03 yz450, I have run out of experence, please help


11 replies to this topic
  • bejbis

Posted August 13, 2011 - 02:56 PM

#1

So, I have a 2003 yz450f, It ran great and i never had any problem kicking it over. then I decided to swap out the 4 speed for a 5 speed WR transmission.

I used all of the same internal parts with exception of the transmission. The crank, rod, piston, head, cams, valves, cam chain, carb and everything else are original. The only thing extra on the engine is a after-market stator and stator cover.

I have checked the bike for spark, and it is getting spark, I have no clue if it is getting spark in the correct place in relation to the crank angle. Im assuming this cannot be adjusted

it is getting fuel, as I can clearly smell fuel after a time or 15 of kicking.

The cam timing and valve clearance is spot on, I used a tube to find TDC of the piston through the spark plug hole to set the cam timing because i do not have a stator cover with stock timing marks. I am 90% positive this is set correctly.

When i kick the bike, it just kicks. I never ever get a pop or anything even when using starting fluid. I am stumped.

-Dan

  • dfeckel

Posted August 13, 2011 - 03:32 PM

#2

It certainly seems like the stator is the culprit, specifically whether the timing is correct. Do you have the stock stator handy? I would put that in, correctly timed, and see if it fixes the problem. If it does, try to determine the right way to time the aftermarket ignition before putting it back in.

  • grayracer513

Posted August 13, 2011 - 04:57 PM

#3

It's also extremely important to know if the aftermarket stator was made expressly for the YZ450, not the WR450, and was intended to provide ignition and lights, or lights only.

The WR electrical system and ignition CDI are fundamentally different from the YZF, and one will not work with the other.

  • bejbis

Posted August 13, 2011 - 06:34 PM

#4

It certainly seems like the stator is the culprit, specifically whether the timing is correct. Do you have the stock stator handy? I would put that in, correctly timed, and see if it fixes the problem. If it does, try to determine the right way to time the aftermarket ignition before putting it back in.


It's also extremely important to know if the aftermarket stator was made expressly for the YZ450, not the WR450, and was intended to provide ignition and lights, or lights only.

The WR electrical system and ignition CDI are fundamentally different from the YZF, and one will not work with the other.


dfeckel - I do not have the stock stator or cover, however, the flywheel is stock, and has a key in it to locate it on the crank. The crank has the trigger on it for when to tell the coil to fire. i don't know how i could possibly adjust this.

gray - I would assume that it was built for a YZ as it was installed and working on the bike for 2-3 years prior to me swapping the tranny. It is made by baja designs.

The bike is getting power from the stator when i kick it, the headlights turn on a bit, and if i pull the coil and sparkplug out i can physically see it sparking, so i am getting power from the stator, and a signal from the crank/ignition system.

please correct me if im wrong in my thinking...

  • bejbis

Posted August 13, 2011 - 08:13 PM

#5

Here are pictures of where my cams are when the motor is at TDC, with the aftermarket stator corver i find TDC when the piston is all the way at the top with a piece of rigid plastic stuck down the spark plug hole. Just saying, there are 13 pins between 12 o'clock marks.

Intake cam.
Posted Image

Exhaust cam.
Posted Image

Both cams.
Posted Image

Rear of cams.
Posted Image

  • grayracer513

Posted August 13, 2011 - 08:35 PM

#6

How is the stator indexed to the crank? What fixes it in the correctly timed position?

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  • bejbis

Posted August 13, 2011 - 09:57 PM

#7

How is the stator indexed to the crank? What fixes it in the correctly timed position?


Maybe im missing something? the aftermarket stator just goes on the crank shaft, on the outside of the stock flywheel/stator/magneto(?). The stock flywheel that has the timing marks on it is still there, i just have no way of indexing it as the aftermarket stator cover has no timing hole.

The aftermarket stator dose not care where its at in relation to the rotation of the crank, as its just there for power right?

the stock flywheel/stator/magneto that picks up the trigger for the coil is still there, and is indexed on the crank by the key-way on the crank.

here is a picture of the aftermarket stator cover.

Posted Image

  • grayracer513

Posted August 14, 2011 - 08:13 AM

#8

Then the external stator has nothing to do with your problem unless it's been hooked into the ignition somewhere.

At this point, you should check the stock flywheel to see if it is correctly indexed on the crank. If it's timed right, you're getting spark, and there's no possibility that the plug is fouling under pressure, your problem is apt to be in the carb, probably a blocked pilot.

  • bejbis

Posted August 14, 2011 - 09:09 AM

#9

Here is how the flywheel is indexed on the crank. the screwdriver point at 12'oclock in the first picture, pointing where the last I to the right is where it has I H I.

I would tend to believe carb, but it ran great before i tore it apart, and even with starter fluid is isnt even trying to make a pop. I also removed the bowl and checked all the jets, they are all clean and i can see through all of them just fine.

Posted Image

Posted Image

Edited by bejbis, August 14, 2011 - 09:45 AM.


  • grayracer513

Posted August 14, 2011 - 10:07 AM

#10

Hopefully, the second picture was not taken at TDC, because I can see the trigger lug on the inner flywheel is near 6:00 instead of passing under the trigger coil as it should be. I see no screwdriver point.

Position the engine at TDC and check that the I mark to the right of the H is aligned with the cylinder center line.

  • bejbis

Posted August 14, 2011 - 04:24 PM

#11

Hopefully, the second picture was not taken at TDC, because I can see the trigger lug on the inner flywheel is near 6:00 instead of passing under the trigger coil as it should be. I see no screwdriver point.

Position the engine at TDC and check that the I mark to the right of the H is aligned with the cylinder center line.



I have edited picture on previous post to show where the I that is to the right of the H is on the flywheel.

Yes, all pictures were taken when the piston was at the top of its throw. For some reason i am drawing a blank, but im pretty sure when looking at the flywheel in the picture is spins counter clockwise when the engine is running. If so, the raised portion on the flywheel that triggers the coil is at the end of the pickup when the piston is at TDC.

Is my crank on there incorrectly? If it was on there to where the beginning of that raised portion hits the trigger, the I mark would be inline with the transmission and not the cylinder.

  • grayracer513

Posted August 14, 2011 - 05:02 PM

#12

... the raised portion on the flywheel that triggers the coil is at the end of the pickup when the piston is at TDC.

That would be correct.

So, then, time to look into the fuel system.





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