Question about 2003 Yamaha YZ 125

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Remove magneto on crank - 2003 Yamaha YZ 125

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You will need a special puller. The tool is about $20 to $30 after market or $70 at the dealers parts department. Call around to find one. It will last a lifetime and will work on nearly all bikes, Honda, Yamaha, etc.. You just thread the tool into the magneto threads then turn the puller bolt very tight to put pressure on the end of the crankshaft then smack the puller bolt with a hammer. BINGO, the mag is free. Please rate my answer.

Posted on Mar 15, 2011


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Posted on Jan 02, 2017


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How to change a magneto on a riding lawn mower

Remove the end cover (where a rope starter is or would be). Remove the magneto attachment nut. Acquire a magneto puller. Attach it to the magneto, crank it until the magneto pops off. Find the little rectangular key (which might have popped off the shaft when the magneto popped off), and make sure it's seated in its little groove in the shaft. Place the new magneto on the shaft, install its attachment nut, crank it down.

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The voltage regulator may be bad, will need to unplug magneto and use multi meter and test magneto for voltage output on milliamp scale with the engine cranking, If voltage is present when cranking then the voltage regulator is bad , if no voltage then the pick-up coil and stator will need to be replaced.

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2001 yz250 the crank is lose when you pull the magneto

Check to make sure the magneto is tightened correctly on the crank first or remove it , if the crank has excessive play back and forth it may need new main crank bearings and or shim.

Jan 26, 2012 | Yamaha Motorcycles

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Big end bearing has disintegrated. What is the easiest way to strip the motor & remove crankshaft

If it's a 2-stroke, you'll need a crank puller and a case splitting tool to get this done, the crank is press fit into the magneto side bearing. If it's a 4-stroke, no special tools are required. Always pull the clutch side case off, leaving the transmission and crank in the magneto side. It's way easier to keep the transmission organized this way. Good luck!

Jun 09, 2011 | Yamaha Renegade 200 Motorcycles

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I am getting no spark at plug. Briggs model 31c707 motor. I have charged battery, adjusted valves, verified fuel line clear. Pull spark plug put into wire hold to motor and crank (no spark)

Hello, the next couple of things to check would be under the engine lid.

  1. Remove the screen over the air fan on the top of the fly wheel.
  2. Remove the 4 bolts securing the main lid and remove. Depending on the year of this engine it may have a secondary cover that Craftsman put on that will need to be removed first.
  3. When the lid is off you will see the magneto coil right above the spark plug; just follow the spark plug wire up to it.
  4. Use a wrench to see if the magnet on the fly wheel is strong. If the magnet is bad or really weak the flywheel will need to be replaced.
  5. Next check the magneto ground out wire. It will be a small black wire on the magneto. Unplug it then crank the engine. If the engine starts plug the wire back on the magneto and if it shuts down there is a short along the wire. It should only shut down or short out when the key is shut off. You will need to find the short if this is the problem.
  6. If the magnet is strong and the above test still fails to provide a spark then it is likely that the magneto is bad. You will need the rest of the model number; it will look something like: 31c707- # # # # - # # The part runs somewhere around $35.00 from Sears, but you might find it on-line cheaper.
  7. Replacing the magneto is pretty straight forward from there.
  8. Remove the old one and replace the old one adjusting it as far away from the flywheel as possible.
  9. Turn the flywheel until the magnet is directly across from the magneto.
  10. Put an ordinary business card between the magneto & the flywheel.
  11. Loosen the 2 screws that hold the magneto in place just enough for it to tighten up to hold the business card in place.
  12. Tighten the screws holding the magneto & rotate the flywheel to remove the business card.
  13. Test rotate the flywheel by hand a couple of full turns to ensure there is no contact with the magneto.
  14. Replace the small black wire, spark plug and spark plug wire, then test fire the engine.
  15. Shut the engine down and replace all the remaining parts in the reverse order as removed.
You should be good to go after this. If this was helpful please vote yes. Thank You!!

May 06, 2011 | Craftsman 17.5 hp 42 in. Deck Lawn Tractor...

1 Answer

Have a 1982 suzuki motorcycle gs1100gk starter turns magneto but is not cranking engine is this a keyway problem

Actually no this happened because the bolt holding the magneto on was not properly tighten to the correct torque a loose rotor will shear the key remove the rotor and inspect the key way remove what left and install a new set key and properly torque the bolt.

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2 Answers

I have a problem with my master craft lawn mower 2000 model. 4 stroke. 4.0 hp. There is no spark or current produced from magneto. What should I look for? I replaced the soft key on magneto and crankshaft.

I would remove the flywheel to gain access to your points and condensor. You might need to use a wheel puller to remove the flywheel. Once removed you will see another cover that houses your points and condensor. I would definately replace these no matter what. Be sure to set your new points to their proper gap...usually about .015 thousands. When setting gap make sure you are on one of the high sides of the cam. After installing turn crank shaft with cresent wrench adjusted around crank shaft and resting against the soft check to see that points are opening and closing properly. (Turn crank clock wise) Re-assemble all and give er a go!

Jul 28, 2009 | Garden

4 Answers

Poulan Pro 200 Leaf Blower won't start. I have installed a carb kit with no results. The spark plug was wet before the new kit---it continues to be wet. I have tried a replacement spark plug with no...

Alright, remember that 2-Stroke motors are meant to do 2 things:
Break down, then Frustrate you.

So, here we go: (Electrical)

Rotor Magnets, Magneto (ignition coil), Spark Plug Wire, Spark Plug, Spark Plug Ground (Cylinder Head).

In that order!

Check your "fire" from the Magneto:

1. Check your Kill Switch. In other words, leave everything normal, and unhook it. Did she start? Kill Switch it is! Kill Switch/Wire comes from the Magneto (single wire/ground) to the Switch itself. So check that wire AT the Magneto (Is it loose and grounding out? Is the Kill Switch grounding you out where it is, because of crud, junk, or because it is touching the block when it is not supposed to?)

2. Check your Spark Plug Wire. Easy, unook it from the plug, stick your finger in, give it a crank (non-MultiMeter way). Did you get shocked? Then it ain't your Plug Wire and Magneto!

With a Multi-/Volt Meter, simply hook her up, and check for juice WHEN you pull the rope. If you got juice, it ain't your Plug Wire or Magneto!

Checking Spark the "normal" way: Grab the Plug with a pair of insulated pliers, hold the plug end against the cylinder head, and pull your rope. Any Spark? What color?

3. STILL no fire. It leaves: Magneto and Plug Wire.
Luckily, they are both in the same place! Tear your blower down, and check to see if the Magneto has slipped out of place (gap is WAY out), or if the Plug Wire has worn to the point it is grounding you out. While you are there, check your Kill Switch wire, to see if she is grounding you out then and there.

4. STILL no fire. That means: Magneto Failing, or Magneto JUNK.
Buy another one, replace it! (Or steal one from another junk Blower/Weedeater. These things are fairly standard, and easy!)
Or, Bad Plug Wire. Meaning she has failed out on you.
Wait......that means: Replace your Magneto! Lucky the things are built together right?

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1 Answer

Husqvarna Riding Mower won't turn over

It could be a combination of things... it could be a loose earth lead from your ignitor pack or your timing could be out, check your key way that will be in the centre part of the magneto.. too see if its ok will need to remove the magneto to see the key way if its brocken it will not fire up and sometimes will back frie through carb if its bad enough, also check your gap between the ignitor pack and magneto should be around the .20 too .25mm by feeler guage...


Feb 24, 2009 | Husqvarna Garden

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