new to the kdx world, whining noise!

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doctord23
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Post by doctord23 »

rsracer,

I am having a similar experience with an '88 that I picked up. A loud whirring noise that increases with rpm. I heard it when i bought it, but it was cheap enough that I thought I might just use it for parts for my '87.
My initial thought was crank bearings or flywheel (that year kdx's are known for the magnets coming loose).
I opened her up yesterday and other than some carbon build-up it the kips ports, everything inside looked clean and in good condition. As I started to get deeper into it, I pulled the clutch cover. Again, it is spotless inside and no metal shavings. As I started pulling the pieces out, the kips activator came out first. The shaft for it sits between two bearings, one on the crankcase and one on the side cover. For some reason, when I pulled it out, I stuck it in the side cover and spun it: Whirrrr is what I heard. I tried it in the inside bearing and it is quiet. The bearing on the cover looks fine, but I think I found my noise. Looks like I might not be splitting the cases after all.
I'm thinking that I'll put the top end together and try starting it without the kips gear installed to verify that the noise is gone. The moral of the story is to check every bearing. The kips shaft bearings are like $5 a piece. Keep in mind that the kips shaft, clutch basket and kickstart gears all spin all of the time although at different rpm's.

Has anyone replaced the little kips shaft bearings before? Is this where the freezer technique comes into play or do they just press right in.
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Post by rsracer »

probably not then eh?
1993 KDX 200. Bone Stock.
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scheckaet
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Post by scheckaet »

I just checked both of my bikes and that bearing sounds a lot like the culprit. I don't think replacing it will change the level of the noise at all.
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Post by rsracer »

>|<>QBB<
scheckaet wrote:I just checked both of my bikes and that bearing sounds a lot like the culprit. I don't think replacing it will change the level of the noise at all.
if it's the bearing on my bike it certainly will change the noise level.

My bike iddn't used to make this whining noise until recently so obviously something got messed up internally.

Also, when i kill the bike or turn the motor off it makes a bit of a screeching grinding noise before it dies. Is this still a bearing?
1993 KDX 200. Bone Stock.
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Colorado Mike
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Post by Colorado Mike »

Sounds like it. When you split the cases check all the tranny bearings. When my kid's YZ melted down, all the tranny bearings were bumpy too.
Mike

Life's tough, it's even tougher if you're stupid.
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doctord23
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Post by doctord23 »

I replaced the kips activator bearing and got it back together yesterday. I had to work a while to get the bearing out. I tried the grease technique, but ended up just working it out with a hooked screwdriver. The whirring noise has decreased, but it is still noisier on the lower end than my other bike. The noise doesn't change with clutch engagement. I think I'll go in deeper and replace the crank bearings at some point.
While I was in there I fixed the slipping kickstarter by stretching the ratchet spring.
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doctord23
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Post by doctord23 »

>|<>QBB<
rsracer wrote:>|<>QBB<

Also, when i kill the bike or turn the motor off it makes a bit of a screeching grinding noise before it dies. Is this still a bearing?
Sounds like a bearing could be frozen and the race spinning in the seat or on a shaft. I would pull it apart before I started it again. That does not sound good. Good luck.
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Post by rsracer »

Do you think this is something i can fix myself? I need a service manual and i really don't wanna pay an arm and a leg to have my bike serviced. Especially not if it costs as much as the bike is worth.

I'm very ready to get this thing back out on the trails it still runs fine however i just need to get this problem fixed.

If it's not to much, i would like to get into the bottom end myself and replace the bearings, let me know if you guys think i should get an estimate or just tear into it.
1993 KDX 200. Bone Stock.
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Julien D
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Post by Julien D »

Don't bother with an estimate, you'll get raped. It's not too difficult a job to split the cases, find the problem, and correct it. While you're there replacing main bearings and seals is good preventative maintenance (assuming that's not what's gone out), and make sure to check the condition of the lower conn rod bearing. Replace all misc bearings in the tranny, etc.

I did my bottom end rebuild for under $300, including a rod kit, crank rebuild labor, main bearings and seals, all transmission bearings, and a full gasket kit. You will have to have a flywheel puller and some sort of case splitter. Buy the tools, and if you don't think you'll ever use them again you can sell them when you're done.
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Post by Tedh98 »

>|<>QBB<
juliend wrote: I did my bottom end rebuild for under $300, including a rod kit, crank rebuild labor, main bearings and seals, all transmission bearings, and a full gasket kit. You will have to have a flywheel puller and some sort of case splitter. Buy the tools, and if you don't think you'll ever use them again you can sell them when you're done.
Did you buy OEM tranny bearings or did you get them from a bearing shop?
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Julien D
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Post by Julien D »

I got the main bearings and seals as a kit. All balls I think. Some people don't like them, but I've used the plenty with no trouble. For the misc bearings in the tranny I just visited my buddy who has a bike shop. He had everything else I needed.
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rsracer
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Post by rsracer »

I think i'm just gonna have to ride mine for awhile with that whining noise. It still runs strong and fine but it has a bit of a supercharger to it. haha.

do you guys really think this is such a terrible idea? One guy said he wouldn't even try to start it again. I've started it numerous times it fires right up and everything, there is just a slight whining noise haha.

Give me some input on whether or not you think i should ride it like this. I really want to hit the trails this weekend! And i don't have 500 bucks to have it serviced.
1993 KDX 200. Bone Stock.
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