Noisy Clutch on 1999 KX 250

[ps2112]

I just bought a '99 KX 250 and am getting back into dirt biking/racing after a 20 year break. One thing I noticed was the motor was awfully noisy while idling. Upon further inspection, I noticed that if the clutch was pulled in(either in gear or nuetral) alot of the noise went away. it sounds like a diesel truck idling. Is this something to be worried about.
Thanks for the help

 

[KXTodd]

Sounds like you have a broken plate in there.

 

[darringer]

My guess is the needle bearing and sleeve that the clutch basket rides on is worn out. My Cr did the same thing and after replacing these parts the bike is quiet now. It will not cause any harm, but as I know, the noise will drive you crazy until you repair it. It's a straight-forward, easy fix.

 

[bigred455]

Believe it or not it is normal for them to make a little noise,then quiet down when the clutch is disengaged.I would have a look at the clutch basket finger's and look for deep grooves.The more the clutch basket get's worn the noiser it get's.To be totally honest the noise is normal,but yours can be excessive,check the basket.

 

[Senior KX Rider]

I would suspect the basket too.

 

[ps2112]

Looks like I'll take the basket out tonight and see what's what. I'm trying to go completely through the thing and lube and inspect, so I guess this is one more thing to check off the list. Thanks for the replies!

 

[bscottr]

Originally posted by ps2112
I'm trying to go completely through the thing and lube and inspect, so I guess this is one more thing to check off the list.

I agree that it's most likely the basket.

A little off topic, one thing about the KX that you'll want to lube well are the linkage bearings. Afterwards just know that they require very frequent attention (lubrication). Also don't be surprised if you find that the tips of the rollers in the lower shock bearing have broken off. This is very common, but a cheap replacement item.

I will say that you have great tastes in bikes. :) Welcome back. :thumb:

 

[Steve47]

Check everything but don't be surprise if you don't find anything wrong!!

All the KX 250 are making a pretty loud knocking noise when the clutch is not engaged. I had a 2000, 2002 and now a 2003 and they're all doing this.

My 2003 is making the noise (pretty loud), pull the clutch and it's gone. I checked a new bike to see and it's doing the same thing.

 

[ps2112]

I got a killer deal on the bike and so far it looks like all the previous owner did was put money into after market goodies and not ride it. The shock linkages were my next task to be done. I was just concerned because the motor was so noisey!

 

[bclapham]

check the pipe and springs for rattles as well, the KX's do make a lot of noise, i rode an 01 the other week and though it was gonna blow up, but its normal apparently!

 

[bigred455]

Originally posted by ps2112
I got a killer deal on the bike and so far it looks like all the previous owner did was put money into after market goodies and not ride it. The shock linkages were my next task to be done. I was just concerned because the motor was so noisey!

....

Do yourself a favor and see if the 03 kx 250 bottom shock mount bearing can be pressed into your 99 rocker arm.The 99 will have a different part numberthan the 03 because of the update which was well needed.I am guessing that it will fit,because the collars are the same.I have no play what so ever on my 03,and the needle bearing cage is different.Let us know. 1 more thing,when replacing the 0 rings for the kx 250 pipe, don't pay the 6.00 at the dealer for 2.These are a way better fit a lot tighter when you plug the pipe into the cylinder,use a little grease. O- TITE WIDTH 1/8" ID 2" OD 2-1/4" you get 4 of these in a package for 1.75 and I guarantee you the joint will not leak at all. I get these at pep boys other stores may carry it though.

 

[DEANSFASTWAY]

You know what can make noise on that motor is when the clutch hub nut comes a bit loose (it doesnt use a folding washer) and also the primary crank gear can make noise when only held on the crank by a circlip .They knock and youd almost swear that theres a chipped gear in the trans or something .

 

[ps2112]

Well I just got through tearing the clutch apart. And ,as was stated by several of you fine folks, there was nothing wrong. The internals looked brand new. No scratches gouges nothing. Dean I was thinking the same thing you posted. The crank has a bit of end play and if that nut was a bit loose I could see how it could make some noise. Also the primary crank gear, as you stated is wobbly. I think I'll see about making a bushing or something to tighten the bore up. Thanks again to everyone. Now it's time for the linkages. I think I'm going to install zerk fittings on each link and the swingarm to grease the bearings.
Again thanks to everyone!

