Getting The YZ400D Ready

[Tahitian_Red]

I'm just about finished preparing my YZ400D for a grudge match against a friend and his RM370B.  I was going for the 1976 Trans-AMA Hurricane Hannah look.

[Iain Cameron]

I like your seat where did you get it , nice looking d

[mboddy]

Is it an IT400D seat?

[Tahitian_Red]

It's a replacement seat foam I got from X-treme Vintage YZ here in the U.S. (non-slip cover is from them too)  It looks a little wider than stock and is very firm.  I actually like foam that lets me sink down a little on longer travel bikes, so I may try foam from another vendor. ??

[mainline]

It's a replacement seat foam I got from X-treme Vintage YZ here in the U.S. (non-slip cover is from them too)  It looks a little wider than stock and is very firm.  I actually like foam that lets me sink down a little on longer travel bikes, so I may try foam from another vendor. ??

I reckon it looks the goods, a lot of the works bikes from that era seem to have taller seats (taller riders?) Anyway, cool bike, don't leave it sitting in your garden bed too long

[Tahitian_Red]

Getting ready for the second test race this weekend. 

The first time out was a pretty mild, wide open track with only two jumps (one being a table-top).  The track this weekend will be tighter with a few more jumps, but great traction everywhere, so we will see if my suspension settings hold up for this type of track.  The only changes I'll make will be more or less sag in the rear or sliding the fork tubes up or down, as I think the damping and spring rates are pretty close to correct.

I'm still interested to see if the swingarm flex rears it's ugly head. 

[vandy010]

and,
we'll need constant updates as to how that "grudge match" with your mate on the RM370 is going

[Tahitian_Red]

Vandy,

He sold the RM370 and went out and bought a 1992 CZ400, which is the same as a 1979 CZ400, to race and left me with a Pre-78 bike.   

As well as the Mighty "D" is running and as comfortable as I'm feeling on it, I'm willing to take on his 90's Czech Technology.  We will meet in June and I will have two or three prep races in before he and his CZ hit the track.
 

[Iain Cameron]

Tahitian -red , What settings did you end up useing for your suspension ? mine sill has stock settings .

[Tahitian_Red]

I have Emulators in the front forks (standard setting) along with new fork springs for my weight and lack of ability. 

The forks are from the "E" model and I'm running a 30mm spacer under the damper rod.  Don't think that would be OZ Pre-78 legal, but our rules have a loophole here.  You'll get the same performance from the '77 forks with emulators.

On the rear I have a Works Performance mono-shock w/ adjustable reservoir.  I lucked out and the setup they sent me works pretty good.  I only adjusted the sag to just under 3 inches (roughly 65-70mm).  I read a few negative reports about the Works mono-shocks, when they first came out a few years back, but mine works great (no Yamaha-Hop yet). An extra benefit is even with the reservoir they are nearly 3 lbs lighter than the stock shock.

Caveat:  I have only one race on these upgrades and I'll probably know how they will hold up after I beat that '92 CZ.