Strangest Clutch/Idler Sound...2006 YZ450F

I sidelined my RMZ450 and bought a 2006 YZ450F yesterday after it test rode incredibly well. I took it to the trails today for induction ride and it ran like a dream.

But my son took a tumble on his bike so I had to lay mine down and attend to him...it scared me to death watching my little guy do his first over-the-bars flight. Knocked the breath out of him only thank God!!

BUT, when I picked the bike back up to start it, it would not start for the life of me. A guy came by and showed me a routine to start it, but while we were kicking it, I noticed that after nearly each time the kick starter was kicked all the way down, I could hear a gear continue spinning for a couple of seconds right afterward. The guy said he did not recognize that sound but he rides 2Ts only. He suggested I ask around...so here I am.

I probably would not worry except it sounds like it is not lubricated when it spins. Kinda like a wagon wheel without lube makes that sound. So it is not the smooth effect I would expect.

I popped off the clutch cover and it was moist, but I was expecting to see more oil there?? I do not know much about this bike...first YZ for me.

Is this NORMAL and can I stop worrying? I stopped riding after that noise for fear it might lead to something worse. Also not sure but would have thought there was a lot of oil running through the clutch area. Might explain the dry gear sound??

Thanks Greyracer:

I read your links and searched further but couldn't find my exact situation in there so maybe I can explain it better:

1. When I was kick starting repeatedly and it did NOT start, we could hear this one gear keep spinning after each time you kicked it. So the motor was still off, and this gear was still turning and it sounded like metal on metal without any lubrication in there. I have owned a ton of bikes and have never heard this when you kick start it.

2. When I removed the clutch cover to inspect, the clutch itself has a very, very light film of oil on it...not very much at all. I tilted to the right side and nothing even dripped out. It does not seem normal and it could be the reason for that gear sounding so bad when it spins? Also, is that enough oil to keep the clutch happy?

I did not remove the entire right side of engine to inspect the kick starter gear itself, did not want to go that deep into it if that sound is no problemo.

In reading those TT links I agree that it is a loud bike anyway you look at it---mine makes all those same noises y'all mentioned. BUT since no one has mentioned my particular kick start gear noise, it just feels a little unique and troubling. Probably nothing but I don't want to find out the hard way.

Keith

Thanks Greyracer:

I read your links and searched further but couldn't find my exact situation in there so maybe I can explain it better:

1. When I was kick starting repeatedly and it did NOT start, we could hear this one gear keep spinning after each time you kicked it. So the motor was still off, and this gear was still turning and it sounded like metal on metal without any lubrication in there. I have owned a ton of bikes and have never heard this when you kick start it.

2. When I removed the clutch cover to inspect, the clutch itself has a very, very light film of oil on it...not very much at all. I tilted to the right side and nothing even dripped out. It does not seem normal and it could be the reason for that gear sounding so bad when it spins? Also, is that enough oil to keep the clutch happy?

1. If the engine doesn't start, nothing will be turning. The only possible noise it could make is from compression running past the rings or one of the valves.

2. Once again, it's a dry sump. That means that the sump, or crankcase volume, is supposed to be relatively dry under normal circumstances. The oil is pumped from the oil reservoir in front of the engine, through the engine and trans, including the clutch, then picked up and pumped back to the reservoir. You probably did not follow the links within the dry sump link I posted.

1. If the engine doesn't start, nothing will be turning. The only possible noise it could make is from compression running past the rings or one of the valves.

2. Once again, it's a dry sump. That means that the sump, or crankcase volume, is supposed to be relatively dry under normal circumstances. The oil is pumped from the oil reservoir in front of the engine, through the engine and trans, including the clutch, then picked up and pumped back to the reservoir. You probably did not follow the links within the dry sump link I posted.

I am officially on board with your dry sump info which makes sense for the dry clutch look---sad to admit I did review it firstly but needed a slap in the face to digest it:bonk:.

But there is definitely a gear or something that continues to spin after you try and kick start the bike...it is not the piston or valves. The sound originates between the kick starter and the clutch. It truly sounds like the kick start gear goes into a free spin after you kick it. Could it simply be that it disengages after it turns the crank and I am just hearing it spin after it does its job? It just sounds wobbly and un-lubricated is why it has me concerned.

All this noise is heard when the bike fails to start, it is when you are trying to kick it over and after unsuccessful kicks I hear this sound of a gear spinning. I don’t know anyone with a YZ450f around here so I cannot compare notes.

I have never heard this before on any bike I have owned and just want to make sure this is just one of those enigmatic Yamaha sounds and not indicative of something that could lay waste to the engine.

I had a neighbor listen as I kicked it through to confirm the sound and vice versa him kicking with me listening...same interpretation. The sound appears to originate between the kick starter and the clutch basket...so it is definitely on the lower part of the engine.

I see everyone solving a lot of unusual things on here so I figured someone might have a notion about this. Maybe this’ll just go down as my own unsolved mystery?

The thing is that none of the gears in the primary case (there are 9 of them) disconnects from the engine or freewheels in any way on any shaft in the way that you describe. The kick starter gear freewheels on the kick axle IF the engine starts, but not if it doesn't. It stays meshed with the idler gear, which stays meshed with the gear on the back of the primary gear, which is fixed to the primary driven gear assembly, which, of course, stays meshed with the gear on the crank. If the crank isn't turning, none of these others (or the oil pump or balancer gears) can turn, either. You aren't hearing what you think you are, but it would be interesting to know what it is.

Got home and this time I pulled the clutch cover off, held down the kill switch and started kicking.. And I got a whole different read on that noise.

It is the clutch plates moving within the clutch basket when you kick it through and with the cover on there seems to tweak the sound enough to sound like a gear spinning. But with the cover off it became very clear that nothing else is going on---just some rattly parts.

Everything appears torqued down as it should be, just the clutch plates have a small amount of play in the basket like they should have so they can move.

Thanks for lending your brain cells to this...I vow no more bizarre YZ issues!!

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