Starting problem WR450 07 with Video

My bike has been slowly getting harder to start on the button, but now it will only start on the kick. As you can see on the video the starter relay is making a bad fast clicking noise.

The battery is fully charged & also tried another full battery so its not that, tried another starter relay so its not that.

Do I need a new starter motor ? Is there a test I can perform before I buy a new one ?

Ive been having this same exact problem with my 08, just haven't gotten around to checking it out. Hopefully someone can chime in and help out, with all this snow we've been getting hammered with I haven't seen my bike since November!

mine was acting the same way. I bought a new battery and the problem went away. Now..... I was at a race last weekend and got the nasty scream sound comming from my starter. I pulled out the starter and everything checked out by the manual so i put it all together and lubed the starter at the end where the scream was comming from. Now the I have the same problem. Ill be watchin your post!

WR250F's and WR450F's need a solid 12v to run the ECU properly. If the bike isn't starting on the button, put a charge on it and see if that works. If the battery won't hold a charge, replace the battery. The worst thing to do it let the battery run down as this causes it to lose capacity more than anything. From my experience, the Yuasa battery that comes with them is good for a year, maybe two. Some folks get longer runs of out them. However, the vibration from riding is hard on the plates and they often lose capacity from physical damage (from riding) as well as sulfation damage if they sit for say a month or more (like during the winter...) and self-discharge without the bike being run or the battery float-charged. That $30 battery tender is your friend and can save you at least that much in not having to replace the battery as often. Anyway, I'm asuming that you're not using a battery tender, I could be wrong.

The starter actuators do tend to fail on these bikes. It sucks, but that has nothing to do with the low-voltage buzz in the video.

If the battery is fully charged and you only get a few cranks out of the battery, replace the battery. It will still need a couple of hours of charging after being activated before use.

A friend of mine has a 250 , would the starter motors be the same ? As I will try this next

I'm not saying that this mod should be used to cure an underlying problem but........When using the estart it only fires on every third stroke. Do a search on the blue/white wire mod in this forum.

Basically there is a blue/white wire at the CDI box that can be disconnected to make the estart fire on every stroke. This is DIFFERENT than the grey wire mod. :thumbsup:

I heard the e start only firing on the 3rd stroke was a myth, Cant remember who disputed it, perhaps one of the moderators, not sure though.

Join Date: Oct 2006

Location: Virginia

Age: 53

Posts: 22,831


Originally Posted by tribalbc

On the estart it only fires on I think it's every third stroke, a couple strokes to build compression. Do a search on the blue/white wire mod in this forum.

Basically there is a blue/white wire at the CDI box that can be disconnected to make the estart fire on every stroke. This is DIFFERENT than the grey wire mod.

Not correct.

The spark occurs every time the engine is at TDC. The blue wire tells the CDI if the bike is in neutral or in gear. It advances the timing a tiny bit when in gear to cause the idle to be stronger to compensate for the drag of the clutch. I have found on a properly maintained and setup bike, there is no advantage to removing the blue wire. All bikes I work on start instantly, barely a rev with the E-button and not even a full kick with the kicker.


posted by moderator william on thread 931264 bout half way down the page...

dont know if hes right however, but this is what I had read making me wonder if this mod works, the moderators are usually up to speed on things like that.

I'm following you on this, but if you read further into the post....

Post No. 64, page 7 By William1.


Sorry it took so long for me to get back to you Guy. Being my WR always starts instantaneously (except when it is colder than a thing) and the Sky Blue wire made no difference to me, I was skeptical, as my previous posts oozed of.

Well, I got off my butt... again, and went and did the mod to my WR250. It does seem to start faster. I traced the wiring diagrams as you told me to Guy and I understand the interface. I also discovered that is the pin touches ground, the starter motor will spin!

So I apologize for my previous bald faced lies!

Next question (at least for me) is why did/would Yamaha do this? Is it to give the engine a chance to suck some fuel in the carb passages ways before attempting to fire off? This seems plausible until you wonder if that is the goal, then why even bother to kill the spark, just let the engine crank until the gods of good fuel mixture give their blessing and go. Is there a perceived issue of backfiring? Is there a desire for the engine to have some momentum until the spark potentially kicks back?

