Top 20 2003 Yamaha YZ 125 Questions & Answers


Hi, Bobby and the usual suspects are:
1. Improper clutch adjustment or not disengaging.
2. Bent shift shaft.
3. Shift fork bent or seized.
4. Gear seized on the shaft.
5. Gear positioning lever binding.
6. Shift return springs weak or broken.
7. Shift return spring pin loose
8. Shift mechanism arm spring is broken.
9. Shift mechanism arm is broken.
10. Shift drum is broken.
11. Shift lever loose on the shift shaft.
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.
https://thumpertalk.com/forums/topic/911069-yz-125-stuck-transmission
http://dirtrider.net/forums3/threads/yz-125-stuck-in-gear.182572
https://www.manualslib.com/manual/582255/Yamaha-Yz125-N-Lc.html
https://www.partsfish.com/page/oem-parts-for-yamaha
http://mybikemanuals.com/yamaha

2003 Yamaha YZ... | 270 views | 1 helpful votes


Hi, James parts swapping is common with most motorcycles when it comes to interchangeable or compatible parts from one model with another "EXCEPT" for the CDI's they are year-make-model "SPECIFIC" the best thing to do is call your local Dealership Parts Department or a reputable independent shop. If your location is not near a shop then go online and find a parts catalog or "FICHE" and match part numbers depending on your criteria.
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.
YZ125 ignition mapping
Cdi bad What going on help
YAMAHA YZ125 Owner Service Manual
https://www.partsfish.com/page/oem-parts-for-yamaha
http://mybikemanuals.com/yamaha/yamaha-yz-owners-manuals

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e

2003 Yamaha YZ... | 146 views | 0 helpful votes


Hi, Dave 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. 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.
17. 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.
18. Loose or corroded wire connection at the coil or plug between ignition sensor and ECM module.
19. Spark plug cables in bad condition and shorting check for spark leakage in the dark, cable connections loose, or connected to the wrong cylinders.
20. Ignition timing incorrect due to a faulty ignition coil, ignition module or MAP, CMP, CKP, O2, TPS, ETP, IAC sensors.
21. Faulty neutral, clutch, kickstand safety switch.
22. Faulty fuel pump or fuse or relay.
23. A stuck bent or burnt valve.
24. Tilt sensor needs a reset.
25. Security system not disarming alarm needs a reset.
26. Check for engine trouble codes.
27. Faulty run stop switch.
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.
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YAMAHA YZ125 LC Owner Service Manual
https://www.partsfish.com/page/oem-parts-for-yamaha
http://mybikemanuals.com/yamaha/yamaha-yz-owners-manuals

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e

2003 Yamaha YZ... | 88 views | 0 helpful votes


Hi, Anonymous I feel your pain you just dropped a ton of "DRACHMA" on rebuilding all or part of your engine and a couple of hours or days later it dies or locks up and you want me to tell you how much it will cost to fix. Unfortunately due to the magnitude of yesterday's solar flare the batteries in my crystal ball are dead and the circuitry in my mental telepathy headset was melted. Let me break it down for you.
1. Was the work done by an experienced trained professional technician or someone with good intentions that was not qualified to hold a wrench?
2. Was the proper break in procedure explicitly followed using the proper break in oil and changed as directed?
3. If your bike is used for off road abuse or competition there is no warranty in most cases.
4. If you have a street bike that had performance goodies installed no warranty in most cases.
For more information about your issue and valuable "FREE" downloads that you will need please click on the blue links below. Good luck and have a wonderful day.
Yamaha YZ125T1 Owner Service Manual
Yamaha YZ125T1 Parts Catalog
http://mybikemanuals.com/yamaha/yamaha-yz-owners-manuals
Yamaha YZ 125 2002
Yamaha YZ125 Wikipedia

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e

2003 Yamaha YZ... | 56 views | 0 helpful votes


Hi, Kaydriona not really does your car rust when you take it to the bike wash lol they are designed to be waterproof by the time you ride it home it's nice and dry, for more information about your question and valuable "FREE" downloads that you will need please click on the websites below. Good luck and have a nice day.
http://moto.tt.free.fr/explorer/YAMAHA_2005_YZ125T1_Service%20Manual_anglais.pdf
OEM parts for Yamaha
http://mybikemanuals.com/yamaha/yamaha-yz-owners-manuals
Yamaha YZ 125 2004

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e

2003 Yamaha YZ... | 55 views | 1 helpful votes


Hi Simon, if you are talking about a spark plug where it connects to the spark plug cable the usual suspect is improper use of spark plug installation tool (I am guilty of that crime) or a faulty batch of spark plugs from the manufacturer, try a different brand just for conformation and I am sorry you can't find the first and best tool you ever bought for your Aprilia but despair not for a mere $10 you can download another one. For more information about your issue, please visit the websites below. Good luck and have a nice day.
DOWNLOAD 2003 Yamaha Yz 125

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e

2003 Yamaha YZ... | 86 views | 0 helpful votes


No oil goes into the crank case as it is a 2 stroke. The oil is premixed in the fuel at a 30-1 ratio.
The gear box takes 10w-30 se oil.

