New owner of nice 04 KDX200

[TexasTom]

Howdy y'all :)

Back in 1992 when I was in high school, owning a KDX would instantly classify you as a super-cool-alpha-kid. The most expensive thing I owned back then was a golden Coca-Cola yoyo, so I was definitely low in the food chain...

Fast forward to last week, I was browsing the FB Marketplace and boom, that lady was selling her son's bike, and the next day I made my old dream come true. I didn't instantly become a super-cool-alpha-kid but I'm super happy and that's enough for me :-)

The bike has sat in a garage for the past 5 years (the kid preferred mountain biking) and before that, belonged to a military guy who was deployed a lot. So very low hours.

Pros: everything is nice and tight, no leaks, starts right away, good compression, and she's beautiful, the frame paint isn't even scratched...
Cons: smokey and doesn't really open up when revving.

Been posting that in the KDXrules! Facebook Group and already got a ton of advice on what to do with it: "fresh gas, new plugs, new tranny oil, carb cleaning, air filter cleaning, looking for gunk around petcock, replace fuel lines, flush front and rear brake fluid, new coolant, remove or cut out the top of the airbox lid, repack silencer, check swing-arm bolt isn’t rusted, clean out KIPS valve" and so on.

It's the first bike I own but I'm a DIYer with "some" mechanic notions, so I started to research and quickly found out that kdxrider.net is the absolute reference. So here I am, ready to learn from the experts!

Anyway, happy to be part of the family and sorry in advance for all the questions ;-)

[KDXGarage]

Around here, that's a lot better than a yo-yo! Nice ride!

Don't rush to cut out the airbox lid.

no packing to replace on the stock spark arrestor (the heavier, but quieter stock model)

Welcome to kdxrider.net.

check wheel bearings
clean and grease linkage and swingarm and steering bearings

First one last... buy a service manual... either a new / used OEM version or the Cyclepedia version.

[TexasTom]

Thanks KDXGarage, I got the manual with the bike ;-)

ok for for the airbox, repacking and bearings check.

Also I just bookmarked this post : viewtopic.php?f=77&t=12457, that's gonna help!

[bufftester]

Welcome to the forums and congrats on the new bike. All the above and get a torque wrench.

[TwistedRoot]

Congrats! Nice looking KDX! Read the jetting guide and you will save yourself a lot of time getting her tuned up.

[doakley]

Nice looking bike! Welcome to the cult!

[VTMTcowboy]

Welcome to the tribe man! I got a good laugh out of your opening paragraph as well lol.

[GATOROC]

Great find and beautiful KDX! You will find so much great information on this site. Enjoy, and welcome to the KDX family!

[TexasTom]

Few updates on that project...

While in vacation I ordered more stuff than I thought I would, and several hundred bucks later that's what I ended up with :

- An FMF Woods pipe + Turbine Core 2 silencer ;)
- Boyesen Power reeds + cage gasket
- new air filter + filter oil
- a dozen of BR8ES plugs with a Bosch HB063 5/8 In. Bi-Metal Hole Saw
- a carb rebuild kit (+jet gasket)
- a dozen jets from JetRus (MJ 142 to 155 / PJ 40-42-45)
- few feet of Tygon fuel lines
- a new petcock
- front and rear OEM exhaust damper mounts - $50 for both, delivered, that really hurt my butt...
- a TEKTON 1/4 Torque Wrench
- a 5gal can for my Ethanol-free gas
- 1/2 gal of engine Ice with new coolant hoses
- 1 bike stand
- 1 hitch mount bike carrier (Black Widow)

I don't want to spark the oil debate but I made my choice after 1 week of reading through the entire Internet, and this choice is only driven by what I think my riding style and conditions will be. And also the local availability. Anyway : AMSOIL Interceptor ($12.40/qt) for the engine and 10W40 Mobil1 4T full synt ($8) for the clutch. AMSOIL is not exactly easy to source but I have found a local distributor so I'll buy 6 Qts at a time.

Back from vacation, I started the teardown.

No really bad surprises so far. Only small issues like :

- broken exhaust damper mounts - will replace
- cut throttle slide boot - fixed with 3M Premium electrical tape...
- gunk and debris in the tank - now super clean
- petcock mostly obstructed - will replace
- air filter destroyed and airbox absolutely filthy - but it cleaned up nice

Tranny oil replaced. Coolant flushed and replaced. New plug. Completely removed the tank, soaked it in a large bucket with dish soap, used a stick with a microfiber towel zip-tied to one extremity and after 10mn of brushing I ended up with a perfect result. Inside in like new. I will replace the petcok.

Some pics and then a question for you guys !!

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[TexasTom]

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[TexasTom]

So my question is : since I'm here already, should I remove the top end to inspect the cylinder and piston for abnormal wear, or should I simply reassemble everything then just go for a ride to see if it runs normally ?

[bufftester]

You have the pipe off so you can get a look at the piston skirts on exhaust and intake sides and see if there is any major scoring or not. If you have a borescope you could drop it down the spark plug hole and take a look. IIWM I'd take it off so I could take a good look and also check the crank play and replace the wrist bearing (it's a 16 year old bike after all)

[KDXGarage]

Looking good so far. Nasty petcock!

Take it apart and check it out. Risk vs. reward.

[TexasTom]

Ok thanks for the advices guys

I guess I need to buy a new head gasket right? And since I’m here maybe a power valve cover gasket too? Just want to minimize the dismantling but definitely want to make sure there is no excessive gunk.

How about that kit? https://www.rockymountainatvmc.com/part ... 3028&v=598

Seems cheaper than a single NOs head gasket so...

[doakley]

Tusk will be fine.

[KDXGarage]

Cometic

[TexasTom]

Well, that sucks

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[doakley]

I don't like that. You've spent a lot to service and upgrade this bike. I'd send the cylinder to Millenium for service and replate. In for a penny, in for a pound!
(I also agree with KDXR, Cometic gaskets would be preferred, but ok to use Tusk if you already have them IMO.)

[TexasTom]

@doakley you did read my mind! I had a discussion with Millenium today, they have to check the cylinder to see if it just needs a replate or a repair. They couldn’t tell with just the pictures. I also asked for a Wiseco piston, cometic gasket and bearing because you’re right, I’m not gonna take a shortcut here :-) I’m removing the power valve and the studs tomorrow then I’ll pack and send it to Millienium (I considered Powerseal too but Millenium replied faster and have a quicker turnaround apparently)

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[KDXGarage]

You made the right call. Sadly, it's: