Starter not engaging on 03 WR450

I have a wierd problem. My starter sounds like crap. Also, sometimes I hit the button and it sounds like the starter motor is just spinning. If I bump the engine over a bit (clutch out, in gear, bump forward) it will usually engage and start... but it still sounds like crap! Very noisy.... sounds like it is coming apart.

Anyone else have this happen?? Anyone know a fix?


My bro-in-law's '03 sounds just like that! He can sit there and push the button and sometimes it will grab and other times it won't. I've got a spare one-way clutch we're going to install to see if it cures it. We'll probably do that next weekend.

Thanks Dave,

I'd really appreciate the feedback.


Thats what mine was doing, it sounded really bad and just keep getting worse until it would only engage once and a while. New one way bearing cured my problem. Sounds like new again. You should be able undo the two bolts and take the cover off were the starter is and pop the idler gears out and see if you can spin the gears both ways. Mine still grab but sometimes you could spin it backwards. :thumbsup:

yes thats the one way bearing assembly :thumbsup:


SORRY for taking so long to get back with you! We had to wait on the correct flywheel puller to arrive and then I've been on vacation! :thumbsup:

We swapped out the one-way clutch assembly on my bro-in-law's 03 WR450 and we were SHOCKED at what we found. When we took the one-way assembly out it literally FELL APART!! Check out this photo of the one-way clutch:


It's difficult to see in the photo but the parts that made up the assembly are sheered and rough on certain sides and the spring that holds them all together was wadded up in the casing. We collected all the parts and confirmed that nothing fell into the motor while taking it out.

I would recommend installing the longer flywheel bolts while you have the assembly out. We didn't change ours out (didn't want to wait on the parts and we had a big ride the next day) but our bolts looked good so we reinstalled them. :devil:

The '04 one-way assembly (spare) I had is identical to the '03 part (they didn't change it in '04) and it completely resolved his starting issues. :awww:

Hey Dave great post! Do we have an issue with premature failure of these clutches or bearings? Mine still sounds normal and has always engaged and I dont want to think how many times I have used the e-start in the last 19 months. :thumbsup: Should I order a spare unit and prepare for failure in the near future? :devil:

I wouldn't keep a spare. It just so happened the TT'er I bought the starter upgrade parts from bought this one by mistake too and gave it to me free of charge. Lucky for my bro-in-law! A few months back his starter began clunking and intermittently engaging and we started looking at the system. Nothing strange and everything looked good. From what others had said here on TT the one-way clutch looked like it could be the issue and I just happened to have that spare.

Anyway, I think there have been a few on here that have had the same symptoms we've had but overall, I think they've been fairly reliable. I believe Yamaha expects this part to wear out because the manual says to inspect it occassionally and "replace as necessary." :devil: Yamaha's marketing department would call that CYA. :thumbsup:

Another possibility is that the cast aluminum side cover has cracked, and the idler gear is not engaging, as was the case on my bike. All in all, Yamaha kinda screwed the pooch on this starter system, IMHO. My bike is going up for sale next month....going orange!! (300 EXC) rekless :thumbsup:

Food for thought. Do you think this could be a side effect from trying to fix the bikes with the "woodriff" key issue.

What I mean is, one cause of the woodriff keys shearing was the engine would backfire, and the thrust from the backfire would shear the key. Well the factory fix is to Loctite the flywheel and torque flywheel nut on there super tight. This fixes the problem with the key sheering, but your bike is still going to backfire once in awhile. What is going to absorb that thrust, and prevent other parts in your bike from breaking?

Just wondering. I upgrade my 03 with 04 starter parts right away. In the 04 parts, the starter gear now has damper built into it which I assume is to absorb any thrust from a backfire.

There have been various other problems that resulted from the TSB having been done on some of the '03 models. However, mine and my bro-in-law's 03's (his is the one we replaced the one-way clutch on) haven't had the TSB performed because of other possible failures. I think his one-way clutch just decided to give up. :thumbsup:

Thats exactly what my bearing was like when I pulled it out, it just fell apart in my hand. I think it had to do with the TSB to, something had to take the kickbacks and it seems it was the one-way bearing.

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