Head Gasket Replacement - You use sealer?

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Sep 20, 2004
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#1
First, hi, I'm new to the site and look forward to reading through it. My first searches didn't turn up an answer to my question.

Right to the Questions:
Just replaced a leaking head gasket and it's still leaking.
My questions are, should I be using a spray sealer or should this be sealing with the metal gasket alone? And, since I just installed this gasket, can I remove it, use sealer and just re-install the same gasket, or does it need replaced after being torqued down?

More Detail:
I have a 1990 KDX200 (with an LA sleeve). I got it out of storage to get back to riding after almost ten years. It was blowing sweet smelling white smoke, would only stay running with the choke pulled, and had black specs in the coolant. So I pulled the head off and changed the head gasket. The head and cylinder were flat, clean, and smooth. I torqued the head bolts at 20ft lbs each (service manual said 18ft lbs). Well I started it back up (always starts on 1st or 2nd kick), ran good, but after a few minutes, it still blows white, sweet smelling, smoke when I rev it. I used an OEM Kawasaki head gasket with no sealer.

A little history for those still reading:
Around 1995 the piston broke and I had it steel sleeved (stock bore, back then re-coating wasn't an economical option) and put in a Wiseco Pro-Lite piston. I only rode it three or four times afterward and it ran great. It's been in storage ever since and is in great shape. I changed oil and started it three or four times a year riding it around the yard just to keep it loose. Noticed the white smoke last year. The top end still looks new inside after the rebuild in 1995.

Any other thoughts?

Thanks in advance,
John
 
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#2
Sweet smelling exhaust sounds like it's burning coolant to me. Any chance it was stored with weak antifreeze (or just water) and then froze? could also be leaking from the water pump into the case.
Hope it's something simple,
Mike.
 
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#3
I've been educated by the good folks here that a head gasket can be reused if in good shape by spraying with silver paint, waiting for it to become tacky then installing. Also, copper coat spray is said to work as well. Be sure your gasket is clean and if there is any rubbery RTV like film on it, then remove that as well.
I don't know enough about the rest of your problem, so maybe someone else can chime in on that. But here's a question, are you loosing coolant? I realize you said it is blowing sweet smelling smoke, but if coolant isn't being lost, then you might need to look elsewhere.
Good luck and welcome to our site.
 
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#4
It's definitely burning anti-freeze. It was stored with 50/50 anti-freeze mix, and just changed again (Kawasaki Aluma-Cool 50/50). It would not have ever frozen.

Also, it did have some coolant in the crank case. So I just changed the water pump impeller shaft seal, but not the shaft yet, no noticeable wear.

Would the engine burn anti-freeze coming in from the water pump? I assumed that would just mix with the crank case oil (then separate after shut down). I assumed what was being burned was coming from a head gasket leak.

As far as loosing coolant, I never ran it long enough for any noticeable loss.
 
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#5
You might want to ride it/let it run some. After a blown head gasket, coolant can settle in the cases and exhaust pipe. It may still have residual coolant that is burning off, causing the white smoke. If it dosen't stop after 5 or 10 minutes, then I might suspect the head gasket is still leaking. Good luck, YZ165
 
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#6
a leaking water pump seal just makes the oil milky and tears up bearings after long periods of time. the smoke could be from a leaking head gasket or base gasket possibly.... its been a while since ive been into my 91 so i cant remember if the coolant passages continue to the base of the cylinder and stop at the case or if they are blocked at the bottom of the cylinder
 
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#9
Thanks for the replies, well I picked up some K&W Copper Coat spay gasket sealer.

Before I remove and re-install the head gasket using this I want to verify, if I am burning coolant and getting white puffy smoke when reving the engine, would the coolant only be coming from the head gasket, OR, can a waterpump leak or some other leak into the crank case cause the engine to actually burn coolant also?

Though I do think my waterpump shaft seal was leaking, I had ruled that out as a cause of the burning coolant, could this cause coolant burning?

Thanks
 
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#10
water pump shaft wont cause burning coolant unless your crack case seals are also leaking which i highly doubt
 
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jdbrusch

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#11
Another possibility is it could be leaking between the sleeve and the outer aluminium cylinder casting,this might cause it to come in from one of the ports.
Did you measure or lap the head in case it was warped?
 
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#12
Ooo, that's a scary thought, not sure how I'd fix something like that, well, other than a new cylinder.

I just visually checked for warping with a fine steel straight edge, which it "appears" flawless, even across the sleeve ring.

It was lapped when the sleeve was put in. Even though that was about 9 years ago, it's got less than 10 hours of riding time since then. But if the copper coat doesn"t work I'll certainly have to consider that, which I like better than the sleeve leaking through a port.

I need to pickup a compression tester, I want to check that before (and after) I pull the head off and try the copper coat, which I hope to get done Thursday or Friday evening.

Thanks
 
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#13
Update: Did compression test, was geting 190psi after 5 kicks. But went ahead and removed the head gasket and used a thin layer of Copper Coat just so I won't have to worry about a coolant leak anytime soon.

After starting it back up again, I realized that the coolant I smelled burning was coming from a little steaming off of the outside of the radiator that had dripped down after I refilled the coolant. So, I don't think my head gasket was leaking after I replaced it the first time (though it was definitly leaking before that).

Next is replacing the brake fluid and pads, cleaning and repacking the silencer, and fork oil. Should run like new soon. Took a look a new 2004 KDX200/220 at the dealer. I must say, I certainly did not get that "I gotta upgrade feeling". My 1990 model just seems more down to business, and I'd hate to scratch up a new one.

Thanks for all of the replies.