At Pismo this weekend, my friend's 2002 Raptor made a horrible grinding noise while out in the dunes. He was WOT in 4 gear when the noise started. In neutral or in gear with the clutch in the engine would rev fine with no noise. When in gear and you let the clutch out the bike would move and would be a grinding noise, I witnessed this in 1st gear.

I tore it down today, no metal in the oil. Clutch looks fine. Some heat discoloration on the metal plates. Check out the pic, the discoloration is only on a portion on the plate. Each metal plate had the same discoloration in the same place. Do you think spring tension is uneven?

I don't think the clutch is the source of the grinding noise. I also think I can rule out any engine issues such as cams, valves, piston, etc since it would run fine in neutral. The starter works fine so that would rule out the infamous one-way bearing. It a 2002 so I thought it wouldn't have to trany problems, but it sure does sound like a trany issue. With out splitting the case, is there any other way to diagnosis the problem?

Clutch picture

 

That clutch plate looks pretty bad, check the clutch basket real good for cracks. But Im with you, im not sure thats the problem. You havent overlooked the front sprocket have ya?

I have seen em wear out very quick on the raptor, as soon as they start to hook they will chuck the teeth and skip on the chain which sounds ALOT like a grind.

 

Since you say it only makes the noise when moving, check the rear axle bearings.

 

I second the axle bearings. Mine went out in the dunes and I heard a grinding noise. I thought it was the chain slapping against something so I stopped. I only realized it was the bearings when I got back to the parking lot and jacked up the rear end. I pulled on the chain and the axle moved forward. I grabbed the wheel and I could wiggle the axle forward and back about 1/4" inside the carrier.

By the way, have you jacked the quad up off the ground, put it in 1st and let it idle. Then listen to see where the noise comes from. Engine or rear end?

I hope it is something cheap and simple. Good luck!

RR1

 

warrior007 nailed it! Front sprocket is toast. I was all ready to split the case, if it wasn't for warrior007, I would of skipped the obvious.

I must say the raptor is one of the worst bikes to work on, its seems in order to get to simple things you have to remove half the bike first!

Thanks for all the help!

 

That sounds like a nice fix. I will have to remember this one.

 

Just fixed my buddies, you should have seen those dogs on that front sprocket, all of them wrere sheered down, poor maintnence in my words but it's his bike..

 

Poor maintenance is right! There is no reason why the sprocket should even gotten close to the condition it is in, I'll post a pic of it when I can find my 32mm socket.

 

lol

One of my riding buddies actually thought the Factory put the worn wave shape on the sprocket and that you needed to make sure you got it back on with the wave going the correct way.

Didn't want to make him feel. . . well . . . stupid. . . but, had to correct him or others would think the same thing.

Yep, the sprockets do wear out. I had a 15 tooth for the DS that was missing a tooth. Funny thing, I didn't know it was missing until I opened my sprocket box to change the rear and out of the corner of my eye saw something weird. Musta broke while on the bike but, I can't believe I didn't notice it when I changed the sprocket.

Oh, and yes, you are right about working on the Raptor, I have to work on my Wife's this weekend and I have been putting it off for a while now. Gotta remove everything!

 

same thing happened to me, vibrating and couldnt finger the problem out. i bought a new clutch, changed the oil...no metal. and could not figure it out, then i took it to a buddy that has a warrior and he looked at it for about 2 hours, checked everything, sprockets, bearings and everything. finally he tyhrew a chain roller on the top part of chain travel, where it mounts to the frame and it cleared up. i couldnt believe i spent so much time and money on such an easy fix, but dang i was glad it wasnt anything major.