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New (to me) KDX400 w/ questions.

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I've ridden a lot of bikes when I was younger but just acquired my first one. KDX 400. I know nothing about them. I can remove a front clip and pull a Chevy motor in an 1 and 1/2 but was never in the bike world. I've always liked bikes, just seemed something else always came up. It was made in 80. It's kind of a bad deal cause everything I was told about the bike does not match up with manufacturing years. I was told it was made in 82 which I believe would make it a 420 instead of a 400. Any insight would be great. I do know it has enough torque it could climb a tree if need be. 

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Don't like telling what I I've got invested but I've had it 3 days cleaned the carb and it runs like a top.

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My dad and uncle's farm know all the neighbors can ride all day and just cross roads. That's why I've always wanted a bike. Not sure if it's more work than what it's worth.

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Definitely a 400.  .392l cast into the cylinder.

I would get a proper air filter for it.  That one doesn't look like it fits quite right. 

Those are cool bikes.  Big bore two stroke, that's going to be fun.

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Yes there is some work involved. I've got some clutch work too. First thing is tires, dry rot. Then filter and plastic. I'm second owner of this beast.

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1979 KDX400-A1, the very first KDX model made.

 

Congratulations.

 

Dan, it is actually the stock filter. It's the old metal can deal.

 

Chad Harter, look up UNI filter or maybe Twin Air brand air filters.

 

Thanks for working on it.

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Next thing to do is pull the head and take a look at the plating in the bore.  Hope for the best but don't be surprised if it needs a replate.  Better to do it before it blows up.

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Thanks for the info anything else you know I would love it. That's some good need to know stuff. 

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What would be some good 2 cycle oil for it. I mixed stihl chain saw oil 25:1 just to get it running.

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I think you would be better off at 40:1 or so, when using motorcycle oil. Since it is a 400, I don't think you will be keeping it pinned open.

 

Unless you want to look around for an air-cooled oil, most any good 2-stroke motorcycle oil will be good.

 

There is no need to worry about power valve cleanliness.

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Cool bike ???? ya i dont think you need to run 25:1 . 40:1 with the stihl oil be better its good stuff

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Posted (edited)

So I had a 79 KDX 400. It was rated at 40 hp.  I had the bore sleeved like in the 80s. LOL!  Did you get this in Montana? LOL. It would drink so much fuel that you could literally see the fuel level drop while on the throttle.  When you were in the powerband there was no way to bog the engine down.  I did lots of hill climbs with the wife on the back at full throttle. I can still feel her punching me in the ribs too this day.   Ha

 

They only made it for two years and then went to the 420.

Edited by Utah Rider

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Thanks for the info guys. Replaced clutch cable today and took it for a ride. Had a blast. Hopefully next week new tires and bushings

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AAAHHH HHAAA  a great old time 2stroker FUN BIKE  ,, just a correction from a previous dude 

that cylinder does NOT have plating  = it is good old boreable metal and can be bored 6-8times for a loooong life 

those old 2strokes were built for LOTS of oil 20:1 and 24:1 were VERY common for them and they ran forever on that old fashioned 2stroker oil

 with todays supersynthetic stuff I would still keep it rich 32:1 because pistons $99 are alot more than sparkplugs $3

and none of that adjustable exhaust valve krap   JUST RIDE AND SMILE 

your gonna have YEARS of fun with that old timer twinshock airkooled drumbrake 2smoker  ,,

still have my old 76rm125A and take it out few times a year for time machine experience = I am 12yrs old on that  , next day back to oldman 50++

DDD

 

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Sure looks plated to me. 

https://www.ebay.com/itm/1979-Kawasaki-KDX400-Cylinder-1699/264256152641?epid=1123657180&hash=item3d86e4e441%3Ag%3Asq4AAOSwcBhWatIT&LH_ItemCondition=4&frcectupt=true

Kawasaki started using electrofusion in the mid 70's.

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10 hours ago, dan197man said:

AAAHHH HHAAA  a great old time 2stroker FUN BIKE  ,, just a correction from a previous dude 

that cylinder does NOT have plating  = it is good old boreable metal and can be bored 6-8times for a loooong life 

those old 2strokes were built for LOTS of oil 20:1 and 24:1 were VERY common for them and they ran forever on that old fashioned 2stroker oil

 with todays supersynthetic stuff I would still keep it rich 32:1 because pistons $99 are alot more than sparkplugs $3

and none of that adjustable exhaust valve krap   JUST RIDE AND SMILE 

your gonna have YEARS of fun with that old timer twinshock airkooled drumbrake 2smoker  ,,

still have my old 76rm125A and take it out few times a year for time machine experience = I am 12yrs old on that  , next day back to oldman 50++

DDD

 

I think all full sized KDX's had Electrofusion.

 

https://www.partzilla.com/catalog/kawasaki/motorcycle/1979/kdx400-kdx400-a1/crankshaft-piston

 

My user name is KDXgarage, not KDXWildGuess. :-)

 

If you see a KDX400 piston for $99, you better buy all you can find.

 

It's a 400. He's a car guy. I doubt he is going to be wringing the piss out of it. 40:1 will be better.

 

In the OLD manuals, they talk about OLD oil. If I was running OLD oil today, I would run more of it. Today's oils are better than when those manuals were written.

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Went to the local Kawasaki dealer. He was completely worthless. He was more worried about sales then to even consider helping me. Found out an old coworker of mine has a Shop up by Fremont, IA. The don't sell Kawasakis, I think they have KTMs and a couple others. He said bring it up and he will do everything he can to find parts to make it reliable and the way it should be. I like those kind of people.

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Kawasaki has long ago discontinued parts for those bikes.  There is next to nothing the guy at the dealer can do for you beyond a spark plug or carb jet.

You are pretty much on your own with the vintage bikes.  That's part of the fun.

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