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  #1  
Old 10-25-2012, 12:06 PM
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Default CR500 New Cylinder.. piston

Hello! dear motocrossers

Are the forged Wiseco pro-lite STD size a good choice for a
brand new oem cylinder?

Thanks from sweden.
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Old 10-25-2012, 12:38 PM
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just get the piston measured and make sure that the clearance is right.
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Old 10-25-2012, 06:28 PM
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Make sure you file fit the rings as well.
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Old 10-25-2012, 08:25 PM
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If you have a good machinist that sets your 500 cylinder around .003'ish (piston to cylinder clearence) you wouldn't need to file your rings. I dont recall ever filing them. They have always been within spec (gap check). With that said, still ensure you do your ring gap check, ensure your ports are chamfered and exhaust bridge is relieved...lastly--drill your piston if you're running forged. Cast pistons do not need to be drilled.

Cylinders from 89-01 are the same..your machinist needs to follow this:


My last top end on my 500:

Fresh 89mm bore, you can see the bridge is relieved...dont worry about the decomp scallops above the port's.


Chamfered Transfers:


Ring gap..stick your ring in, use piston to push it squarely about an inch down..measure:




Wiseco/Forged Piston Instructions....read carefully...


Lube everything up, circlips installed with open ends facing down or up..compress rings with hand..slowly lower cylinder down. Do not twist! Take a peek through your intake and sure your rings are butted up against anti-rotation stops in piston. torque everything down.


Manual download:
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[Only registered and activated users can see links. ]

Last edited by shivermetimbers; 10-26-2012 at 07:00 AM. Reason: Erm..fergot stuff.
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Old 10-26-2012, 06:05 AM
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Thanx alot guys!
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Old 10-26-2012, 06:44 AM
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It's important to remember, a 500 cylinder is set to the piston. It's honed to spec ensuring you have proper clearance. If your machinist doesn't use a torque plate during hone/bore...find some one else......IMHO.
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Old 10-26-2012, 08:13 AM
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checking the clearance when new from the factory is just a little different than going oversize. in the past lots of us have bought a new cylinder and bored or ended up boring it to get the clearance we wanted to begin with (if the cylinder came from the factory a little over what we wanted with the piston available or on hand). I have a fresh cylinder from Honda for my 87, and like the one that came it in in 87 it will work fine with a proX i have on hand and another Wiseco as well.

I have found that the stock cylinder from the factory has all the bridge relief necessary, so if you have one of those I wouldnt cut anymore away, a reline can be different.

Depending on how your shop hones or what hone they use, the torque plate can be useful, though the figures we use are not so high as to distort the cylinders to begin with when cold. I always wonder how much that changes under heat. Anyway, if the shop is using a spring loaded hone, you wont see much of an advantage to the plate. Lots of things have changed at motorcycle shops where boring is concerned and few specialize in it anymore it seems, so an actual machine shop that knows motorcycles is a good place to take one as opposed to most shops.
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Old 10-26-2012, 08:54 AM
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Agreed, I might be more ocd with the use of a plate. It simulates the head being installed during the hone/bore process. Your bore will be round...rings are are round = seal power and longevity. Or take your chance with an out of round bore such in worse case scenario you'll squeak it.

You might be lucky where your at. There have reports of bike machinists not chamfering ports or relieving the bridge.....even after the customer asked for it. Said shop attached a sticky to jug saying it's not necessary and would cause power loss....Lmao!! Point is know your machinist, ask the questions. Not all machinists are familiar with our trusty CR500's.

I am going to break into mine soon after I finish up my CR250 woods bike. I have a buddy that has fresh 89mm jugs plated by millennium w/ worked over heads equipped within decompressor.

Not trying to scare anyone, just be smart ask around and find out who does good work.
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Old 10-26-2012, 09:46 AM
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Great post, SMT. Nice, detailed pictures too.

To add a little more to what's already been said, I also used a new cylinder
on my 500. I sent the cylinder, cylinder head, VForce 3 and exhaust flange
to Eric Gorr. He supplied the Wiseco piston and bored the brand new
cylinder to fit and to insure a perfectly round bore. He also port matched
the intake to the VForce and the exhaust port to the exhaust flange.







I noticed from your pictures, EG also does the bridge relief a little differently than most. So far, so good.



Since these pictures were taken, I've replaced this steel cylinder liner with an Aluminum one and had all
the same work done, then got the cylinder Nikasil plated. I can say, it was money well spent, Saved a
little weight and the piston and cylinder expand at the same rate now.

dogger
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Old 10-26-2012, 11:26 AM
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eric gorr is the man I really like the work he has done for me in the past.
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Old 10-26-2012, 12:27 PM
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dogger, did they take out all the iron in your cylinder?
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Old 10-26-2012, 04:15 PM
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Quote:
did they take out all the iron in your cylinder?
Yes, removed the entire iron liner and replaced it with a blank
Aluminum liner. EG had to cut the ports in, then do all the other
work he normally does. Then the cylinder went to Millinneum
for NSC - Nickel Silicon Carbide plating, supposed to be even
better than Nikasil. Saved just under 2 pounds.

Quote:
eric gorr is the man
Agreed, I'm real happy with the work he's done. The motor
is everything I hoped for.

dogger
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