KDXRIDER.NET

Hey guys, although I'm a longtime reader I just registered out of concern for a 1999 Kdx 200 I just bought. The bike runs good and feels smooth, however it sounds like it's about to come apart. The knocking is prevalent at lower rpm's but seems to be present at some degree throughout the rpm range. I understand that the kips valve on these bikes makes some noise but I didn't expect a diesel. Idk how well the sound will pick up on video but I'll give it a shot. So please help set my mind at ease and tell me what you think. Thanks guys!

Its difficult to tell from listening to the video....the kips do make a noise at low to mid rpm , some louder than most due to carbon build up etc.....you may have a little rumble from the main bearings?.....or even some piston slap going on....if you feel vibrations through the foot pegs when riding then this is a symptom of the main bearings on the way out, as for the piston then the only real way ( if you don't know its age ) would be a top end strip & inspection of the cylinder & piston....2 stroke dirt bikes , if had little use are prone to early bottom end & cylinder fails due to bearings going dry & condensation setting in causing rust ...not to mention oil seals drying out.

pull the clutch lever, see if it changes.

pull the stator (left side) cover and try to move the rotor up and down. if it moves, the crank bearings are going.

could just be a loose bolt or nut but I doubt it. kips usually sounds more metallic and light.

Thanks for the quick reply guys. I feel no vibration on the pegs and the bike feels smooth. I've ruled out clutch plates because activating the clutch had no effect on the sound. I'm almost certain the noise is coming from the top end. (that may just be wishful thinking) I've heard the kip's rattle described as a diesel on crack but this sounds like a diesel on crystal meth! I'm gonna pull the head of this week and check the cylinder. The top end was supposedly rebuilt about 10 hours ago but it could've been a hack job. Thanks again guys, I'll keep you updated. (unless its crank bearings at which case I'll go into a depression and won't be speaking to anybody)

Crank bearings are not that bad once you decide to just bite the bullet and do the job.

If I'm gonna have the case split anyways, is there anything else I should go ahead and replace just for preventative measures?

It would be sensible to rebuild the whole motor , top & bottom whilst it's apart...you may also want to think about getting it breathed upon too...you'll be surprised just how well a"tuned" kdx motor hauls!

Along with the main bearings, I would do the seals too at the very least.

You might want to also check the up and down clearance of the rod big end bearing.

There are several other bearings in the clutch side of the trans which should be replaced while you have it apart anyway.

So I'm feeling a bit better. I pulled the stator cover and checked the flywheel. Now I know this isn't foolproof way of checking bearings but the flywheel was absolutely solid. No up/down or in/out movement whatsoever. I'm going to at least pull the head off this week to check the top end. May need a new piston and cylinder replated. But if the top end is tight would I be justified in concluding that this noise is nothing more than a noisy KIPS? Thanks ahead for your replies.

Pull the jug, leave the head in place....Just saying....If the piston checks out, you can then remove the head and take a real good look at the Kips.
If it is THAT noisy, I'd suspect something is broken. Might be as simple as a KIPS gear, might be the whole top end.....Just be prepared!

Main bearings unless completely shot wont give much, if any real noticeable movement by grabbing the flywheel & checking for play as some bearings may have worn more than others.....when you remove the top end , grab a hold of the con rod & rotate the crank...if the bearings are on the way out you will certainly hear a rough noise.
My crank bearings had been noisy for months & months before I finally got around to changing them....I only had a very slight movement on the flywheel side.

Took the small round cap off the kip's main rod to see if it was hung up. It turned over fine at higher rpms. However, when I took the cap off spooge literally poured out. At least a tablespoon full of spooge ran to the ground. Is this indicative of anything other than rich jetting? After listening to it again today I'm convinced it's something in the top end. It sounds like its coming from the top end and the motor feels extraordinarily smooth when running. I would think it was kips rattle but the noise doesn't go away when the valve opens. Thus I'm willing to bet that when I remove the jug I'm gonna find a piston and cylinder that are beat to hell. At this point that would be good news. I'm still gonna check the rod for any up and down movement obviously.

I'm just here f for the carnage now. If it sounds that bad expect to be surprised it still runs. ;-)

The video I posted doesn't accurately represent the sound. I'll try to post anther when I get home.

Pulled the head and jug. Con rod has no up and down movement and minimal side to side movement. Piston and cylinder both looked new with the exception of some carbon build up on the piston crown from being jetted too rich. The bike is still rattling but it's running strong and cold starting first kick. Idk guys, I guess it's the kip's. It's my first Kdx and I want expecting the noise to be so pronounced.

Did you clean the KIPS put while you had it apart?
BTW I remember my bike being loud as well....Pretty sure I changed the type of gear oil I was using and it quieted it down......What oil are you running in the transmission?

I did clean the kip's and it made no difference, may have even gotten louder which is no surprise. I run 10w 30 in the great box. What do you guys suggest? Should I run a whole quart.

Try running type F ATF. I went from 10/30 to "Gear Saver" to Type F on my H series. When I went to the ATF is when the Kips got quieter. Not all KDXs like the same oils, so it can be hit and miss....
Use WalMart brand ATF (cheap!) and change it often at first...this helps clean out the 10/30.

Thanks man I'll try ATF, do you run a full quart?