Question about 2001 Yamaha YZ 426 F

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When choke is off wont idle

When starting my yz426f i pull the cold start choke bike starts after a few times but it doesnt rev high as my mates one it sounds like a normal bike idling and when i close the cold start choke bike just cuts off , i thinks idle is set wrong ( very low) is there any method to set it right?? i normaly have to ride the bike all the time with choke open

Posted by Anonymous on


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  • 41,919 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

Posted on Aug 02, 2016


6 Suggested Answers

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Posted on Jan 02, 2017

  • 261 Answers

SOURCE: motor bike wont rev above idle weth choke on

This to me sounds like you need a carb cleaning. If you have let the bike sit for an extended time the carberators maybe clogged or gummed up. This has to do with the new gas that is out there now. It is cheap and with the introduction of Ethanol alcohol now it is even worse on being stable for long periods of time. I have seen fuel go bad in as little as 3 weeks.. One quick check you can do is open you fuel tank and smell the fuel. IF it smells like varnish it is probably bad. You can drain the tank and add new fuel and that should solve your problem. Keep in mind, that the carbs need to be drained as well to get the old fuel out of there also. Make sure you have a battery charger going when you start crankin that puppy, because you will need lots of extra juice to get that baby to fire up. If it is starting now and runs on choke, that means your idle jets are clogged. Best repair is to remove carbs and clean idle jet. Unless it is fuel injected.
Let me know how that goes and we can proceed from this point. I am a certified mechanic from MMI as well as a HDTV GURU. Smiles. have a good one.

Posted on Dec 07, 2008

  • 14 Answers

SOURCE: bike idles, but with a little throttle it jumps to high rev and wont come back down to idle

You need to oil your cables first....They make a gadget to help you do clamps around the end of the cable, and you spray oil into a provided hole for a spray nozzle tube...Then see if the cables are unstuck by turning the throttle grip back and forth for awhile....start it and see if that helped....if not you may need to replace the cable(s)...I doubt that the slide in the carb is hanging up...or valve.If this doesn't work notify me.

Posted on May 10, 2009

  • 375 Answers

SOURCE: My 9 month old Yamaha YZF-R125 has been cutting

Sounds like you have either got water in the system or poor connections.
You can use something like dielectric grease on each connector. It is a bit of a pain having to open and close each connector on your bike, but once you've done it, you shouldn't need to do it again for a long, long time.

Posted on Jun 29, 2009

  • 4525 Answers

SOURCE: Engine cuts out with clutch engaged.

is your bjke water cooled could have aproblem with that-its gettin hot-if air cooled carb may neede cleaning. the clutch is ok but indicates to me that that carb needs a low speed jet adjust also-do u have a clymer manual!!

Posted on Aug 04, 2009

  • 3567 Answers

SOURCE: Yamaha DT 125 1986 - High Revs when idling

There have an air leak between the carb and the cylinder and/or the head and cylinder. Old hard / cracked rubber fittings and O rings are usually the problem. When extra air gets into the system it leans the fuel mix and the high idle is the result. It also means the engine runs hotter. Also, cracked or broken reeds can be a source.

Posted on Aug 10, 2009

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2004 Honda CR 125 R very high idle

Hi, Anonymous and the usual suspects are:
1. Throttle cables improperly adjusted, pinched or need lubrication.
2. Idle adjusting screw needs to be backed off.
4. Air fuel mixture adjusted too lean start with 2 full turns.
5. Intake system air leak.
6. Fast idle choke ramp is not releasing.
7. Broken throttle return spring.
8. Damaged diaphragm or slide.
9. Faulty MAP, TPS, ATS, O2, sensors or wiring/connector.
10. Multiple carburetors not in sync.
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.
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Apr 17, 2014 | 2004 Honda CR 125 R

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Sounds like the idle is out of adjustment. There should be a knob with a phillips type screw on a cable that can be reached on the left side of the bike. Turn it counter clockwise to lower the idle.

Jul 27, 2013 | kawasaki ZX-6R Ninja Motorcycles

1 Answer

YZ426 idle probs

Hi, Mike and the usual suspects are:
1. Throttle cables improperly adjusted or pinched.
2. Idle adjusting screw needs to be backed off.
4. Air fuel mixture adjusted too lean start with 2 full turns.
5. Intake system air leak.
6. Fast idle choke ramp is not releasing.
7. Broken throttle return spring.
8. Damaged diaphragm or slide.
9. Faulty MAP, TPS, ATS, O2, sensors or wiring/connector
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.
Other yz426 idle problem
YZ426 Hanging idle Intake Jetting Fuel Injection
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

May 25, 2012 | 2002 Yamaha YZ 426 F

2 Answers

I have a 2006 GSX600F Katana with 500 miles on it from new and am looking for assistance to fix the problems of idle speed increasing when the bike gets warm, flat throttle response at low revs and RPM's...

hello lloyd...... definitely pull the carbs and rebuild them. Since you did everything else right, this alone should fix the problem. Joe
Thanks for choosing Fixya!

