KX Guru Racing

This segment will deal with the installation of the clutch and ignition
and complete the bottom end portion of the rebuild.

First up is the clutch. The clutch outer was already installed in the
last section so now it's time for the rest of the components.

Install the thrust washer as shown.
Install the clutch inner.
Place a lock washer over the mainshaft.
Thread the retaining nut onto the main shaft. Clamp a clutch retaining tool
on the inner and torque the retaining nut to 59 lb.ft.

Bend at least one of the ears of the lock washer against the retaining nut.
Soak the fiber plates in gear oil.
I like to use OE Honda fiber and metal plates when using an OE cast
Aluminum inner and pressure plate. Clutch disc with Kevlar are hard
on the soft cast aluminum parts and may cause premature wear.
Load the clutch pack starting and ending with a fiber plate.

Apply Moly grease to both ends of the clutch actuating rod and insert into
the mainshaft.
Dip the clutch hat in gear oil and install.
Install the pressure plate, clutch springs and bolt/washers. Tighten the bolts
in 2 or 3 steps and in a criss cross pattern to 7 lb.ft.
Smear some gear oil on the clutch cover O-ring and install the clutch cover.
Tighten the bolts to 5 lb.ft.

Install the kick start lever and tighten the bolt to 20 lb.ft.
Spin the engine around. Dip the notched shaft of the clutch actuating lever
in gear oil and install (Blue arrow). Mount the stator plate with the two index
marks alligned and tighten the two retaining bolts (Red arrows).
Install the woodruff key followed by the flywheel, flat washer and retaining
nut. Tighten the retaining nut to 40 lb.ft.
Install the ignition cover.

Put the countershaft sprocket on the countershaft with the recessed side
facing the engine.
Install the convex lock washer (dome side out) and bolt. Tighten the bolt
to 20 lb.ft.

(AlisoBob Only changes I can add is using some thread-locker on the Kicker and Countershaft sprocket bolts. )
Install the chain guard.
Install the oil drain plug along with a new sealing washer.
That's it for the bottom end. Next up will be the top end.

As always, questions or comments are welcome.

dogger

Good point. I normally safety wire the CS sprocket for added insurance
(just haven't gotten around to it yet) and use a little Blue Loctite on the
drain plug. If you look closely at the picture, you can see the CS bolt
is already drilled for wire. This picture is from one of my other engines.
You caught me. Actually, I am going to install a 2000 CR250 ignition
with a Vortex IC. I documented the CR500 ignition in my post because
I haven't modified the 250 ignition yet. I'm embarrased to say, but I'm
not sure what the correct air gap is for the 500.

redrocket190

Should the white wire from the ignition pickup go behind the tab on the stator plate? When I took my rotor off the black sheath had been rubbed through, but the wire had not (yet) been damaged...

dogger315

Yes, good catch. Looks like I got careless since I knew I would be
replacing it before initial start up.

I've been using Hinson clutch baskets for many years and have never
had a basket bolt back out. I meet Hinson half way and use Red
threadlocker, but I don't peen the bolts. I had documented the basket
conversion process showing start to finish. Like you, I also treat
the installation as permanent (the OE unit is riveted). I guess it
comes down to your comfort level on the bolt peening. Here are
some pictures of what I did.

This segment will deal with cylinder prep, piston selection and
installation.

The stock CR500 cylinder is unique in that it uses an unplated steel
sleeve.
This is what the cylinder looks like right out of the box. Note the sprayed on
plastic protective coating.

Since this engine is being built for MX racing, I decided to have it ported and
machined specifically for that purpose. The port work is designed to up the
power but smooth the "hit" making the bike faster but easier to ride.

Even though the cylinder is brand new, it was bored .001 over to ensure a
perfectly concentric bore. In addition to the port work, the base was
machined to lower the ports (alter the timing) and the intake inlet and
exhaust outlet were matched to the VForce and exhaust flange respectively.
Reworked inlet
Reworked exhaust ports

Matched and "smoothed" Exhaust port
Matched and "smoothed" intake.

The base of the cylinder head was also machined to raise compression and a projected
nose spark plug is used.
Comparrison of BR8EV (non-projected) on left to BP8EV (projected nose).

Piston selection is critical on a 500. The increased power and vibration take
a toll on the stock cast pistons. I like to use a forged Wiseco for this
application. This piston is very strong and comes with a nice slick coating
Wiseco calls Armorglide. The piston feature reliefs and lightening holes
to keep the weight down.
It's a good idea to thoroughly clean the freshly machined cylinder and head
to ensure that all debris has been removed. Next, wipe the bore down with
ATF and a clean cloth repeatedly until the cloth contains only clean ATF.
Now coat the bore with clean two stroke oil, it's ready to install.

Prep the threads of the cylinder studs with Blue Loctite on the bottom and
anti-seize near the top of the threads and install with the rounded end of
the stud facing up using a stud installer or a pair of flange nuts. Torque to
25 lb.ft.

Coat the "small end" bearing with clean two stroke oil and install
Install a new pin in the left side of the piston leaving the gap in the middle
clear. Place the piston over the rod and push the pin through. Install a
circlip into the groove on either side with the gap at the 12:00 or 6:00
position. Make sure the circlip is fully seated.
I'll finish the engine in the next segment.