03 "woodruff"mod

Ok Ive read a couple hundred threads now pertaining to this modification, I almost think I could do it in my sleep and I no way qualify as a mechanic. I'm just curious about this because I just bought my 03 a couple months ago, I talked to the previous owner the other day and he told me he never had this mod done. Seeing as this bike is an "03" and now over 2 yrs old with many hours on it (starts on 2 or 3 kicks, cold starting) every time and then fires right up every time with the e-start is it necessary to still do this mod, or is it possibly a later released 03 and not needed. Is this a problem that would have occurred fairly soon after purchasing the bike. The specs to my bike are listed in a previous post. Thanks, I'm hoping to squash my worries about this from the answers I receive, I either will quit worrying about it or get the parts and make the mod, just don't want to waste my money on something that isn't needed. Thanks.

My advice is to do what it takes for you to feel comfortable. If that means lapping and locktiting the flywheel and/or upgrading the starter parts, then do it.

I tore my 03 down after taking delivery and found the flywheel taper did not match the crankshaft taper. Not even close. Looked like a failure waiting to happen. So I lapped it to match, remounted it with locktite and have gone 7500 miles of hard off roading with absolutely no problem. Mine bike backfires occansionally, sometimes hard, sometimes while cranking the starter...no problems. Others, as you have read, have had differing experiences and applied different fixes. I can only speak for myself.

So my 2 cents worth (and 2 cents ain't worth much these days) is that if your bike has a lot of miles with no issues, its probably just fine. Stop worrying about it. But as always, YMMV.

How was that for totally useless advice? :applause:

I wouldn't do the loctite, but it is worthwile to do the 04 starter gears upgrade, and I'd inspect the sidecover and gears before ordering anything. I found a broken idler axle boss and a missing tooth from the inner idler gear a year(~1100 miles) after I bought mine. The dealer did the "woodruff key mod" before I took possession.Prob'ly wouldn't hurt to check and lap the crank/flywheel as well. When I brought this to his attention, he sold me a sidecase and all gears/axles/cover for his cost., ~ $198...I haven't had a problem since and I inspect every oil change.

Check out this link and see if the punch mark is already there. If so the recall has been done. All it was is the flywheel was not properly tightened there was nothing wrong with the woodruff key itself.

http://www.off-road.com/dirtbike/projects/wr450f/2003_04/runright.html

I have a problem with the last bit of advice on that page. Routing the breather hose to the airbox is a good idea, but placing it in the bottom is not. All the crap and moisture will collect at the bottom and the likelihood of it getting sucked up by the breather hose is very good if you follow the directions on this website. My recommendation is to route the hose to the top of the airbox, not the bottom.

Duuu, of course mount yhe hose in the top. The bottom of the airbox has a drain. :applause:

i would buy the 2004 parts as a bare min.

i would buy the 2004 parts as a bare min.

Simon is right! Remember as a kid we always did what Simon says!

My advice is to do what it takes for you to feel comfortable. If that means lapping and locktiting the flywheel and/or upgrading the starter parts, then do it.

I tore my 03 down after taking delivery and found the flywheel taper did not match the crankshaft taper. Not even close. Looked like a failure waiting to happen. So I lapped it to match, remounted it with locktite and have gone 7500 miles of hard off roading with absolutely no problem. Mine bike backfires occansionally, sometimes hard, sometimes while cranking the starter...no problems. Others, as you have read, have had differing experiences and applied different fixes. I can only speak for myself.

So my 2 cents worth (and 2 cents ain't worth much these days) is that if your bike has a lot of miles with no issues, its probably just fine. Stop worrying about it. But as always, YMMV.

How was that for totally useless advice? :applause:

VMXR,

Ran across your post on the flywheel key problem and read with interest the part about tapers not matching and lapping the tapers! I wasn't even aware of the problem as I'm a old vintage guy and work with only vintage machines. Thought I might throw out a few things to ponder gleaned from working on high performance Jet Skies in the 80's which I'll bet may still apply.

The flywheel taper is not the same as the flywheel for a reason.........! When the nut is tightened that holds the flywheel, it distorts the taper in the flywheel opening up the back side! What you want is when the nut reaches the called for torque, the flywheel has distorted to match the taper of the crankshaft to achieve full taper contact. Tapers should be clean and dry! Torque wrench must ALWAYS be moving when torque is reached! If over or under torqued you will not receive full taper contact! Wonder how many were rattled on by some clown with a air wrench?

Wonder what Yamaha did to fix the problem......changed the taper or just the difference between the two tapers or both??? Maybe changed the flywheel nut torque or the key also?? Anybody know...................I'd be interested in knowing???

Kind of made me wish I was back working in a dealership shop for a minute..............almost! Didn't take long to get that thought out of my head!

Old School Al

Wonder what Yamaha did to fix the problem......changed the taper or just the difference between the two tapers or both??? Maybe changed the flywheel nut torque or the key also?? Anybody know...................I'd be interested in knowing???

I checked with Yamaha and they blamed the problem on a kinked airline which didn't allow the flywheel nut to be tightened properly (about 18 LBS instead of 54 I think) allowing the flywheel to come lose and shear the key. When the recall was done at the dealer before selling all they did was check and tighten the nut as needed. If the bike came back in after it sheared it was disassembled and parts replaced including the crank if needed.

The flywheel taper is not the same as the flywheel for a reason.........! When the nut is tightened that holds the flywheel, it distorts the taper in the flywheel opening up the back side! What you want is when the nut reaches the called for torque, the flywheel has distorted to match the taper of the crankshaft to achieve full taper contact. Tapers should be clean and dry! Torque wrench must ALWAYS be moving when torque is reached! If over or under torqued you will not receive full taper contact!

Hey Old School, I am well aware of everything you mentioned. However, I did not bother to mention it as I tend to think of this stuff as common knowledge. Thanks for pointing it out!!

As for the tapers in question on my bike, after torquing to spec, roughly the most inboard 75% of the taper made no contact at all! I took the bike over to a machine shop that does a lot of similar work for the defense industry and had them supervise me (I ended up watching for the most part) while matching the tapers. Inspection revealed the taper on the flywheel to be very poorly machined. A bad batch from a subcontractor maybe?

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