20 Most Recent 2001 Yamaha YZ 426 F Questions & Answers


Hi, Anonymous and the usual suspects are:
1. Fuel cap or fuel tank is not venting properly.
2. Fuel filter clogged.
3. Fuel line pinched or kinked.
4. Float needle and seat sticking.
5. Float level too low.
6. Carburetor bowl vent line clogged/blocked/pinched.
7. Idle adjusting screw set too low.
8. Air/fuel mixture screw set too lean.
9. Idle port, transfer ports, slow air jet clogged.
10. Slow fuel jet clogged.
11. Faulty fuel pump.
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.
YZ426 won idle without choke Intake Jetting Fuel Injection
YZ426F Won Run Choke 4Strokes com
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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

2001 Yamaha YZ... | Answered on Nov 29, 2019


Hi, Anonymous and the usual suspects are:
1. Engine oil level and SAE weight are too low or not circulating.
2. Insufficient or blocked air flow over the engine.
3. Heavy combustion chamber carbon deposits.
4. Ignition timing retarded due to faulty MAP, CKP, or CMP sensor.
5. Carburetor jetted too lean.
6. Leaking intake or exhaust valve.
7. Water coolant old or low change every two years.
8. Water pump failure.
9. Radiator clogged, cap loose or malfunctioning.
10. Radiator fans not coming on.
11. Clutch slipping, brakes dragging, heavy load, towing a trailer etc.
12. Idling too long without moving.
13. For constant hot weather temperatures, mountain, or desert riding conditions consider adding an oil cooler and or cylinder head cooler.
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.
Help 01 YZ426 overheats at idle YZ 400 426 450
PLEASE HELP Having engine problems with wr stator on my yz 426 YZ 400 426...
Yamaha YZ426F LC 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

2001 Yamaha YZ... | Answered on Oct 21, 2016


Hi, Eweber2005 for this situation I would call 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 please click on the links below. Good luck and have a nice day.
Dubach yz426 wet sump YZ 400 426 450
wet sump YZ426
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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

2001 Yamaha YZ... | Answered on Aug 08, 2016


Hi, Snapper631 it should be noted that your performance issues are not electrical ie. faulty charging system, battery condition, and connections etc. If your fuel system (gas tank, filters, fuel valve and carburetor) is contaminated with ethanol sludge, varnish, rust, dirt, water etc. or your bike has been sitting for months or years without running these components must be "PROPERLY" cleaned and reassembled "CORRECTLY" before any adjustments can be made. Tuning your carburetor is fairly simple once you understand the basic principals. You engine is a simple airbox sucking air in and blowing it out, it is finely tuned at the factory for maximum performance once you upset that delicate balance by changing air filters, camshafts or exhaust systems your performance may go down the and the engine may run poorly, you need to compensate the air-fuel mixture in the carburetors in order for the engine to run smoothly and at peak performance. If you are running multi carburetors you need to sync them first and make sure your air cleaner element is clean and dry for paper elements or lightly oiled for foam and meshed elements and properly installed. Here is how and where you compensate trouble: "TIP" if your engine "BOGS" your not getting enough fuel.
1. Closed to 1/8 throttle is managed by the air screw and pilot/slow jet.
2. 1/8 to 1/4 throttle is managed by the air-screw, pilot/slow jet, and throttle slide.
3. 1/4 to 1/2 throttle is managed by the throttle slide and jet needle.
4. 1/2 to 3/4 throttle is managed by the jet needle, needle jet, main jet, and air jet.
5. 3/4 to wide open throttle is managed by the main jet and air jet.
6. Wide open throttle is managed by the main jet.
If you are running lean, spark plug electrode color is white, engine runs hot and feels like it is starving for fuel you need to go up on the jet size or move the c-clip down one notch. If you are running rich, spark plug color is black or dark gray, engine runs cool, and bogs down when accelerating you need to go down on jet size or move the c-clip up one notch. When your carburetor is properly tuned for maximum performance your spark plug electrode will be a light tan color like coffee with cream. If you prefer fuel economy over performance you can go down on main jet sizes until a satisfactory level of lower performance is acceptable versus MPH, your spark plug color will be whiter and your engine will run warmer. These tuning adjustments will only make improvements if your intake and exhaust system have no air leaks or sealing issues and the entire electrical system is in proper working order and you have no mechanical issues. For more information about your issue and valuable "FREE" downloads that you will need please click on the websites below. Good luck and have nice a day.
YZ426 Carb Adjustment
How To 4 Stroke MX Fuel Screw Adjustment YZF CRF KXF RMZ FCR Part 1 of 2
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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