2003 Yamaha YZ... | 184 views | 0 helpful votes


Premixed fuel at a 30-1 ratio.

2003 Yamaha YZ... | 56 views | 0 helpful votes


Hi, Craig the answer to this question is way above my pay grade for this situation, I would call or visit my local dealer or reputable shop's service/parts department and inquire about any possible quick fix, answers, or parts inquiry.
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.
https://thumpertalk.com/forums/topic/511018-cracked-case
https://m.vitalmx.com/forums/Race-Shop,42/YZ125-case-repaired-Common-problem,1301169
YAMAHA YZ125 Owner Service Manual
https://www.partsfish.com/page/oem-parts-for-yamaha
http://mybikemanuals.com/yamaha/yamaha-yz-owners-manuals

2003 Yamaha YZ... | 41 views | 0 helpful votes


If it does stay in gear when barely throttled but does not stay in while under load, the engagement dogs on the gears(inside the engine) are bad and the engine will need to come apart to repair it.

2003 Yamaha YZ... | 154 views | 0 helpful votes


wear or play on the gear selector drum,could even be the gear selector plate on the end of the drum is loose its star shaped with a central bolt or screw,check the locator spring also.

2003 Yamaha YZ... | 93 views | 0 helpful votes


Service manual says oil capacity is 19.4 oz. per leg which is 573.726 ml per leg. Be sure that you have drained all the old fork oil out first.

2003 Yamaha YZ... | 1,533 views | 0 helpful votes


Hi, Anonymous the starter drive/Bendix/clutch is a mechanical gear driven component that engages the clutch pack ring gear to turn over the engine. It has an internal mechanism that allows the gear to turn in one direction and once the engine starts allows the drive gear to free spin. If gear free spins in both directions then the drive gear has failed, it is not serviceable and needs to be replaced. 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.
ATV Connection
Yamaha YBR 125 starter clutch rebuild engine rebuild video coming soon
Yamaha YZ125N1 Service Manual
OEM parts for Yamaha
http://mybikemanuals.com/yamaha/yamaha-yz-owners-manuals

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e


2003 Yamaha YZ... | 201 views | 0 helpful votes


Hi, Anonymous for this scenario you will need your service/owners manual if you can't find the first and best tool you ever bought for your Yamaha, despair not, for a mere $0 you can download another one. For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
How To Change Front Countershaft Sprocket On Dirt Bike
Yamaha YZ125N1 Service Manual
OEM parts for Yamaha
http://mybikemanuals.com/yamaha/yamaha-yz-owners-manuals
Yamaha YZ 125 02

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e


2003 Yamaha YZ... | 124 views | 0 helpful votes


Hi, Anonymous for this scenario you will need your service/owners manual if you can't find the first and best tool you ever bought for your Yamaha, despair not, for a mere $0 you can download another one. For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
Yamaha YZ125N1 Service Manual
OEM parts for Yamaha
http://mybikemanuals.com/yamaha/yamaha-yz-owners-manuals
Yamaha YZ 125 02
yz 125 tips and tricks YouTube

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e


2003 Yamaha YZ... | 64 views | 0 helpful votes


Hi, Anonymous for this scenario you will need your service/owners manual if you can't find the first and best tool you ever bought for your Yamaha, despair not, for a mere $0 you can download another one. For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
Yamaha YZ125 Float Stuck Help Needed
Carburetor Carb Leaking Gas How to Fix Repair it Motorcycle Honda DIY...
Yamaha YZ125N1 Service Manual
OEM parts for Yamaha
http://mybikemanuals.com/yamaha/yamaha-yz-owners-manuals

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e


2003 Yamaha YZ... | 230 views | 0 helpful votes


it should be just a bolt that goes through the base of kickstarter then wedge a screw driver into the slot to widen it and it should come off .but if you want to remove the shaft and all you will need to split the cases hope this helps

2003 Yamaha YZ... | 83 views | 0 helpful votes


How does the compression feel now that you have it cranking over again. Without the decompression lever pulled in it should be next to impossible to kick it over. also, is there any noise coming from the engine (knocking, etc.) when you got it to start again.

2003 Yamaha YZ... | 164 views | 0 helpful votes


Hi, Anonymous 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. 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 and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
Bike won start just backfires occasionally
01 FZ wont start after back fire FZ1OA Message Board
Yamaha YZ125N1 Service Manual
OEM parts for Yamaha
http://mybikemanuals.com/yamaha/yamaha-yz-owners-manuals

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e

2003 Yamaha YZ... | 294 views | 0 helpful votes


Hi, Anonymous for this scenario you will need your service/owners manual if you can't find the first and best tool you ever bought for your Yamaha, despair not, for a mere $0 you can download another one. For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
Dirt Rider Magazine
yz125 gas mix help Yamaha 2 Stroke
Yamaha YZ125T1 Owner Service Manual
OEM parts for Yamaha
http://mybikemanuals.com/yamaha/yamaha-yz-owners-manuals

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e

2003 Yamaha YZ... | 56 views | 0 helpful votes

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