1990 Honda CR-500 head gasket problem

YZ-250K
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YZ-250K
Edited Date/Time 11/4/2012 5:59pm
Long story short the bottom end went in this bike about 10 years ago. I then rebuilt the entire motor with new Honda crankshaft assembly, cylinder, weisco piston kit, boyeson rad valve. I was using an aftermarket gasket kit I believe made by moose. Everything went together good until I put the head on. I used permatex copper coat on the head gasket. I then discovered that it leaked by taking the radiator cap off and seeing alot of air bubbles and the copper coat bubbling up. I then tried 2 head gaskets with copper coat and still the same results. Its been sitting in my garage for the last ten years this way. Around a week ago I ordered a brand new cylinder head from Honda and factory head gasket. Today I put it together again with the copper coat. It started right up on the 3rd kick. Pretty good for sitting 10 years. , but yet again its bubbling like crazy and the permatex copper coat is all in the radiator. I torqed the head to 21 foot pounds as it says in the manual, but yet its bubbling like crazy. Im at my witts end to why this is still blowing head gaskets? Should I not use the copper coat? Is there a curing time for copper coat before you start up the engine? All it says on the can is wait 30 seconds between coats it says nothing about curing time. Any motocross wisdom out there that can help me out on this one? Mr know it all? brand new head and cylinder yet leaking? to much compression?
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scooter5002
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scooter5002 10/28/2012 2:15pm
10/28/2012 2:15pm
A little bit of advice for you , since I have a fair bit of Honda 500 experience. Walk out to your shop and find that Copper Kote. Pick it up with your dominant hand, and walk it out to the shop door, and go outside. Once you have made it to the great outdoors, take that fuckin shit and fire it as far as you possibly can. Don't go and look for it. Return inside to your shop.
If you ordered a new cylinder head and factory gasket and it's still leaking, I would assume possibly that the cylinder deck is slightly warped, but it wouldn't hurt to check that new head as well. I could see if your cooling system was polluted with Copper Kote because it wasn't flushed well, but the bubbling indicates there is still a problem. Have a machine shop check war page on your cyl and head.
YZ-250K
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YZ-250K 10/28/2012 4:38pm
10/28/2012 4:38pm
Do you think the copper coat being still wet and tacky would cause it to leak? After I sprayed 1 coat on each side of the gasket I took a hair dryer and tried curing it fast for around 10 minutes. Then assembled. It has a brand new cylinder and head. I never would have thought that they would be warped. Do you think just putting a gasket with out copper spray would cure the problem?
pete24
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pete24 10/28/2012 4:56pm
10/28/2012 4:56pm
you obviosly cant read yes he thinks putting the head gasket in the way honda designed it is the rite way to do it, BUT you still have that can of rubbish go throw it in the woods, have a machine shop deck your cylinder AND your head (caps cuz u aint a good listener) then put it together with an oem head gasket with nothing on it, then try to flush that crap outta your radiators and youll be good to go
4stroke4DWIN
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4stroke4DWIN 10/30/2012 9:31am
10/30/2012 9:31am
Copper coat sucks ballz, that shit is last resort stuck out on the trail with a blizzard coming in. Like scoot said use it for target practice.

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YZ-250K
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YZ-250K 11/1/2012 8:53pm
11/1/2012 8:53pm
Sorry but after reading the offroad motocross manual by eric gorr it says to coat the head gasket with copper coat. that is where I got the idea
supergreg
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supergreg 11/2/2012 4:01pm
11/2/2012 4:01pm
Agree with launching the copper kote. I torque my head down with progressively increasing torque. Zero intitial failures.
seanmx57
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seanmx57 11/3/2012 4:14pm
11/3/2012 4:14pm
I've never had issues with using CC. I build plenty of CR500 motors. In fact you can reuse head gaskets with it or laquer based spray paint. You have other issues.

When using CC I do 2 or 3 light coats and use the 30 sec rule, flip it over do it again. I end up with 2 coats on both sides, sometimes 3 depending if there is a spot that is light.

Are you lubing your threads on the studs? Are you torqueing them progressively in a cris cross pattern? Is the gasket tits facing up?
YZ-250K
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YZ-250K 11/4/2012 9:50am
11/4/2012 9:50am Edited Date/Time 11/4/2012 10:53am
seanmx57 no im not lubing the threads on the head ... should I ? Yes I tighten them in a criss - cross pattern at 10, 15, then 21 ft. lbs. yes the tits are up. How long should the copper coat cure for before assembling the head? Every time that I use it , it will blow the copper coat right into the cooling jacket, radiator, and water pump right after the engine starts up. I now have 3 cycles of coppercoat gasket treatment swirling around from the 3 first attempts
TerryK
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TerryK 11/4/2012 5:59pm
11/4/2012 5:59pm
Never, ever used or needed copper coat on a CR500 (or any other bike) head gasket. As has been said, it most likely is a bad sealing surface on the cylinder or even the head, new or not.

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