2001 Yamaha YZ... | Answered on Aug 08, 2016


Hi, Mrhoads62 for this situation I would call 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 please click on the links below. Good luck and have a nice day.
wr yz stator swap help YZ 400 426 450
YZ426 Lighting Stator Issues
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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

2001 Yamaha YZ... | Answered on Aug 08, 2016


Hi, Brennanhales it should be noted that your performance issues are not electrical ie. faulty charging system, battery condition, and connections etc. If your fuel system (gas tank, filters, fuel valve and carburetor) is contaminated with ethanol sludge, varnish, rust, dirt, water etc. or your bike has been sitting for months or years without running these components must be "PROPERLY" cleaned and reassembled "CORRECTLY" before any adjustments can be made. Tuning your carburetor is fairly simple once you understand the basic principals. You engine is a simple airbox sucking air in and blowing it out, it is finely tuned at the factory for maximum performance once you upset that delicate balance by changing air filters, camshafts or exhaust systems your performance may go down the and the engine may run poorly, you need to compensate the air-fuel mixture in the carburetors in order for the engine to run smoothly and at peak performance. If you are running multi carburetors you need to sync them first and make sure your air cleaner element is clean and dry for paper elements or lightly oiled for foam and meshed elements and properly installed. Here is how and where you compensate trouble: "TIP" if your engine "BOGS" your not getting enough fuel.
1. Closed to 1/8 throttle is managed by the air screw and pilot/slow jet.
2. 1/8 to 1/4 throttle is managed by the air-screw, pilot/slow jet, and throttle slide.
3. 1/4 to 1/2 throttle is managed by the throttle slide and jet needle.
4. 1/2 to 3/4 throttle is managed by the jet needle, needle jet, main jet, and air jet.
5. 3/4 to wide open throttle is managed by the main jet and air jet.
6. Wide open throttle is managed by the main jet.
If you are running lean, spark plug electrode color is white, engine runs hot and feels like it is starving for fuel you need to go up on the jet size or move the c-clip down one notch. If you are running rich, spark plug color is black or dark gray, engine runs cool, and bogs down when accelerating you need to go down on jet size or move the c-clip up one notch. When your carburetor is properly tuned for maximum performance your spark plug electrode will be a light tan color like coffee with cream. If you prefer fuel economy over performance you can go down on main jet sizes until a satisfactory level of lower performance is acceptable versus MPH, your spark plug color will be whiter and your engine will run warmer. These tuning adjustments will only make improvements if your intake and exhaust system have no air leaks or sealing issues and the entire electrical system is in proper working order and you have no mechanical issues. For more information about your issue and valuable "FREE" downloads that you will need please click on the websites below. Good luck and have nice a day.
Carb tuning on yz250f swivel technique
How To 4 Stroke MX Fuel Screw Adjustment YZF CRF KXF RMZ FCR Part 1 of 2
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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



2001 Yamaha YZ... | Answered on Aug 08, 2016


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.
Best coolant and mix YZ426 YZ 400 426 450
http://www.r1-forum.com/forums/2-general-motorcycle-discussions/86252-what-kind-antifreeze-should-you-run-r1-any-motorcycle.html
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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

2001 Yamaha YZ... | Answered on Aug 08, 2016


Hi, R6ridegirl after careful deliberation 4 out 5 Yamaha Gods give this one a thumbs up, but just to be on the safe side you should give your local dealer's parts/service department a call to confirm. For more information about your question and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3
What are the top 5 mods to get for yz426f YZ 400 426 450
Yamaha YZ 426 FN 01

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

2001 Yamaha YZ... | Answered on Aug 08, 2016


Hi, Ccarlson426 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.
Head torque spec or angle torque YZ 400 426 450
2011 yz450f rear axle nut torque spec
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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

2001 Yamaha YZ... | Answered on Aug 08, 2016


Hi, Crazypaintba after careful deliberation 4 out 5 Yamaha Gods give this one a thumbs up, but just to be on the safe side you should give your local dealer's parts/service department a call to confirm. For more information about your question and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3
What are the top 5 mods to get for yz426f YZ 400 426 450
Yamaha YZ 426 FN 01

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

2001 Yamaha YZ... | Answered on Aug 08, 2016


Hi, Jtloya 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.
Piston ring gap position during assembling WR 400 426 450
http://www.wiseco.com/PDFs/Manuals/RingEndGap.pdf
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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

