Head gasket leaking


Post Reply
DaveMadsen
Forum Regular
Forum Regular
Posts: 45
Joined: Sat Oct 13, 2018 3:58 pm
Location: Pleasant Hill, CA
Location: Pleasant Hill, CA

Head gasket leaking

Post by DaveMadsen »

Actually, the engine is not leaking, rather oozing rapidly. I let the bike idle a minute and had a cup of oil on the garage floor.

I had a similar leak after doing rings and valves and though I had damaged the head gasket during reassembly. I replaced the head gasket and the engine is kicking out even more oil than before I changed the gasket. The head bolts are torqued to 15 and 25 pound (10 pounds for the two 6mm bolts below the timing chain protrusion).

The oil is visually seeping at the head gasket location - virtually the entire perimeter of the head.

Ideas?

Dave

User avatar
NobleHops
ICOA Member
ICOA Member
Posts: 3170
Joined: Mon Jan 25, 2010 8:17 am
Location: Tucson, Arizona, USA
Location: Tucson, Arizona, USA

Re: Head gasket leaking

Post by NobleHops »

The last two we did had to be decked about 9 thou to be made flat again, if the head is coming back off then get a steel straightedge and your feeler gauges and see what’s going on. What a PITA.
I Do Vapor Blasting! viewtopic.php?f=5&t=9881

Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

http://www.restocycle.com Ikon shocks for your CBX! https://www.ikonshocksusa.com/collectio ... 1000-79-80

DaveMadsen
Forum Regular
Forum Regular
Posts: 45
Joined: Sat Oct 13, 2018 3:58 pm
Location: Pleasant Hill, CA
Location: Pleasant Hill, CA

Re: Head gasket leaking

Post by DaveMadsen »

I may have figured it out. When I was doing the rings and had the cyclinder head removed, I cleaned the stud bolts and when I replaced them, I apparently didn't screw them in far enough. Fast forward to finally getting around to reinstalling the head, several of the stud bolts were a turn or two too long and the cap nut tightened against the top of the cap nut, registering the appropriate torque, but not compressing the head against the cylinder block.

A purist would have yanked of the cylinder block and repositioned the stud bolts. Being a bit more pragmatic, I just replaced three cap nuts with nuts having a nylon collar thus alleviating the limitation of the cap nut. Hopefully the nylon collar will prevent oil from slipping past the threads.

User avatar
Jeff Bennetts
Posting God
Posting God
Posts: 1761
Joined: Wed Mar 05, 2003 9:38 am
Location: Ohio, USA
Location: Ohio, USA

Re: Head gasket leaking

Post by Jeff Bennetts »

You probably should pull it apart again, who knows how many of the other studs didn't get seated?
Loctite makes a product for fasteners that are pre-assembled. You might be able to get a few drops down the studs and into the block to keep the studs from backing out, a few drops is al you need!

Loctite Green, #290

daves79x
ICOA Technical Director
ICOA Technical Director
Posts: 3894
Joined: Sun Oct 01, 2006 8:05 am
Location: Knox, PA
Location: Knox, PA

Re: Head gasket leaking

Post by daves79x »

So you removed the studs to clean them? If you managed to get them out with the cylinder on (easy enough to do), you should have been able to reinstall them just fine too. Yes, the height of the studs is critical and if they are not screwed in far enough, sometimes one will start to pull out of the block when trying to torque the nut. You should be able to screw them in completely by just removing the valve cover. If they won't, then the threads are dirty or messed up. I'd be looking to fix it properly - you or the next guy are just asking for trouble.

Dave

DaveMadsen
Forum Regular
Forum Regular
Posts: 45
Joined: Sat Oct 13, 2018 3:58 pm
Location: Pleasant Hill, CA
Location: Pleasant Hill, CA

Re: Head gasket leaking

Post by DaveMadsen »

As far as I can tell, the length of the “long” studs about 2 threads longer than the others but this was enough for the cap nut to bottom out before squishing the head in place. I used blue Loctite when I installed them. I’ll let the forum know how they hold up in another 60,000 miles.

DaveMadsen
Forum Regular
Forum Regular
Posts: 45
Joined: Sat Oct 13, 2018 3:58 pm
Location: Pleasant Hill, CA
Location: Pleasant Hill, CA

Re: Head gasket leaking

Post by DaveMadsen »

Actually I’ll check the torque the next time I check the valves. If there are any irregularities, the. I’ll pull the cylinder block.

Post Reply

Return to “ENGINES: Maintenance, Performance, Parts Sources”