DT400 - the big-bang build: Big changes!

Re: DT400 - the big-bang build!

There's a knack to it, when you figure it out it's actually pretty easy. (even easier if you have someone to explain how it should be done)
The DT is a real easy starter, the 490 Maico wasn't too bad when warm, I could even start it without getting off (left side kickstart, left foot kick)
BTW, I also had a DT250 exactly like the one on front cover of manual, only difference was the tach cable was missing. Didn't mater though,tach still worked due to resonant vibration and was actually pretty acurate (I didn't even notice cable was missing for about 3 months ;D )
 
Re: DT400 - the big-bang build!

Great story about the tacho, pj.

The first of the web purchases arrived this morning:

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It's a slow process buying a bike one component at a time!

Crazy


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Re: DT400 - the big-bang build!

Some more NOS components:

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The parts from Oz are starting to trickle in; the purchases from the USofA shouldn't be too far behind.

Crazy
 
DT400 - the big-bang build!

There are lots of parts still available direct from Yamaha. A great resource is the Zedder parts interchange software.

The oil pumps are matched to the bikes, and the 77-78 version is completely different than the 75-76 version. The compression releases should interchange between the 74 - 360 and the 75-78 400's. The cable can be hard to find but they are out there.

Try Northwest Vintage Parts in Tualatin, OR. They are a good reliable source. E-bay tends to have a lot of pieces for these bikes too.

If you sign up at www.yamahaenduro.com, you will find a lot of help. I did a pretty detailed resto of a '78 under the same user name.

Watching the build with interest. These are neat bikes with good power.
 
Re: DT400 - the big-bang build!

Thanks for the information and the links.

Missed out on a new oil pump at auction but have a second-hand unit on the way, as is a compression release cable.
Hope to do a complete list of needed parts this week.

Crazy
 
Re: DT400 - the big-bang build!

I didn't have to get started DesmoBro - it was in pieces when I got it!

The frame is in pretty bad condition - I may scrap it. Replacing the monoshock is not something I have a solution for, and the two that came with the bike look beyond recovery.
Lately I've been thinking of trying to find a 70s RD chassis or perhaps an LC. The bike will probably be ridden on the dirt for only about 20% of the time so a road oriented chassis makes some sense.

Crazy
 
Re: DT400 - the big-bang build!

If only you were in the US, sir. I have an RD400 frame just sitting in my workshed.
 
Re: DT400 - the big-bang build!

Justin - thanks for the thought; international shipping makes a lot of possibilities unachievable!

Fortunately Oz was flooded with LC and RZ Yammies, so there is a good chance I can find a chassis for a reasonable price. The motors however could be a different story. We had a 250 production racing series that was very popular in the 80s, with the result that racing attrition and rev-head stroker fans did a lot of damage.

Don't ask me how I know!

Crazy
 
Re: DT400 - the big-bang build!

makotosun - I've been unable to access the Yamaha Enduro forum. It appears that their server is down.

Very frustrating as I was looking forward to being in contact with other DT400 owners!

Crazy
 
DT400 - the big-bang build!

stroker crazy said:
makotosun - I've been unable to access the Yamaha Enduro forum. It appears that their server is down.

Very frustrating as I was looking forward to being in contact with other DT400 owners!

Crazy
Click to expand...

Try again. The site is up. The owner has had some hacker problems, so sometimes hard to get registered.
 
DT400 - the big-bang build!

You know I'm watching mate!

I think a lot of the engine parts in the dt 400/250 were interchangeable with the YZ series of the same years.. I'd be finding out if that de-comp valve is in either the dt250 motor or the yz400 as they were a lot more common.

Good luck though, I know it will get there in the end cant wait to see it!
 
Re: DT400 - the big-bang build!

Thanks Ryan. I've got a decompression valve on the way so I should be okay.

The matter exercising my grey matter at the moment is the frame. I might have sourced an adjustable, re-buildable monoshock to suit the DT set-up. I will know in the next week if this is true; then I will go with the DT frame. If not, I will get hold of an LC/RZ frame and modify it to suit.

Crazy
 
Re: DT400 - the big-bang build!

If you can find a YZ250 pipe it will REALLY wake up the DT, probably 20BHP more than stock (I know mine was quicker accelerating and faster top speed than a 1983 Kawasaki 400 motocrosser)
 
Re: DT400 - the big-bang build!

Crazypj - thanks for the idea, I'll keep a lookout for one. My other idea is to get a custom pipe made.

Crazy
 
Re: DT400 - the big-bang build!

I don't remember who made the pipe on mine, it was Italian manufacture for 250.
I used two bags of exhaust packing in silencer, makes it act like a stinger when over packed.
I also modified reed block and remove restrictors from air box but was running stock carb and oil pump
It may have been a KX420 and not 400 Kawa, long time ago, I forget (it was on a beach though so not down to rider skill)
 
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