze and hold the clutch lever, (3) tighten the valve, (4) release the lever...then repeat 1 through 4 about 50 more times being sure to watch the fluid level in the resevoir)
Once you are done, close the valve to 4.3 ft/lbs and refill the resevoir. Then replace the diaphram and resevoir cap.
Put the rubber cover on the bleeder valve and re-install the left rear cylinder cover. Check the fluid is at the appropriate level...