CR500 Engine Build Part 6
This is the final section of the build. I will cover cylinder and head
installation and finish with the intake and carburetor.
Squirt some clean two stroke oil into the ring landings of the piston.
Carefully spread the rings and install with the mark facing up and the
gap centered on the pin.
Install the two allignment dowels on the left side cylinder studs.
Place a new base gasket on the crankcase and carefully lower the cylinder
over the compressed rings until seated on the crankcase. Be careful not
to rotate the cylinder during this process because it is possible to snag and
break a ring.
Place several drops of oil on the landing and apply anti seize to the cylinder
Install the four flange nuts and using a torque extension tool, torque the
nuts to 29 lbft in three steps and in a criss cross pattern.
Install the coolant drain bolt into the left side of the cylinder using a new
copper washer and torque to 7 lbft. Install the exhaust flange using a new
gasket and torque the bolts to 7 lbft.
Place a new O-ring in the water hose joint.
Install the joint to the right side of the cylinder. Torque the bolts to 7 lbft.
Install the seven cylinder head studs into the top of the cylinder. Prep the
studs with Blue loctite on the bottom and antiseize higher up on the threads.
Torque the studs to 9 lbft. using oposing flange nuts or a stud installer.
Place a new head gasket with the "UP" mark facing aft onto the cylinder.
Install the cylinder head. Apply several drops of oil to the flange landings
and anti-seize to the threads.
Install the cylinder head flange nuts and torque to 20 lbft in three steps and
in a criss cross pattern. Next, install the coolant hose. If you use silicon
hose, make sure to use silicon hose specific hose clamps. These clamps
have a smooth surface around the worm gear and beveled edges so they
won't cut the hose like a normal clamp.
Next up is the intake. I am using a VForce 3 reed valve. This valve requires
the removal of the rubber reed stuffers present on the stock Honda intake.
Spray some Blue Permatex gasket adhesive on one of the gaskets included in
the VForce kit and allow it to tack up.
Place the gasket on the intake.
Use the second included gasket between the VForce reed and the intake
and install using the six hex flange bolts. Torque the bolts to 6.5 lbft.
Install the spark plug and perform a leak down test. Next install the carburetor
in this case a 39.5mm Keihin PWK, and you are done.
This engine should produce close to 70 hp with a smooth useable powerband.
Last edited by dogger315; 01-02-2011 at 07:11 PM.
Awsome job I would pay you to do that to both of my CR500's.
Great Build Dogger!
Thanks for the great "How To" pictorial. I will be rebuilding one of my 500's soon and plan to mimic your build (hope you don't mind).
Couple questions: Why 39.5 vs 41.5 carb? Why V-Force 3 vs RadValve? How would you prep a used cylinder (exterior) for best results? Would you do anything different if you were building it specifically for Glamis?
of post on this build, I detail how I cleaned up and restored the
various parts. The cylinder, clutch and ignition covers are new.
than pure top end. The stock carb is a 38mm PJ so this is a really nice up
grade. Reed valve choice is also with MX in mind, I like the VForce over the
Rad Valve because of the better throttle response. The best way I have
found to clean up a used cylinder is to clean it with solvent followed by
blasting it with glass beads. This will take the cylinder down to a fresh,
brand new Aluminum finish. Follow the media blast with another trip
through the solvent tank and a stint in the ultrasonic parts washer if you
have one. Finally, wipe the bore down with clean two stroke oil. I'm
including some before and after pictures of a cylinder prepped this way.
I'm also including before and after pictures of the cylinder head. You
can also see the after picture of the cylinder head in the build post
because I utilized the used head.
For Glamis, I would recommend the 41mm carb and the Rad Valve along
with some robust jetting to keep you out of trouble at WOT in deep sand.
Before picture of the cylinder during disassembly
After picture of cylinder used for EBay add
Before picture of cylinder head
Thanks for the tips Dogger. I appreciate your willingness to share your knowledge & experience, especially the photos.
that is one great job, like everyone said, thanks for the photos to go along with the build up.
you are hired
will you do my engine? How much will you charge? I have a 2010 Service Honda CR500AF and a 2000 Honda CR500 steelly. Your engine would look sick in my AF500! I want my engine to look that good. But; I use a V-Force Delta 2 reed cage. There is a way to modify that cage and you can do it yourself. It works and its easy to do all you need is a half inch file and sand paper. Seriously will you do my engine. I'm looking to rebiuld the AF500 engine next winter.
your hoon needs a rebuild already. If you want a cosmetic replica
of my engine, I will need to powder coat the right side case cover,
replace the clutch cover with a billet HGA replica, replace the ignition
cover with an HGA unit (if possible) and replace all the stock steel
bolts with titanium ($$$). Depending on current condition, I may
also have to media blast the cylinder and cylinder head. This will give
you an engine that looks like mine but runs like a stock CR500.
Your engine already has the 39.5mm Keihin PWK and that VForce2
is an excellent reed valve that is every bit as good as a 3. Your
engine should also have silicon hoses.
If you want a complete replica of my engine, I will need to completely
disassemble it and send the crank out for balance, replace the tranny
with a close ratio unit, Cryo-REM all the gears, send the cylinder and
head out for port and machine work, new forged piston, 2000 CR250
ignition with a Vortex programmable ignition controller and a Hinson
I can do as much or as little as you want. Pick your "poison" and I can
work up a quote and turn around time.
I like Pro Circuit works or platinum with a 304 silencer the best for the 500.
Rebuild ? For dogger
Excellent work dogger. I have a question about an oil leak I have on a 97 cr5, bought it in pieces, bored the top end out and new piston. Started putting it back together and when I put oil in the crankcase it is slowly leaking from the weep hole by the stator. From what I have read it's either the left crank case seal or the center seal. I really really don't want to split the cases and spend money but I don't want to get this bike going just to blow it up either. Is there a way to tell which seal is out? What's your input? Sorry for posting this on the engine rebuild sticky but I created an account a few minutes ago so I can't email or pm you.
That hole is supposed to drain fluid out of the ignition cavity to a sump cast
into the bottom of the crankcase and out a small opening. Oil draining from
that hole into the ignition cavity sounds like a bad seal between the crankcase
halves. I recommend you re-check the source and make sure the oil is
actually coming out of that drain and not just pooling there as it leaks from
the clutch actuator seal. If it IS coming from that drain, you will have to
split the case again. The problem could be as simple as an out of place
gasket or as serious as a damaged or warped case half. If the problem
is not obvious after you split the cases, put the halves together and run
a feeler gauge the width of a compressed gasket and make sure the gap
is constant especially in the area around the problem.
If the oil is coming from the clutch actuator rod, replace the seal.
Keep us posted on what you find out.
I checked where the oil was coming from three times to finally convince myself that it was coming from the clutch arm, got the seal on the way. Thank you for the help, now time to finish getting this thing together. I fired it up earlier just to check things out, I forgot how much these bikes vibrate.
Good deal! It's always nice when it turns out to be the easy to fix problem.
The 500 does vibrate, but if it feels excessive, check to make sure the
engine mounting bolts are all torqued to spec.
Post some pictures when you get it put back together.
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