Dec 31, 2010 | Suzuki GSX 600 F (Katana Motorcycles

1 Answer

Motor wont rev up when starting cold with choke on trys to run on idle but will not rev up

the motor wont rev high on choke.the motor is suppose to fire once on choke. then turn the choke off.pull the start cord and the motor should start and run.check that the throttle conrol is on full. it should run fine.

Dec 26, 2010 | Honda 8 HP Engine

1 Answer

Bike wont kick start or idle , it will coast

first drain the carby, then set your air mixture screw 2 turns out, from the fully turned in position. The starting proceedure is as follows, when the engine is COLD, turn on fuel, pull on the choke fully, and kick the engine over. DO NOT use any throttle, when the engine is cold, and the choke is on. Remember Choke on, NO throttle.
When warm, no choke, and a little throttle when kicking.

May 12, 2010 | 2003 kawasaki KX 125

1 Answer

Last time I STARTED MY VSTAR 1100 I CHOKED IT FOR 10 SECONDS ON HIGH THEN MOVED TO MEDIUM CHOKE FOR 4 THEN TOOK OFF AT NO CHOKE. 2 WEEKS LATER. I started up bike Choke on high bike barely wanted to idle...

Sounds like your flooding it out with the choke out. Try the next time you go to start the bike when it's cold with the choke out and when it starts push the choke all the way in and keep it running with the throtle. If it runs better after doing this then your flooding it on start up. Use 1/2 choke to start cold and see what it does. Good Luck

Sep 29, 2009 | 2001 Yamaha V Star Classic

3 Answers

My motor wont start..!

  1. The carb has 2 choke knobs,red and black one,black for cold start and red for hot start,I found on my 426 that by pulling the black one every time I try to start the bike,the bike starts hot or cold.When it started press the choke knob back.
  2. A dirty air filter will also make the bike difficult to start.
  3. Do not open the throttle even a bit whilst kicking it,the carb tends to flood very easily and then you are going to kick the bike for ever and ever.
  4. The exhaust turning red hot I'd suggest you get the carburator's jetting checked out,it can be because your feul/air mixture is not right and this could also be a factor in your starting problem,but another reason can also be when the bikes stands still whilst idling or even being revd whilst not in motion the engine tends to get very hot very quickly,the bike does not have a electric fan blowing threw the radiator,and if you did not know your exaust system removes between 60-70% of your engines heat,so it will turn red hot if your are not riding so the cold wind can blow over the exhaust and threw the radiator.
  5. You say you get good spark,where did you test it?Did you check the spark plug itself,or only the sparkplug lead,I find the 426 to be very hard on spark plugs,when I find my 426 difficult to start the first thing I change is the spark plug and it solved my problem many times.
  6. You also mentioned you have feul "to" carb but do you have feul - carb to engine.
  7. How does the compresion feel when kicking the kickstarter,any lack in compresion could indicate a sticky valve in the open position,the unexperianced rider will not kickstart this bike due to the amense compression these bikes have (Ratio 12.1).
Just a few suggestions I hope one works for you.

Nov 14, 2008 | 2002 Yamaha YZ 426 F

1 Answer

High idle or no start

headlight front signals some fuses; cleaned carbs; repainted. When I received it it was hard to start. Had to kick it into submission and the choke plunger would not stay out. I've since tightened up the choke plunger friction nut and reclamped it towards the carbs (after cleaning the carbs). Problem #1: I can't remember exactly how the clamp is supposed to be positioned on the bottom of the cable: on the metal cylinder? On the indented part of it? And I have a rubber boot on the carb end of it; this boot just slides around and doesn't seem to even fit over the indented end of the metal cylinder. Problem #2: High idle or no start problem: The only way I can get the bike to start cold is to unclamp the cable (tank off) and yank on the cable. As the bike warms up I let the cable go and clamp it down at the point where the choke plate/linkage/butterfly/whatever is completely closed at the carb and no rise in idle is happening. Then I have a nice idle at 1200 +- 100rpm. While the bike starts right up when hot using this setup, it won't start cold unless I go through the rigamarole again. If I clamp the cable in a position so that it will start cold next time, then once the bike warms up and I turn off the choke, the idle falls at 2500rpm. The choke plate is definitely still open at the carb. It almost seems like the cable is wrong for the bike. I seem to need a larger variance in cable length between choke-on and choke-off. I wouldn't be surprised if the previous owners did something funky with aftermarket parts. Help? ,sound like u got both---send it to the mechanic,,,

Nov 10, 2008 | 2005 Beta Alp 4.0

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