'88 KDX Top End - New Head Gasket Leaking

[Dutch-MI]

So I got the cylinder replated at Millennium along with a .006" surface grind on top of the cylinder and installed new studs. The head was flat and still good. Put everything together per torque spec and performed leak down test and there is a good amount of air escaping from the head gasket.

Do you typically need to heat the engine up to get a good seal with the multilayer steel gasket?

[KDXGarage]

May I ask how you determined that the head was "flat an still good"?

Was there an overheating incident?

I don't think engine temp is related to torque. Just think of when any new engine is assembled in the factory, all done cold.

EDIT: https://www.ebay.com/itm/Kawasaki-NOS-O ... SwlpZaZlmd

[Dutch-MI]

I used feeler gauged based on specs from the Clymer manual. I also sent it into Millennium Technologies when they did the surface grind on the top of cylinder.

I don't think there was an overheating incident that I encountered.

I see the link you provided with OEM gasket which is copper. The one I got from Wiseco was a MLS one.

[KDXGarage]

Hmm. JUST ASKING!! What was your technique on getting it torqued?

[Dutch-MI]

KDXGarage - I appreciate your input. No issues here. Torqued at half spec criss-crossed and then to full spec. I didn't apply any copper spray to the MLS gasket.

Thoughts on applying copper spray to the MLs or replacing the MLS all together for a copper OEM or start up the engine for break in and see if it helps seal?

[KDXGarage]

Your technique sounds right. Did you use a torque wrench?

I don't use spray. The aftermarket gasket should have been good. Maybe a touch higher torque value??

[Dutch-MI]

Yep - used a torque wrench. Went to 18 ft lbs and when I found out it was still leaking, went to 20lbs but that was my limit.

[Dutch-MI]

I don't know if it's standard to do a leak down before you do the break in process. Maybe starting it up and apply heat will help or am I risking a lot?

The Wiseco break procedure doesn't mention anything about a leak down - just to retorque after the break in.

I'm pretty much stuck on what to do next.

[Molly's 70]

Did you check the flatness of the head? How many pounds of compression?

[Dutch-MI]

Well I started the break-in process and fired it up this afternoon with no issues so far. There is no indication of it running lean (power surging / no smoke) or oil leaking by the head gasket so I may be in the clear! Compression felt good but won't know the new psi until rings are seated. Maybe it just needed some heat for the metals to anneal together. Gonna re-torque to spec tonight after it's completely cold. Can't wait to get on this awesome vintage ride for the fall!

[KDXGarage]

Are you sure the air leak was at the head gasket?

What PSI?

NO MATTER WHAT... no coolant leak.

[Dutch-MI]

Yes - air is escaping out by the head gasket when pressurized to 6-7 psi. Did another leak down tonight and it is dramatically better. Got two more break in rides and then will re-torque again and do a final leak down.

What I meant imy previous post on PSI was doing a compression test.