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Hi, Juv69576 and the usual suspects are:
1. Severely discharged or a damaged battery, should have 12.5 volts or better and be able to pass a load test if necessary.
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. Spark plugs in bad condition or partially fouled.
4. Spark plug cables in bad condition and leaking check for spark leakage in the dark
5. Spark plug gap too close or too wide.
6. Faulty ignition coil, module, and or sensor.
7. Loose, dirty, or corroded ignition module connector at crankcase.
8. Faulty CKP or CMP, MAP, ETS, ATS, TPS, O2 sensor.
9. Intake air leak.
10. Water, dirt, or rust in the fuel system, carburetor and/or filter.
11. Old dead or bad fuel.
12. Fuel tank vent system plugged or carburetor vent line closed off.
13. Vacuum line from intake manifold to fuel valve is broken, cracked, pinched, or missing.
14. Carburetor controls misadjusted.
15. Damaged carburetor.
16. Incorrect valve timing.
17. Weak or broken valve springs.
18. Damaged intake or exhaust valve.
19. Check for engine trouble codes
For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have nice a day. 2005 R6 power loss misfiring R6 motorcycle cylinder misfire power loss fault finding spark check... 1999 2002 Yamaha YZF R6 Service Manual R6 Moto Data Project OEM parts for Yamaha http://mybikemanuals.com/yamaha/yamaha-yz-owners-manuals
with the bike being new you wouldn't think it's the spark plugs, but you must remember that those are the first plugs that motor has had in it. the plugs are always supposed to be changed at the first service. try changing them and see what happens.
Check the coilpacks, coil leads and clips for shorting or,arcing ( Fire the bike up in the dark and have a look). There are two coil packs so try swapping them and see if the fault changes cylinders, that will isolate the problem.
The firing order on your bike is 1,3,4,2. These bikes use what is called a wasted spark system. They fire whenever the piston reaches top dead centre.
That is to say they fire on top dead centre compression as well as top dead centre rock-over( exhaust/inlet ). Each coil has two leads on them.
The left coil goes to number 1 & 4 cylinders.
The right coil goes to number 2 & 3 cylinders.
The GPX 750(like most road bikes) have a resistor type spark plug cap on them that was prone to cause problems.
To test the coils/caps, use a multi-meter to test their secondary resistance.
To do this set the meter to kilo-ohms(1000 ohms), place one meter probe in one plug cap & the other probe in the other plug cap( i.e. 1&4, 2&3 )
The meter should read 10kilo-ohms to 15 kilo-ohms.
If it reads higher than that try un-screwing each cap & test the coils with the caps removed by probing the leads. If the coils(without caps)read about 5 to
10 kilo-ohms, check the caps.
The caps should read 5 kilo-ohms each.
It is very common to find these open-circuited.
Replace any open circuit caps.
I hope this has been of some help.
Otherwise if you can be a little more spacific with your problem I will try to help further.
hi paul here,
the coil on my bike turned out to be the problem after checking wires, connections and plugs. brought a used single fire.
tried it out after being told that coils usaully go all bad not just half.
have not had the problem since and i was conteplating buying ignition and coil combo for hundreds.