WR450 Kick Start Idle Gear Explodes... Why?

[Too Slow]

Hey Everyone,

Was adjusting my mixture screw on my 2003 WR450 and the battery was low so I was kicking it a bunch. Started it up and went to load it in the truck and heard a bang from inside the motor. Stopped and found that the kick start was no longer engaging.?

Pulled it apart and found that the kick start idle gear blew into pieces, chipped a tooth on the primary clutch basket and broke two bolts where the stopper goes. ?

Anyone have any ideas as to how this happened?

PS if anyone has a stock clutch basket for sale, I have an ad in the wanted section.

[schattat]

It looks as though the kickstart stopper (small piece of steel fixed into place by 2 screws) may have failed and snapped off and somehow got jammed into the gear thus destryoing it...

[MANIAC998]

First picture, lowest piece on the left. What the hell is that? I can't figure out where that came from. Also, you probably weren't done cleaning up the engine yet, but in that last picture, there's more gear material hiding in there. Maniac

[dgcars]

First picture, lowest piece on the left. What the hell is that? I can't figure out where that came from. Also, you probably weren't done cleaning up the engine yet, but in that last picture, there's more gear material hiding in there. Maniac

Looks like the remains of the stopper & 2 securing screws???

[bg10459]

It looks as though the kickstart stopper (small piece of steel fixed into place by 2 screws) may have failed and snapped off and somehow got jammed into the gear thus destryoing it...

+1.

A hard kickback can break the stopper... and the ratchet... and the gears...?

[schattat]

+1.

A hard kickback can break the stopper... and the ratchet... and the gears...?

Ask me how I know

I was able to get my WR for cheap $$$ after the previous owner had this problem:

Whilst trying to kickstart the thing decided to kick back and therefore the stopper snapped and caused the kickstarter-shaft to jump out if its seat and rip a chuck out of the casing

I was still able to fix it, though ? Has held up over 6000kms now

It looks a bit cleaner now after I removed the metal putty that was over the welded part...

[BajaFool]

Did the bike have the Starter Idler Gear upgrade to the 2004 model year configuration?

[danfromnb]

I'd say your kick start stopper broke first, taking the rest with it. Mine did last summer but I was REALLY lucky and the piece that broke off the stopper stayed between the gear and case making a light ratcheting noise (almost like the kickstart was being held down). I stalled on a hill and kicked it hard at a weird angle and it kicked back. The worst part of my whole experience was that the stopper was backordered and I had to wait a couple weeks.

Here's what mine looked like:

BTW: BIG thumbs up for your cardboard mock up to keep your fasteners straight. I was showing an apprentice at work how and why to do that today.

[danfromnb]

I just thought of something else to add:

Once I did get my bike back together I did a couple laps around the yard and rechecked for leaks, fluid levels etc. Everything was great so I tossed on my gear to go for a short ride. Halfway down my driveway smoke started to billow out of the bike and I could smell oil. Hit the kill switch and looked around, saw oil dripping from the rad... ***!? Turns out there is a crappy plastic plug held in by a set bolt where the decompressor lever came out of the head on older models and this plug blew out. I searched for the problem here on TT and found the commonly accepted way (best IMO) to fix this was an 18mm steel freeze plug. I just tapped it in with a deep socket that fit it well and after rechecking it a couple times, forgot it ever happened. I can't remember for sure but I think it was an 03-04 problem only, later years had a recast head with no hole.

I have no way of knowing for sure but I suspect the same backfire that killed the stopper generated enough of a pressure in the crankcase (and oil galleries etc) to loosen this plug enough for it to fall out. If it was me I'd replace it now. Go to a local engine shop and ask if they have one, they'll probably have to dig as it's a fairly uncommon size.

[Slick_Nick]

That's crazy!

[schattat]

Mate, you were lucky to get away with that! My bike needed a tonne more work done, see here ?

Wooded support:

The hole where the kickstarter shaft sits was no longer round and stright, so I rewelded the spot with a alloy bushing I made to fit the shaft and milled it down to make it flat and clean:

Not the cleanest solution, but why bother when you can't see it anyways, right??

[miweber929]

Looks good and solid. Better than buying a couple cases for sure!!