1979 KDX400A1 Restoration Started! (finally)

[IT400C]

Hi Guys,

I've had a clean runner KDX400A1 sitting in my garage for a couple of years now (as well as an A2 parts bike), and I've finally got to the stage where I can give it the care and attention it deserves...   

Dad had one back in 1979, and always said it was the best bike he'd ever owned.  So I've got this one to do up for him to do the occasional ride on.

Being mainly a Yamaha man, I'm a little unsure of some of the finer details that I take for granted on my IT's etc.

Things like what engine paints etc did the 79 KDX's have? 

• Were the Kwacka engines a Semi-Gloss Black?
• What about the hubs?  Semi-Gloss?
• What about the exhaust?  Flat or Semi-Gloss?

Also, anyone out there have any nice '79/'80 KDX400/250 sidecovers or mudguards?

Anyne got a good KDX400A1/A2 kickstart? 
Or does a kickstart off another model fit and do the job?

Does anyone do replica seat foams?

Haha - I'm starting with a VERY low knowledge base here....   

Thanks,

Tony

[IT400C]

(Sorry for the over-sharpened photo)   

[IT400C]

[cyclegod]

Here's some stuff....

http://www.ebay.com.au/itm/KICK-START-LEVER-KAWASAKI-1980-KDX400-DX400-/360369970061?pt=Motorcycles_Parts_Accessories&hash=item53e7b95b8d

http://www.ebay.com.au/itm/1979-1980-Kawasaki-KDX-250-400-Plastic-Kit-AHRMA-VMX-/280706182333?pt=Motorcycles_Parts_Accessories&hash=item415b646cbd

http://www.ebay.com.au/itm/SEAT-PAN-KAWASAKI-1980-KDX400-DX400-/360369952425?pt=Motorcycles_Parts_Accessories&hash=item53e7b916a9

http://www.ebay.com.au/itm/FRONT-SPROCKET-COVER-GUARD-KAWASAKI-1980-KDX400-DX400-/380343124234?pt=Motorcycles_Parts_Accessories&hash=item588e37810a

http://www.ebay.com.au/itm/KAWASAKI-79-80-KDX400-250-KLX250-tailight-23024-4001-/150695767519?pt=Motorcycles_Parts_Accessories&hash=item23162aeddf

http://www.ebay.com.au/itm/KAWASAKI-KDX400-SPEEDOMETER-1979-KDX-400A1-NEW-/120655388324?pt=Motorcycles_Parts_Accessories&hash=item1c179f1ea4

http://www.ebay.com.au/itm/Kawasaki-KDX400-KDX-400-1112-Cylinder-Jug-/110701257545?pt=Motorcycles_Parts_Accessories&hash=item19c64f2349

http://www.ebay.com.au/itm/1979-KAWASAKI-KDX400-KDX-400-SPEEDOMETER-SPEEDO-250-450-/350448685469?pt=Motorcycles_Parts_Accessories&hash=item51985e919d

[GMC]

Good stuff.
I’ve been intrigued by this model for a while now. I’ve never been a big fan of big bores as they can be big cumbersome beasts at times, especially in the bush, but from looking into this model I have found that the tank, seat, swingarm & forks are all the same as the KDX 250 which has me thinking that the 400 may feel like a torquey 250 (or the 250 feels like a big cumbersome beast)


HTH

Part # = 36001-4001-7F
Part Description = SIDE COVER,LH,LIME GREEN
Model Count = 3
KDX250-A1 80 250 KDX250 OFF ROAD
KDX400-A1 79 390 KDX400 OFF ROAD
KDX400-A2 80 390 KDX400 OFF ROAD

Part # = 36001-4002-7F
Part Description = SIDE COVER,RH,LIME GREEN
Model Count = 3
KDX250-A1 80 250 KDX250 OFF ROAD
KDX400-A1 79 390 KDX400 OFF ROAD
KDX400-A2 80 390 KDX400 OFF ROAD

Part # = 35022-4001-7F
Part Description = REAR FENDER,LIME GREEN
Model Count = 2
KDX250-A1 80 250 KDX250 OFF ROAD
KDX400-A1 79 390 KDX400 OFF ROAD

Part # = 35004-4001-7F
Part Description = FRONT FENDER,LIME GREEN
Model Count = 2
KDX250-A1 80 250 KDX250 OFF ROAD
KDX400-A1 79 390 KDX400 OFF ROAD

Part # = 23005-5002-7F
Part Description = HEADLAMP BODY,COMPLETE,LIME GREEN
Model Count = 11
KDX175-A1 80 175 KDX175 OFF ROAD
KDX175-A2 81 175 KDX175 OFF ROAD
KDX175-A3 82 175 KDX175 OFF ROAD
KDX250-A1 80 250 KDX250 OFF ROAD
KDX250-B1 81 250 KDX250 OFF ROAD
KDX250-B2 82 250 KDX250 OFF ROAD
KLX250-A1 79 250 KLX250 OFF ROAD
KLX250-A2 80 250 KLX250 OFF ROAD
KDX400-A1 79 390 KDX400 OFF ROAD
KDX420-B1 81 420 KDX420 MOTOCROSS
KDX450-A1 82 420 KDX450 OFF ROAD