Here is a picture of the plug and the wire removed and sealed. You will notice it was right next to the infamous Gray wire (mine is on a switch, that is why the wire is still there) on my wr250. I have a few extra blank plugs for the socket so I put one here the wire was and used a second one to cap off the other end of the shrink wrap. End quote

Theres maybe something in after all............


The sky-blue wire mod sets the spark advance map to be the same as a YZ - i.e. the bike has the same advance in neutral as it does in-gear. The primary benefit for this is that when you tune the pilot circuit, you can set the optimum mixture for what the bike "should be" burning when in gear. This is because with the mod done, the RPMs in neutral increase slightly (due to timing effects in the engine), increasing carb vacuum and pilot circuit fuel flow - thus the a/f mixture at idle in neutral will also be the a/f mixture at idle when in-gear and the clutch pulled. If the bike is left stock, then the timing is still retarded a bit when you peak the idle speed with the fuelscrew and when in-gear, the mixture will be slightly leaner than it should be if it were tuned correctly; the wrong a/f mix = less power, so this mod really should be done. It helps with the off-idle bog as well. :thumbsup:

I suspect that Yamaha did this to: 1) meet CARB requirements in CA since they bother to green-sticker the bike, and 2) to make the bike more rider-friendly by reducing hanging idles through retarding timing and forcing the idle RPM to drop when in neutral.

Fwiw, the ACV mod should also be done to take advantage of the sky-blue wire mod. There's no sense remapping the neutral timing if the a/f mixture is still unstable because the ACV is affecting (enrichening) the carb as vacuum changes. :lol:

Ok... thanks.. I stand educated... perhaps I should have read all of the thread that DG posted... thats what I get for surfing TT at

A couple of things to check:

I had one of the magnets come unglued inside a TTR-50 starter - so it was actually just producing half of the starter torque and draining the battery, until the magnet shifted and locked it up. It will stick to the starter housing and be "out of time." Glued it back in with epoxy and works fine.

Granted, the TTR-50 starter is on the bottom of the motor and may have been broken loose by a case hit... unlikely with the WR but still plausible.

The wires from the battery to the starter can get corroded/frayed and go bad. Check your voltage at the starter post while cranking.

Don't assume a battery is good unless you had someone load test it.

Also - the starter motor brushes are replaceable for $16. One of those could be bad.

Ive been told its the battery ??? I got the battery checked & they told me a cell had gone , but I did try a mates battery that I know thats good (But it is off a 250) but still makes the same noise .

I will get a brand new battery & see what happens then !

check your starter motor brushes, I had this same problem , new battery - no help. the brushes were worn to the limits and not making contact with the starter motor commutator. Make sure you mark the position of the end caps in relation to the motor housing before dissassembly - put it together wrong and the motor turns backwards.


Finally got the replacement battery (Dynovolt YTZ7S 6ah) & starts ! But doesnt start on TDC ? maybe this is why my battery of only 3 months old ended up having a dead cell (Buckled cell maybe ?)

Certainly needs a man enough battery as I tried a friends brand new 4ah battery & got the same clicking noise.

Below is what happens with the Brand new battery

What now ? This is was happened before the battery went dead on me before ?

Edited by mightymart
extra details

Did you charge the battery for at least 2 hours after activating it?

Did you charge the battery for at least 2 hours after activating it?


After looking in the manual Ive seen on page 4-29 Decompression system:

.Check decompressor cam moves smoothly

.Check that the decompressor lever pin projects from the camshaft.......

This maybe the problem ???

Im good with general maintenance etc , but this is taking the engine apart :smirk: Is this a job for a Pro to check ?

Checking the decomp system isn't that hard.


If you're getting a clicking noise in your starter, you simply aren't getting enough voltage to keep the relay engaged. Check the cables for corrosion and connections for tightness. Maybe the starter needs to be rebuilt.

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