Installing a New Piston in a 1991 KDX200

[@TepcoCycleRepair]

The heat discoloration you saw on the crank is from putting the connecting rod pin in. They heat it up when installing.

[@GoRideChannel]

I had no idea...thanks for the info!!

[@iokarus]

music way louder than your voice, nearly blew my ears away. Thanks for the video.

[@GoRideChannel]

Sorry about that - I do the best that I can in post, but years in and I'm still getting the hang of it.

[@gabewilliams5993]

Great, informative, video! Excited to see more KDX videos!

[@GoRideChannel]

Thanks! I've just gotta put everything back together. I've been super short on time over the course of the last 3 or 4 months.

[@gabewilliams5993]

Go Ride Channel I’m going to be doing a similar rebuild on my 99’ 200 this year. It’s gonna be a nice project that I hope turns out good.

[@gosolobox]

glad you caught that chunk of metal in the piston..

[@GoRideChannel]

Haha, me, too! I love your panniers, btw. I beat the HELL out of mine and they're only slightly loose. (lots of crashes off-road) Also I can take a ton of crap with me whether camping or going to the grocery store.

[@gosolobox]

@@GoRideChannel That's awesome. I didn't realize you had a set of my panniers. I picked up a KDX 200 yesterday....

[@GoRideChannel]

KDX is a great bike for the money. In California you can get them reliably for $800-$1500 and they're still fairly well supported in terms of parts with vendors like Jeff Fredette Racing. The panniers are awesome! I have them on my second generation KLR 650 and put them on right before I took it out to Death Valley. I was a little underwhelmed initially when fitting the racks, but once I got to using them I love how durable they've been and how much space they provide.

[@AlluringFishing]

Try a pair of split ring pliers next time. That would be easier that a screwdriver and needle nose pliers....

[@SoddingaboutSi]

I have the SR model (lower power for road) How long would you expect rings to last?

[@GoRideChannel]

Hi Simon, I'm not really sure, I don't think that was a bike that came to the US - I try to change mine out every couple hundred hours or so, or when the bike starts getting down on compression. I'm not even 100% sure what the manual says as far as service interval. In general, it's tough to say because the life expectancy of the piston is going to depend on an number of things, not the least of which riding style, oil quality, oil ratio, etc. On the 220's, they had issues with the pistons actually breaking, but on the 200's, they're less prone to catastrophic failure so I'd change it out when the bike is down on power and compression.

[@darrellcherry9172]

FYI, there is something called a crow's foot to torque those cylinder bolts. It's basically a wrench that attaches to the torque wrench. I think the crow's foot needs to be at a 90 degree angle to the torque wrench to get an accurate torque.

[@GoRideChannel]

Correct! they have special torque wrenches where you can get into places like that, or you can use the ratio of the distances between the spring and the centerline of the bolt and the spring and the centerline of the ratchet anvil as a multiplier.

[@dudefromkeene]

So you didn’t have to hone or bore the sleeve? Did you have any machine work done? Was your bike not running?

[@GoRideChannel]

The KDX200 Cylinder has a Nikasil coating on the inside making it unnecessary/ill-advised to actually bore out the cylinder. If it is scored, that's another story, but if all you're doing is normal maintenance, just cleaning is usually all that's needed. Some guys will run a ball hone through it or scotch-brite it if it is glazed, but I didn't have that issue. The bike still ran - usually you don't want to let them go quite that far - it was just getting harder to start and down on power. Hope this helps!

[@dudefromkeene]

@@GoRideChannel Yes it does thank you, When we took off the reed cage I saw some scoring. Does that mean I need a new cylinder sleeve? I bet that is pricey what's a good place to get one?

[@GoRideChannel]

@@dudefromkeene It would be the right thing to do to replace or sleeve the cylinder, but if it isn't too bad and you're really trying to get the bike back together you could knock the ridges off with a hone and say a prayer. Relative to some of the modern 4-strokes, parts for the KDX are relatively cheap. You can get a sleeve from any of the major online companies; Bike Bandit, Rocky Mountain ATV/MC, MotoSport, etc. for about $125...

[@dudefromkeene]

@@GoRideChannel I think I'm going to have US chrome redo the cylinder. From what I've read it looks like those have come out good. Thanks again for the help! You got me pointed in the right direction. How often would you suggest rebuilding the top end before it starts to score the cylinder?

[@GoRideChannel]

You're supposed to check it about every 600 miles per the manual, so for most people, that's probably about every 20-40 hours. In all reality, the bike is pretty low maintenance, so replacing the piston and/or rings usually is only necessary once every 100-200 hours. It depends a lot on how you ride, where you ride, what oil you're using, etc. Difficulty starting and slightly reduced compression are some of the indicators I'd use to determine that it is time for a top-end rebuild.

[@Frisky_FZR]

I freaked myself out there the KDX200 service manual is incorrect it shows the piston port facing the exhaust direction almost shat myself 😅😅

[@apicolatremoladalamercedch1039]

Que piston se podria adaptar al kdx200?

[@TheTruthMatters]

Did u put a gasket between the cylinder and case?

[@GoRideChannel]

Yeah, there is a gasket that gets installed between the case and the cylinder. I apologize for not pointing it out - it can be seen in the video sitting on the case at approximately the 8:00 mark. Hope this helps! Good Luck!

[@1MACVSOG1]

Did you clean and film doing the power valve, and timing for it????

[@GoRideChannel]

I didn't, specifically - sorry!

[@shellylangrehr1034]

What size piston goes in it I have the same bike

[@jasonjavelin]

@@shellylangrehr1034 3yrs later so I’m sure you got an answer but 66mm is stock for an e series KDX 200. (I just bought mine for a 94)

[@jessiedelacruz628]

Hello can i ask about kdx 200? I need to buy engine parts of kdx 200.. can you help me where is available engine parts of my dirtbike.

[@GoRideChannel]

I'm not sure where you're located, Jessie, but I'm fond of Dennis Kirk and Rocky Mountain ATV/MC. Ebay also can be a really good resource if you need a discontinued part.

[@COLBSKI999]

Did that bottom end hold up?

[@GoRideChannel]

I've only got probably 5 hours on it, but so far, so good!

[@edugarage8018]

viva chile xD