Honda CR250 Engine Build Part 5

[dogger315]

This segment will cover the installation of the clutch pack, right side cover,
power valve governor and water pump cover.

Before installing the power valve governor, coat the throwout balls and
the rack with a 50/50 mixture of moly 60 grease and transmission oil.
Place the 12mm plain washers on each end of the governor. Allign the
rack yoke with the bearing race on the governor and install as a unit in
the right side center case.


Apply the same lubricant mixture from the previous step to the pinion
shaft and bushing and insert into the right center case from the top
until it meshes with the rack.

This picture shows the correct orientation of the pinion shaft before
cylinder installation with down being the front of the case.

To install the clutch outer (clutch basket), soak the bushing and double row
needle bearing in transmission oil and install on the mainshaft end that
protrudes from the right side center case.


Place the clutch outer on the mainshaft and turn it until it meshes with the
idle wheel gear and the primary gear.


Coat the two dowel pins in transmission oil and install in the respective holes
in the right center case. Hang a new gasket onto the dowels and install
the right side cover onto the right center case.


I like to pre-soak the fiber clutch disc in transmission oil for 24 hours before
installation. Find a suitable container that can be sealed against airborne
contaminents, fill with transmission oil, place the fiber disc in the container
and close the lid. Pre-soaking assures the disc are thoroughly saturated
with oil and aids in clutch life and consistent clutch action.

This is an old salad container I swiped from the kitchen.

Next up is the clutch center. Install the large thrust washer then the clutch
center followed by the small thrust washer, locking washer and nut. Clamp
a clutch holder tool onto the clutch center and torque the nut to 60 lb.ft.
DO NOT TRY TO WEDGE A SCREWDRIVER OR SIMILAR DEVICE BETWEEN THE
INNER AND OUTER FOR THIS. You have a better than even chance of ruining
one or both of the components if you do. Once the nut is torqued, use a
pair of adjustable pliers to bend two of the locking tabs against the nut.


Load the clutch pack by alternating fiber and metal (or aluminum) disc,
starting and ending with fiber. Here is an oportunity to "tune" your power
delivery. If you ride on hard pack or otherwise have trouble getting the
power to the ground without excessive wheelspin, install metal clutch
plates instead of aluminum. The metal plates add rotational mass and
will tame the "hit" a little. Also, bare aluminum plates shill and foul the
transmission oil with aluminum particles in short order necessitating
frequent oil changes. Some may have already noticed the brown metal
plates in the previous picture. These are akadised aluminum which is a
hard coating designed to give you the benefit of aluminum plates without
the shilling.


Apply Moly 60 grease to both ends of the clutch actuating rod and insert it
into the hole (line) in the mainshaft.


Install the clutch "hat"


Install the pressure plate and six clutch springs


Install the six bolt/washers and tighten in three steps in a crisscross
pattern to 7 lb.ft.




Next up is the water pump. Coat the two dowel pins with oil and install. Place a new gasket on the dowel pins.


Place the separator plate over the first gasket.


Place a second gasket over the separator plate.


Now install the water pump cover and insert and tighten the bolts to 9
lb.ft. Install a new copper washer and the check bolt (black) and torque
to 7 lb.ft.


Install and tighten the remaining right side cover bolts to 7 lb.ft. By the
way, if you are using titanium bolts (like I am here), coat the bolts with
a ti-prep grease to prevent disimilar metal galling.


dogger

[Tonk]

this is a great series of threads your are doing dogger it will help alot of people in time to come, maby woody could make it a sticky at the top? but only 1 link then choose which thread to go to from that thread.

what year is this engine your doing i cant remember and do you have final cost of what its cost to buy all the component parts and extras such as oil grease etc to build this great looking engine.

Ian

[MXtras]

Excellent stuff! Great write-ups and fantastic pictures!

Scott

[Woody_393]

Wow, that is a great write up. That will help a lot of people for sure.

I would actually like to eventually move this to the knowledgebase.

[mrcribbs]

Awesome posts dogger... even better pics! keep 'em coming!

[brucem]

really looks good - thanks dogger

[dogger315]

Thanks guys. If you have any suggestions or would like to see
anything done differently, please let me know. Same goes for
questions on anything done so far.

Ian, I will summarize the cost of parts, tools, and chemicals when
I wrap up the build - so stay tuned.

dogger

[Tonk]

what other threads you plan on showin us don?