Part # = 13064-5003
Part Description = KICK PEDAL ASSEMBLY
Model Count = 9
KX250-A7 81 250 KX250 MOTOCROSS
KDX400-A1 79 390 KDX400 OFF ROAD
KDX400-A2 80 390 KDX400 OFF ROAD
KDX420-B1 81 420 KDX420 MOTOCROSS
KX420-A1 80 420 KX420 MOTOCROSS
KX420-A2 81 420 KX420 MOTOCROSS
KDX450-A1 82 420 KDX450 OFF ROAD
KX500-A1 83 500 KX500 MOTOCROSS
KX500-A2 84 500 KX500 MOTOCROSS

Part # = 53001-4002
Part Description = SEAT ASSEMBLY
Model Count = 3
KDX250-A1 80 250 KDX250 OFF ROAD
KDX400-A1 79 390 KDX400 OFF ROAD
KDX400-A2 80 390 KDX400 OFF ROAD

[IT400C]

Dad rode an IT400F in 1979, which he liked. 

But then in 1979 he got the KDX400A1 and instantly fell in love with it.  Guys that he struggled keeping up with on the IT, he was suddenly faster than on the KDX.  He described it as the most confidence inspiring bike he'd owned.


He described it as turning extremely well (steep forks), but it was very stable in the fast stuff as well (long wheelbase/swingarm).  It felt very light to ride and was very well balanced too.

The power was linear and it just seemed to get traction everywhere.  He used to say that no matter where you were or what revs you were doing, if you wanted to go faster, you just turned the throttle a little more..   

He loved it, which is why I'm restoring one for him.

And me too of course...   

[Davey Crocket]

You two are dribbling lunatics 

[IT400C]

You two are dribbling lunatics 

Hahaha - the voice of experience.....   

[GMC]

You two are dribbling lunatics 

It sure beats dribbling politics 

[firko]

You two are dribbling lunatics 

It sure beats dribbling politics

Hallelujah Geoff!
It look like a sensible conversation about motorcycles to me. Go for it Tony, they're a good thing, a friend in the USA rode desert on a KDX400 and he still reckons it's one of the most overrated bikes of the late 70's early 80's.

[IT400C]

Hallelujah Geoff!
It look like a sensible conversation about motorcycles to me. Go for it Tony, they're a good thing, a friend in the USA rode desert on a KDX400 and he still reckons it's one of the most overrated bikes of the late 70's early 80's.

Yo Firko, I hope you meant to say 'underrated'...   

[Canam370]

 
It look like a sensible conversation about motorcycles to me. Go for it Tony, they're a good thing, a friend in the USA rode desert on a KDX400 and he still reckons it's one of the most overrated bikes of the late 70's early 80's.
[/quote]

So you are saying they are a poxbox Firko?

[bigk]

I have a magazine test on one and it reads pretty good.
K

[firko]

Go for it Tony, they're a good thing, a friend in the USA rode desert on a KDX400 and he still reckons it's one of the most overrated bikes of the late 70's early 80's.   

Doh! Another Homer moment, brought to you by Acme brand Early Onset Dementia.
In a burst of rabid excitement at the thought of leaving the house in the pissing rain to do my weekly shopping at the mall, I wrote the post and hit send without my usual pre send edit. Underrated was of course what I mean't.   

I actually considered turning one of these KDX puppies into an Evo racer a few years ago. I'd acumulated most of the bits from various Kawasaki models but in the end I figured I had way too many bikes so it got shuffled onto eBay . Doesn't Simon Healy race a KDX based bike in Evo in Viper?

[JohnnyO]

Firko that Evo bike that Simon built is a KX250A5 with the KDX400 engine and it now belongs to Rusty. It's a good thing.. i had a ride on it a few weeks ago.

[bigk]

That's the 2nd one John, the REAL one is still with Simon undergoing preparation for next season.
K

[holeshot buddy]

thats right simon still has his original one
which is due for a birthday makeover
simon built mine i just finished off the easy bits
i would have to say its the best twin shock bike
i have ever ridden by far great motor unreal bottom end and midrange
and rides like its on rails

[JohnnyO]

i would have to say its the best twin shock bike
i have ever ridden by far great motor unreal bottom end and midrange
and rides like its on rails

Except for a Maico 

[holeshot buddy]

ha ha no its better than a 490 maico

[shorelinemc]

and if any one gets excited i have one for sale

[Trent Farlow]

This is for KDX fans.  There is some interesting history on the KDX400 and its great engine. The KDX400 has to be one of the most under rated bikes of the Evo period. All tests of the period were lavish in their praise of it. It was designed in the USA by Americans and was built in the new Kawasaki factory in Lincoln, Nebraska. The engine was shipped in complete from Japan, as was the swingarm and wheels etc but the tank and plastics were sourced in the USA - which probably explains why the KDX400 plastics did not wear well compared to other Kaw plastic of the same era. It had stump pulling power and could reach almost a  hundred miles an hour tapped out.

