Honda CR250 Engine Build Part 5

[dogger315]

But say i protected all critcal surfaces of the cylinder and right side case, do you see any problem with powder coating them?

No problem at all as long as all seals and any other rubber or plastic parts
are removed. Those items would melt at the 400-450 degree curing temps.

Before you go the mounting plate route, consider this. I recently built a
1979 CR250 motor for another restoration project. It was originally painted
red. I tore the motor down and removed all the internals. I bolted the
case halves together, mounted the cylinder and head and installed the
clutch and ignition cover using old fastners. I covered all the remaining
holes with silicon plugs and hi-temp tape and powder coated the whole
shabang as a unit. After it cooled from curing, I took a razor and cut along
the mounting surfaces (the powder had fused everything together) and
removed each part leaving clean unmolested gasket surfaces and no
powder coat where it shouldn't be. This technique might work for your
application.

Here is a picture of the finished motor. Everything that's red is powder coated,
and it was all done at the same time.

dogger

[IMG][/IMG]

[ccnut]

Andy,Please do!!!!! There is nothing trivial or else about Hodaka!! ....Jerry

[FFRacing11x]

Fantastic writeup...going to have to go back and catch the first installments. The only thing I find questionable is the procedure for the clutch plates. It is a misconception that the plates "soak" or "saturate" with oil. They don't even come that way from the factory when you buy a new bike. Some of the clutch makers are even including in their instructions that oiling the plates is not required. Install dry and when you fire the motor up, just work the lever a few times and the clutch will have all the oil it needs. JMO Tdub

Great write up

[dogger315]

It is a misconception that the plates "soak" or "saturate" with oil

Good point. You are absolutely right, the fiber plates do NOT soak up
oil. I like to "soak" (maybe immerse is a better word) them in oil for a
period of time to ensure each plate is totally covered before the first
engagement under power. The fiber plate work best when a film of
oil is present between it and the adjacent metal plate. I immerse these
plates in oil to help prevent any "dry" section of a fiber plate from spinning
up against a metal plate and glazing. I guess a good comparison is when
an auto engine builder uses a drill to spin the distributor gear to pump oil
throughout a newly rebuilt engine prior to that first start-up. It isn't
required, but it helps extend bearing life.

Some of the clutch makers are even including in their instructions that oiling the plates is not required.

As you pointed out, not everyone agrees with pre-soaking clutch plates, but
some of the brand names like Barnett, EBC and Hinson do. Another one that
recommends it is Honda. Their Shop manual for the motor I am building
states: "Thoroughly coat each fiber clutch plate with transmission oil prior
to installation".

You can debate engine building techniques all day because everybody has
there own way of doing things. I appreciate your input and enjoy discussing
the merits of alternative views. That's how I learn new things, so keep it
coming.

dogger

[FFRacing11x]

Dogger, good job! I read all your steps and it is very well done. I have a few alternative procedures, but it is your thread. Tdub

[dogger315]

Thanks Tdub.

I have a few alternative procedures, but it is your thread

I welcome any and all alternatives you have, I'm not territorial
The whole purpose of this series is to help folks that would like to learn
and do there own work. The more information, the better. I'm sure I will
learn some valuable pointers as well which I am always up for, so please,
post away.

dogger

[dbroms]

great read fella , good work. You say the 93 had some original painted items, i have a 92 cr250, whats the standard for it ? are any parts painted from new or do you know any sites that may have this info ,
thanks
daz

[dogger315]

i have a 92 cr250, are any parts painted from new

The appearance of the 92 engine is identical to the 93. Honda painted
the cylinder head, right case cover, clutch cover and water pump cover.

If you look back on this thread, there is a picture comparing two clutch
covers. The one on the right is brand new right out of the box. That
was the part I used to for my color match. That is also what the clutch
cover looked like on your 92 when it was new.

I can't help you with paint matching because I opted to powder coat
all the parts that were originally painted. I will be glad to steer you
toward the right powder to duplicate the original paint, if you're
interested.

I will be finishing this engine build series in the next week and I will be
posting pictures of the completed project. It will be mostly stock appearing
and you can see what your 92 motor would look like freshened up.

dogger

[bundyho1]

Originally Posted by 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.

So dogger what color did you use for the cover and where did you buy the powder ?I have a friend who can do this on small pieces ..Thanks

[dogger315]

I get the powder from Powder By The Pound: [Only registered and activated users can see links. ]

The color is Silvadillo Silver. Once you get to the website, click on "Metallics"
and scroll down to page two for Silvadillo. One pound is enough for a dozen
motors.

I was amazed at how many variation of the color Silver exsist, and this was
the third company I tried.

If you plan to have a friend do the work, try to do all the prep work yourself
to minimize his work load and also ensure your parts turn out good. It is just
as easy to get a poor powder coating job as a good one.

Here are some tips on what I do that will help you get good results:
1) Dismantle the part down to bare casting (no seals, bearings, etc.)
2) Thoroughly clean the parts with a solvent based cleaner to get all
the dirt and grease off
3) Media blast (I use glass bead on aluminum) to strip old paint or, if
you don't have a blast cabinet, use TAL II Aircraft Coating Remover.
4) Cook in oven at 400 degrees for half an hour to out gas.
5) Clean again with solvent based cleaner and dry with compressed air.
From this point, do not handle part with bare hands to prevent
contamination.

Now you can deliver the parts to your friend. He should spray each item
with an etching solution, wash and dry with compressed air then they are
ready for powder.

If you have any questions, let me know.

dogger

[bundyho1]

You are the man...