[dogger315]

This engine build is for a frame up restoration (more of a scratch build),
of a 1993 CR250. I am buying the frame and swingarm from Honda. I
will pick up some donor bikes for a stash of restorable non critical parts,
everything else will be new. I already have the front and rear suspension,
wheelsets, new OEM plastic, fuel tank, seat, airbox, computer and coil.

I will chronicle the entire build here like I've been doing the engine.
Hopefully, it will provide some useful information to folks.

dogger

[nutty]

What type of finish is on your case? Is that powdercoat, is it polished or something else? It looks great!

[dogger315]

Thanks for noticing, nutty. The finish is a color match (to the OE color)
powder coat. The paint on the clutch cover wears off on the first ride
on these bikes (most bikes for that matter), so I decided I wanted a
more durable finish. I used the trial and error method to color match
and it took me about 36 different attempts before I found a winner.
I powder coated the clutch cover, water pump cover, right side case
cover, ignition cover and cylinder head. The ignition cover and the clutch
cover are both trick magnesium pieces (the clutch cover weighs just 3 oz.).

I picked up a handful of used clutch and water pump covers on Ebay for
next to nothing. I NDIed them, media blasted the ones that passed then
powder coated. Now I have lots of spares that look brand new only
better because the finish won't wear off.

The rest of the engine is standard natural unfinished aluminum, just
the way it came from the factory.

Here are a couple of pictures of the color match.

dogger


The clutch cover on the left is a brand new OE, the one on the right is
powder coated.


clutch cover on left is standard aluminum with paint stripped, clutch cover
on right is magnesium. The powder coated magnesium cover is the one you
see in the engine build pictures.

[Woody_393]

I actually wondered the same thing. They look so... brilliant and clean.. I just thought it was your attention to detail and madness for clean

The cases really do look fantastic.

[ccnut]

The level of your expertise is amazing,You truely do have the gift. Can't wait to follow the rest of the build!!! Thankyou for sharing your knowledge with us..........Jerry

[dogger315]

Thanks guys, I like the way they turned out myself. The best part is, I beat
some of the spare covers with a mallet and it didn't even faze the finish.

The remainder of this build will probably take close to a year due to time
constraints caused by other projects. I can't wait to finish though; I plan to
rip up some tracks with it.

dogger

[OLDMXRACER 393]

I am speachless. We love this stuff here so keep em coming.
As comic relief to dogger's masterpieces, should I detail the Ace 100 I'm doing up for my lady?

[dogger315]

Thanks Andy, I for one would love to see that Ace 100 build.

dogger

[nutty]

I have my 02 cr250 at about the same point as far as the cases and cylider disassembled. After seeing how sweet and clean yours look Im thinking about getting mine powder coated also. But Im curious, how did you prep your cylider for powdercoating, to avoid any damage from media blasting and overspray, to the interior of the cylinder? Did you have to mount it to a plate or build a custom cover to prtect the inner sleeve? Ive had a couple of frames done and i know that if its not protected its getting coated or blasted!

[dogger315]

how did you prep your cylider for powdercoating

I'm not powder coating the cylinder. The only items that are getting powder
coated are the items that were originally painted by Honda. On a 1993
motor, that includes the clutch cover, water pump cover, right side case
cover and the cylinder head. The stock ignition cover is plastic but I'm
using an aftermarket item so it got powder coated to match as well.

On your motor, the ignition cover is unfinished aluminum as is the cylinder
head. I don't remember what the stock clutch cover was because I
replaced mine with a Hinson cover (see picture).

If your cylinder is looking ratty, it is possible to media blast it without harm
to the internal surfaces. I use "aircraft" tape which is a metal tape that
can withstand the media. Bolt the cylinder head to the cylinder with old
nuts (the plating on the nuts will be removed). Install an old sparkplug,
use the aircraft tape to seal the water inlet on the head, the exhaust port,
the inlet. the entire gasket surface on the base of the cylinder, and the
RC valve area.

Media blast the cylinder with glass beads at 90 psi. This will clean up the
surface without any damage. When done, remove the head and tape and
clean the crap out of everything in a solvent tank then blow out all the
passages with compressed air. Your cylinder will look brand new.

dogger

[nutty]

Great idea- aircraft tape and media blast! But say i protected all critcal surfaces of the cylinder and right side case, do you see any problem with powder coating them? Im thinking of bolting the entire cylinder ( with head attached, old spark plug installed) to an 1/4'' aluminum plate,and the same with the case and clutch/water pump cover and having them powder coated.

[gsxrdude15]

WOW MAN IT LOOKS GREAT!!! Have been off line for a week or so! keep this comming!

John