Brad Lackey joined Kawasaki in late 1978.  In his first months with Kawasaki, Brad initially practiced on a twinshock open class works bike which looked like a KX250A5 from a distance, however in common with most works bikes it was actually nothing like an A5, but was powered by a 390cc modified KDX400 engine. This was while waiting for his new works Unitrak to be built and flown in to the USA.

The KDX400 powered twinshock works bike was successful and a second one was used by Gaylon Mosier in the USA. If you look at Brads book - Motocross - techniques training and tactics - there are quite a few photos of him riding it. When the works Unitrak arrived Brad parked the twinshock 390 and it was purchased by Kawasaki UK and shipped to the UK for use by future 3 time world champ Dave Thorpe.  Dave Thorpe used it for several months in the UK and did very well. He only stopped riding it when his own works Unitrak arrived in April or May 1979. Both the Mosier 390 and the Lackey/Thorpe 390 still survive to this day. To make the engine more MX orientated Kawasaki changed the pipe, jetting, ported the cylinder and changed the gearing and once installed in a more MX orientated frame and suspension it did the business.

So the humble KDX400 has some history.

[JohnnyO]

Interesting stuff Trent...where did you find that info?

[firko]

Good stuff Trent, what a relief to have an interesting bit of motocross history instead of the doom and gloom over at Politics Central elsewhere on the forum.

[crankpin]

Makes me want to build one myself 

[JohnnyO]

Makes me want to build one myself 

After riding a similar bike recently i'd say that would be a good move mate..

[crankpin]

Got an engine for sale anyone? 

[firko]

It's probably a silly question but does the KDX400 engine bolt into the A5 frame or is it a bit more difficult than that?

[JohnnyO]

It's probably a silly question but does the KDX400 engine bolt into the A5 frame or is it a bit more difficult than that?

Goes straight in i believe Firko

[holeshot buddy]

hey firko i just put some current photos
of my bike on the ning site
go have a look

rusty

[cloggy]

 The swingarm was supposed to be built in the USa and was also used on the KLX

[TM bill]

Looks great Rusty , what pipe did you use ?

[IT400C]

It's probably a silly question but does the KDX400 engine bolt into the A5 frame or is it a bit more difficult than that?

The KDX400 was produced for 2 years (79 & 80) - I've been told that the A2 (1980) engine is easier to fit  -  the cases changed slightly between 79 and 80 at the rear engine mount area.

It's an A1 I'm restoring, but I do have an A2 parts bike in the shed... 

Sorry, wasn't planning on selling it though...   

[IT400C]

Has anyone tried the DC Plastics for the KDX?

From past experience they can be a bit hit and miss.  They look ok in the photos on their website, but....

[cyclegod]

The colour has a lot to do with how good/bad DC stuff is the green looks to be one of the better ones but if its not to your taste then try http://www.nightmare-racing.com/index.htm

[JohnnyO]

I have DC plastics on my 250A5.. they are rough, the moulds are not good and the sidecovers had to be heated and bent to get to fit properly. I'd much rather the Nightmare Racing plastics but these came with the bike.

[IT400C]

I'd rather the Nightmare stuff too, but near as I can tell, they don't make anything for the KDX400 - both guards and sidecovers are unique to the 79/80 model KDX400/250 only...

Btw, I believe the KDX petrol tank was made by Don Vesco - it even runs a Vesco petrol tap as standard...

[firko]

More questions.....
What's the advantage in using an A5 frame over the stocker? When I was considering my KDX project I only had an engine and intended on using a KLX 250 frame and Yamaha forks/twin leader drum and Fox shox. I figure the rarity of suitable A5 donor bikes would make it difficult so would a suitably upgraded stock KDX frame cut it?

[holeshot buddy]

hi bill its a modified kx420 pipe

firko the klx frame is ok to use very similar
i think there is more bracing on kx frame

trent would know


i would love gmc to make me a pipe but he is too far away :'(

[GMC]

i would love gmc to make me a pipe but he is too far away :'(

Not true.
The main problem as I see it is that your too far away

[Trent Farlow]

Firko - use the KX A5 frame - it has excellent geometery and adding the bigger engine just makes it feel even more planted. I do not know about using a KLX frame but would guess it would fit.  Rusty and Simon Healy have proved the concept with their success on them. The KDX frame is longer and does not have MX geometery, feels long on a track. Plus the KDX is a big bike when you sit on it, compared to the A5 which feels small. Although the fat thick KDX seat is a real pleasure. The engine almost drops into the A5 frame, you need revised engine mounting plates, and you have to machine down the steel collars in the rear engine mount where the swingarm bolt goes through , as the A5 has a smaller gap between the two swingarm inner pivots than the Unitrak which is larger.  The 1980 KDX400A2 uses KX420 cases - these are an easier fit than the 1979 KDX400A1 which uses a bracket to connect the motor to the swingarm.