2001 Yamaha YZ... | Answered on Aug 04, 2016


Hi, Rob and the usual suspects are:
1. Fuel tank empty.
2. Fuel supply valve/petcock turned off.
3. Fouled spark plugs.
4. Engine flooded as a result of overuse of the enricher.
5. Vacuum hose to the fuel supply valve/petcock disconnected, broken, cracked, or pinched.
6. Fuel valve/petcock or filter clogged.
7. Fuel line to carburetor or throttle body pinched or kinked.
8. Carburetor float stuck.
9. Fuel injectors clogged.
10. Severely discharged or damaged battery, you need 12.5 volts or better and be able to pass a load test if necessary.
11. 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.
12. Loose or corroded wire connection at the coil, battery or plug between ignition sensor and module.
Spark plug cables in bad condition and shorting, cable connections loose, or connected to the wrong cylinders.
13. Ignition timing incorrect due to a faulty ignition coil, ignition module or sensors (MAP, CMP, CKP, O2, TPS, ETP, IAC,or BAS).
14. Faulty neutral, clutch lever, or kickstand safety switch.
15. Faulty fuel pump or fuse or relay.
16. Faulty CDI box if applicable.
17. Tilt sensor needs a reset.
18. Security system not disarming alarm needs a reset.
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.
YZ426f WON START YZ 400 426 450
YZ426F Will not start
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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

2001 Yamaha YZ... | Answered on Aug 04, 2016


Hi, Alice35 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.
01 yz 426 fuel mixture screw on the carb HELP YZ 400 426 450
Fuel Screw Replacement Video
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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


2001 Yamaha YZ... | Answered on Aug 04, 2016


Hi, Brad 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.
2001 yamaha yz426f tips
Replacing Air Filter on 2008 YAMAHA WR450F Yz450f mod
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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


2001 Yamaha YZ... | Answered on Aug 04, 2016


Hi, Josh 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.
2001 yz426f backfiring
2002 YZ426 Backfiring Issue YZ 400 426 450
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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

2001 Yamaha YZ... | Answered on Aug 04, 2016


Hi, Anonymous a YZ is a motocross bike designed to run flat out that being said if you are strolling down some scenic trail at a slow pace or letting the bike idle for a few minutes your header pipe will turn cherry red, why you ask? It is not a street bike, it is designed for competition and weight is a major factor all necessary components are of the smallest and lightest design necessary to maintain performance under extreme conditions ie. small radiator and inside frame oil reservoir that doesn't get cooled, the majority of your riding needs to be at high speed. 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.
02 YZ426F Header Pipe Glows Red 4Strokes com
2002 Yz426f Header Pipe Turns Red YZ 400 426 450
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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

2001 Yamaha YZ... | Answered on Aug 04, 2016


Hi, Bmalechek1 and the usual suspects are:
1. Spark plugs in bad condition or have an improper gap or are partially fouled.
2. Spark plug cables in bad condition.
3. Battery damaged or nearly discharged, should have 12.5 volts.
4. 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.
5. Throttle controls not adjusted correctly.
6. Water or dirt in the fuel system.
7. Water or dirt in the carburetor.
8. Intake air leak.
9. Fuel tank vent hose and vapor valve plugged, or fuel line closed off, restricting fuel flow.
10. Enricher valve inoperative.
11. Engine lubricant to heavy (winter operation).
12. Ignition is not functioning properly (possible sensor failure).
13. Faulty ignition coil.
14. Valves sticking.
For more information about your issue and valuable "FREE" downloads that you will need please visit the websites below. Good luck and have a nice day.
Dirt Rider Magazine
How to Start YZ426F Easily
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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


2001 Yamaha YZ... | Answered on Aug 04, 2016


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.
yz426f oil change
How To Change Engine Oil
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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


2001 Yamaha YZ... | Answered on Aug 04, 2016


Hi, Greengobl837for this situation I would call 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 please click on the links below. Good luck and have a nice day.
Yz426f Plastics YZ 400 426 450
using YZF plastics on WR426 WR 400 426 450
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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

2001 Yamaha YZ... | Answered on Aug 03, 2016


Hi, Missingpap 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
How much oil does YZ426 hold YZ 400 426 450
How To Change Engine Oil
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

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


2001 Yamaha YZ... | Answered on Aug 03, 2016

Not finding what you are looking for?
2001 Yamaha YZ 426 F Logo

139 questions posted

Ask a Question

Usually answered in minutes!

Popular Products

Top Yamaha Experts

Steve Sweetleaf
Steve Sweetleaf

Level 3 Expert

1176 Answers

Paul Ellermets

Level 1 Expert

6 Answers

Neil Lancaster
Neil Lancaster

Level 1 Expert

14 Answers

Are you a Yamaha Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

View Most Popular

YZ 426 F Yamaha

  • YZ 426 F Yamaha

Most Popular Question

slight bog under acceleration

  • Motorcycles
Loading...