 

[Studboy]

ps2112, tell us how the zerk fittings go, and maybe post us some pics! My friend's RMX250 has zerk fittings on both the linkage and swingarm! I wish my bike had those, it would cut down on maintenance time considerably. I would probably only take them apart once or twice a year then just to clean out any crud that accumulated, but sleep nicely knowing that they are always well lubed. :)

 

[bscottr]

Good heads up on the ’03 shock bearing Keith, I’ll check into that. I’ve found that if you don’t replace the collars when you replace the bearing, the bearing won’t last very long. I hope the ’03 has a better solution to the problem.

This is becoming a good thread for upkeep on the late model KXs. We might as well keep it going.

I installed zerk fittings recently to my linkage. It certainly makes it easier to lube on a regular basis. Due to the design of the lower shock bearing race and the race seat area in the dog bone, it’s not well suited for a zerk fitting. I’ve never had a problem with the swingarm going dry, so I didn’t install fittings there either.

Looks like I need to clean up better next time. :scream:

 

[bscottr]

Careful placement of the fittings will minimize the chance of knocking off the fittings by logs or when coming up short on jumps. I tried to “hide” the fittings behind the leading edges of the dog bone and swingarm linkage mount. For the top fitting I angled it for easy access (see the pic above).

 

[ps2112]

Great pics! That's exactly what I plan to do. I'm thinking about building some titanium axles just to be cool :-) One other question that maybe should be in another thread, My delta v-force reeds do not have the adjustible stop block. Could this be an old design and could I install a stop block from a new set?

 

[bigred455]

Originally posted by bscottr
Careful placement of the fittings will minimize the chance of knocking off the fittings by logs or when coming up short on jumps. I tried to “hide” the fittings behind the leading edges of the dog bone and swingarm linkage mount. For the top fitting I angled it for easy access (see the pic above).

.....

Nice job scott,it sucks you cant put a fitting around the shock bearing that is really where we need it,but I wouldn't either.As you mentioned the swing arm bearings stay in great shape on my 00 too.The 03 shock mount bearing(the bottom of course) when I purchased my bike I serviced the linkage and swingarm.The needle bearing's look a little longer in the cage,they also feel very tight rather than the usual slop.It also has this yellow coating in between each bearing on the cage.I hope we can replace the previous models with the 03 bearing.

 

[bscottr]

Originally posted by bigred455
I hope we can replace the previous models with the 03 bearing.

Me too! The slop you speak of is the root of all evil in that shock bearing. :(

 

[carlbielke]

I bought a '99 KX 250 too, after 20 years of not riding.
Incredible coincidence, or great minds think alike!
It seems the '99 was well liked, and hey, if it was good enough for Carmichael, it's good enough for me. I dumped the progressive springs before even riding the bike, it's in the shop right now getting a new pìston, can't wait to get my hands on my new sweetheart!
Are there any quick fixes for the front brake? It's rumored to be a bit mushy from what I've heard.
Great thread, I wish we had a site like the KDXers do.

 

[Mephisto]

haha YES i agree :D

 

[Fark]

For shirts and goggles... I had a 91 ZX7. Now that bike had a noisy transmission. Especially when you rolled it into the garage. Pull the clutch in, it goes away. I've learned not to worry unless there is vibration or tapping...

 

[DEANSFASTWAY]

NOISEY?? GSXR trans too. KDX 200/220s too.The straight cut gears on most clutch baskets and primarys are usually the cause of noises . Quads like Banshees & Blaster sometimes have angle or cross cut gears . On lots of new streetbikes they have a primary drive gear with a spring loaded thinnner sandwich gear running along side with spring wedging the 2 gears tight against the clutch basket. While this cuts down on noise it does make a bit of drag or frictional loss due to the gears working against each other Most racers take off the spring loaded gear. These are on like Honda CBR 929S 954S and also vt 1100 Shadows and Magnas . The Vt 110s also had a problem with the Spring loaded primary gears Knocking and sounding like a rod or piston knock and Hondo replaced a fair bit of them under warranty .CBR 600s get noisey when the timing chain auto adjuster goes bad and the scary thing is that it usually stays running with a loose chain . Suzuki Katanas will stay running even when the timing chain is sawing through the cylinder block .

 

[Fark]

Hahah Katanas. I don't konw how people classify them as starter bikes. Way too heavy, and old technology.